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1 .H0 "Discussion
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2 .P
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3 This main chapter discusses the practical work done in the mmh project.
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4 It is structured along the goals to achieve. The concrete work done
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5 is described in the examples of how the general goals were achieved.
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6 The discussion compares the current version of mmh with the state of
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7 nmh just before the mmh project started, i.e. Fall 2011.
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8 Current changes of nmh will be mentioned only as side notes.
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9 .\" XXX where do I discuss the parallel development of nmh?
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10
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11
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12
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13 .H1 "Stream-Lining
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14
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15 .P
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16 MH had been considered an all-in-one system for mail handling.
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17 The community around nmh has a similar understanding.
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18 In fundamental difference, mmh shall be a MUA only.
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19 I believe that the development of all-in-one mail systems is obsolete.
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20 Today, email is too complex to be fully covered by single projects.
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21 Such a project won't be able to excel in all aspects.
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22 Instead, the aspects of email should be covered my multiple projects,
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23 which then can be combined to form a complete system.
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24 Excellent implementations for the various aspects of email exist already.
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25 Just to name three examples: Postfix is a specialized MTA,
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26 Procmail is a specialized MDA, and Fetchmail is a specialized MRA.
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27 I believe that it is best to use such specialized tools instead of
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28 providing the same function again as a side-component in the project.
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29 .P
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30 Doing something well, requires to focus on a small set of specific aspects.
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31 Under the assumption that focused development produces better results
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32 in the particular area, specialized projects will be superior
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33 in their field of focus.
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34 Hence, all-in-one mail system projects \(en no matter if monolithic
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35 or modular \(en will never be the best choice in any of the fields.
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36 Even in providing the best consistent all-in-one system they are likely
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37 to be beaten by projects that focus only on integrating existing mail
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38 components to a homogeneous system.
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39 .P
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40 The limiting resource in Free Software community development
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41 is usually man power.
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42 If the development power is spread over a large development area,
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43 it becomes even more difficult to compete with the specialists in the
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44 various fields.
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45 The concrete situation for MH-based mail systems is even tougher,
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46 given the small and aged community, including both developers and users,
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47 it has.
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48 .P
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49 In consequence, I believe that the available development resources
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50 should focus on the point where MH is most unique.
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51 This is clearly the user interface \(en the MUA.
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52 Peripheral parts should be removed to stream-line mmh for the MUA task.
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53
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54
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55 .H2 "Mail Transfer Facilities
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56 .P
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57 In contrast to nmh, which also provides mail submission and mail retrieval
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58 agents, mmh is a MUA only.
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59 This general difference initiated the development of mmh.
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60 Removing the mail transfer facilities had been the first work task
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61 in the mmh project.
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62 .P
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63 The Mail Submission Agent (MSA) is called
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64 \fIMessage Transfer Service\fP (MTS) in nmh.
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65 The facility established network connections and spoke SMTP to submit
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66 messages for relay to the outside world.
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67 This part was implemented by the
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68 .Pn post
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69 command.
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70 The changes in email in the last years
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71 demanded changes in this part of nmh too.
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72 Encryption and authentication for network connections
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73 needed to be supported, hence TLS and SASL were introduced into nmh.
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74 This added complexity to nmh without improving it in its core functions.
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75 Also, keeping up with recent developments in the field of
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76 mail transfer requires development power and specialists.
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77 In mmh this whole facility was simply cut off.
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78 .Ci f6aa95b724fd8c791164abe7ee5468bf5c34f226
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79 .Ci fecd5d34f65597a4dfa16aeabea7d74b191532c3
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80 .Ci 156d35f6425bea4c1ed3c4c79783dc613379c65b
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81 Instead, mmh depends on an external MSA.
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82 The only outgoing interface available to mmh is the
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83 .Pn sendmail
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84 command, which almost any MSA provides.
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85 If not, a wrapper program can be written.
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86 It must read the message from the standard input, extract the
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87 recipient addresses from the message header, and hand the message
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88 over to the MSA.
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89 For example, a wrapper script for qmail would be:
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90 .VS
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91 #!/bin/sh
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92 # ignore command line arguments
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93 exec qmail-inject
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94 VE
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95 The requirement to parse the recipient addresses out of the message header
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96 is likely to be removed in the future.
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97 Then mmh would give the recipient addresses as command line arguments.
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98 This appears to be the better interface.
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99 .\" XXX implement it
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100 .P
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101 To retrieve mail, the
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102 .Pn inc
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103 command acted as Mail Retrieval Agent (MRA).
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104 It established network connections
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105 and spoke POP3 to retrieve mail from remote servers.
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106 As with mail submission, the network connections required encryption and
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107 authentication, thus TLS and SASL were added.
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108 Support for message retrieval through IMAP will become necessary
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109 to be added soon, too, and likewise for any other changes in mail transfer.
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110 Not so for mmh because it has dropped the support for retrieving mail
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111 from remote locations.
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112 .Ci ab7b48411962d26439f92f35ed084d3d6275459c
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113 Instead, it depends on an external tool to cover this task.
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114 In mmh exist two paths for messages to enter mmh's mail storage:
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115 (1) Mail can be incorporated with
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116 .Pn inc
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117 from the system maildrop, or (2) with
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118 .Pn rcvstore
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119 by reading them, one at a time, from the standard input.
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120 .P
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121 With the removal of the MSA and MRA, mmh converted from an all-in-one
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122 mail system to being a MUA only.
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123 Now, of course, mmh depends on third-party software.
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124 An external MSA is required to transfer mail to the outside world;
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125 an external MRA is required to retrieve mail from remote machines.
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126 There exist excellent implementations of such software,
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127 which do this specific task likely better than the internal
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128 versions had done it.
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129 Also, the best suiting programs can be freely chosen.
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130 .P
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131 As it had already been possible to use an external MSA or MRA,
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132 why not keep the internal version for convenience?
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133 The question whether there is sense in having a fall-back pager in all
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134 the command line tools, for the cases when
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135 .Pn more
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136 or
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137 .Pn less
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138 aren't available, appears to be ridiculous.
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139 Of course, MSAs and MRAs are more complex than text pagers
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140 and not necessarily available but still the concept of orthogonal
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141 design holds: ``Write programs that do one thing and do it well.''
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142 .[
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143 mcilroy unix phil
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144 p. 53
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145 .]
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146 .[
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147 mcilroy bstj foreword
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148 .]
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149 Here, this part of the Unix philosophy was applied not only
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150 to the programs but to the project itself.
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151 In other words:
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152 ``Develop projects that focus on one thing and do it well.''
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153 Projects grown complex should be split for the same reasons programs grown
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154 complex should be split.
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155 If it is conceptionally more elegant to have the MSA and MRA as
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156 separate projects then they should be separated.
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157 This is the case here, in my opinion.
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158 The RFCs propose this separation by clearly distinguishing the different
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159 mail handling tasks.
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160 .[
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161 rfc 821
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162 .]
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163 The small interfaces between the mail agents support the separation.
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164 .P
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165 In the beginning, email had been small and simple.
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166 At that time,
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167 .Pn /bin/mail
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168 had covered anything there was to email and still had been small
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169 and simple.
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170 Later, the essential complexity of email increased.
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171 (Essential complexity is the complexity defined by the problem itself.\0
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172 .[[
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173 brooks no silver bullet
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174 .]])
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175 Email systems reacted to this change: They grew.
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176 RFCs started to introduce the concept of mail agents to separate the
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177 various tasks because they became more extensive and new tasks appeared.
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178 As the mail systems grew even more, parts were split off.
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179 In nmh, for instance, the POP server, which was included in the original
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180 MH, was removed.
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181 Now is the time to go one step further and split the MSA and MRA off, too.
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182 Not only does this decrease the code size of the project,
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183 but, more important, it unburdens mmh of the whole field of
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184 message transfer with all its implications for the project.
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185 There is no more need to concern with changes in network transfer.
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186 This independence is received by depending on an external program
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187 that covers the field.
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188 Today, this is a reasonable exchange.
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189 .P
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190 Functionality can be added in three different ways:
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191 .BU
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192 Implementing the function originally in the project.
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193 .BU
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194 Depending on a library that provides the function.
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195 .BU
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196 Depending on a program that provides the function.
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197 .P
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198 Whereas adding the function originally to the project increases the
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199 code size most and requires most maintenance and development work,
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200 it makes the project most independent of other software.
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201 Using libraries or external programs require less maintenance work
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202 but introduces dependencies on external software.
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203 Programs have the smallest interfaces and provide the best separation
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204 but possibly limit the information exchange.
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205 External libraries are stronger connected than external programs,
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206 thus information can be exchanged more flexible.
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207 Adding code to a project increases maintenance work.
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208 .\" XXX ref
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209 Implementing complex functions originally in the project adds
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210 a lot of code.
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211 This should be avoided if possible.
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212 Hence, the dependencies only change in kind, not in their existence.
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213 In mmh, library dependencies on
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214 .Pn libsasl2
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215 and
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216 .Pn libcrypto /\c
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217 .Pn libssl
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218 were treated against program dependencies on an MSA and an MRA.
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219 This also meant treating build-time dependencies against run-time
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220 dependencies.
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221 Besides program dependencies providing the stronger separation
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222 and being more flexible, they also allowed
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223 over 6\|000 lines of code to be removed from mmh.
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224 This made mmh's code base about 12\|% smaller.
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225 Reducing the project's code size by such an amount without actually
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226 losing functionality is a convincing argument.
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227 Actually, as external MSAs and MRAs are likely superior to the
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228 project's internal versions, the common user even gains functionality.
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229 .P
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230 Users of MH should not have problems to set up an external MSA and MRA.
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231 Also, the popular MSAs and MRAs have large communities and a lot
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232 of documentation available.
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233 Choices for MSAs range from full-featured MTAs like
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234 .I Postfix
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235 over mid-size MTAs like
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236 .I masqmail
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237 and
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238 .I dma
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239 to small forwarders like
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240 .I ssmtp
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241 and
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242 .I nullmailer .
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243 Choices for MRAs include
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244 .I fetchmail ,
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245 .I getmail ,
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246 .I mpop
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247 and
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248 .I fdm .
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249
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250
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251 .H2 "Non-MUA Tools
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252 .P
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253 One goal of mmh is to remove the tools that are not part of the MUA's task.
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254 Further more, any tools that don't improve the MUA's job significantly
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255 should be removed.
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256 Loosely related and rarely used tools distract from the lean appearance.
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257 They require maintenance work without adding much to the core task.
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258 By removing these tools, the project shall become more stream-lined
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259 and focused.
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260 In mmh the following tools are not available anymore:
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261 .BU
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262 .Pn conflict
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263 was removed
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264 .Ci 8b235097cbd11d728c07b966cf131aa7133ce5a9
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265 because it is a mail system maintenance tool that is not MUA-related.
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266 It even checked
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267 .Fn /etc/passwd
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268 and
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269 .Fn /etc/group
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270 for consistency, which is completely unrelated to email.
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271 A tool like
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272 .Pn conflict
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273 is surely useful, but it should not be shipped with mmh.
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274 .\" XXX historic reasons?
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275 .BU
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276 .Pn rcvtty
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277 was removed
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278 .Ci 14767c94b3827be7c867196467ed7aea5f6f49b0
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279 because its use case of writing to the user's terminal
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280 on receiving of mail is obsolete.
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281 If users like to be informed of new mail, the shell's
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282 .Ev MAILPATH
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283 variable or graphical notifications are technically more appealing.
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284 Writing directly to terminals is hardly ever wanted today.
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285 If though one wants to have it this way, the standard tool
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286 .Pn write
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287 can be used in a way similar to:
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288 .VS
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289 scan -file - | write `id -un`
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290 VE
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291 .BU
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292 .Pn viamail
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293 was removed
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294 .Ci eda72d6a7a7c20ff123043fb7f19c509ea01f932
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295 when the new attachment system was activated, because
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296 .Pn forw
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297 could then cover the task itself.
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298 The program
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299 .Pn sendfiles
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300 was rewritten as a shell script wrapper around
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301 .Pn forw .
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302 .Ci 0e82199cf3c991a173e0ac8aa776efdb3ded61e6
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303 .BU
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304 .Pn msgchk
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305 was removed
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meillo@87
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306 .Ci bb9360ead7eb7a3fedcce2eeedfc660014e41dbe ,
|
|
meillo@87
|
307 because it lost its use case when POP support was removed.
|
|
meillo@76
|
308 A call to
|
|
meillo@58
|
309 .Pn msgchk
|
|
meillo@87
|
310 provided hardly more information than:
|
|
meillo@82
|
311 .VS
|
|
meillo@58
|
312 ls -l /var/mail/meillo
|
|
meillo@82
|
313 VE
|
|
meillo@100
|
314 It did distinguish between old and new mail, but
|
|
meillo@100
|
315 this detail information can be retrieved with
|
|
meillo@76
|
316 .Pn stat (1),
|
|
meillo@62
|
317 too.
|
|
meillo@100
|
318 A small shell script could be written to print the information
|
|
meillo@76
|
319 in a similar way, if truly necessary.
|
|
meillo@76
|
320 As mmh's
|
|
meillo@76
|
321 .Pn inc
|
|
meillo@87
|
322 only incorporates mail from the user's local maildrop,
|
|
meillo@62
|
323 and thus no data transfers over slow networks are involved,
|
|
meillo@76
|
324 there's hardly any need to check for new mail before incorporating it.
|
|
meillo@62
|
325 .BU
|
|
meillo@58
|
326 .Pn msh
|
|
meillo@87
|
327 was removed
|
|
meillo@76
|
328 .Ci 916690191222433a6923a4be54b0d8f6ac01bd02
|
|
meillo@87
|
329 because the tool was in conflict with the philosophy of MH.
|
|
meillo@76
|
330 It provided an interactive shell to access the features of MH,
|
|
meillo@76
|
331 but it wasn't just a shell, tailored to the needs of mail handling.
|
|
meillo@76
|
332 Instead it was one large program that had several MH tools built in.
|
|
meillo@76
|
333 This conflicts with the major feature of MH of being a tool chest.
|
|
meillo@76
|
334 .Pn msh 's
|
|
meillo@76
|
335 main use case had been accessing Bulletin Boards, which have seized to
|
|
meillo@62
|
336 be popular.
|
|
meillo@62
|
337 .P
|
|
meillo@62
|
338 Removing
|
|
meillo@58
|
339 .Pn msh ,
|
|
meillo@76
|
340 together with the truly archaic code relicts
|
|
meillo@58
|
341 .Pn vmh
|
|
meillo@58
|
342 and
|
|
meillo@58
|
343 .Pn wmh ,
|
|
meillo@62
|
344 saved more than 7\|000 lines of C code \(en
|
|
meillo@66
|
345 about 15\|% of the project's original source code amount.
|
|
meillo@100
|
346 Having less code \(en with equal readability, of course \(en
|
|
meillo@76
|
347 for the same functionality is an advantage.
|
|
meillo@63
|
348 Less code means less bugs and less maintenance work.
|
|
meillo@76
|
349 As
|
|
meillo@63
|
350 .Pn rcvtty
|
|
meillo@63
|
351 and
|
|
meillo@63
|
352 .Pn msgchk
|
|
meillo@87
|
353 are assumed to be rarely used and can be implemented in different ways,
|
|
meillo@87
|
354 why should one keep them?
|
|
meillo@76
|
355 Removing them stream-lines mmh.
|
|
meillo@63
|
356 .Pn viamail 's
|
|
meillo@63
|
357 use case is now partly obsolete and partly covered by
|
|
meillo@63
|
358 .Pn forw ,
|
|
meillo@76
|
359 hence there's no reason to still maintain it.
|
|
meillo@63
|
360 .Pn conflict
|
|
meillo@76
|
361 is not related to the mail client, and
|
|
meillo@63
|
362 .Pn msh
|
|
meillo@63
|
363 conflicts with the basic concept of MH.
|
|
meillo@76
|
364 Theses two tools might still be useful, but they should not be part of mmh.
|
|
meillo@63
|
365 .P
|
|
meillo@76
|
366 Finally, there's
|
|
meillo@76
|
367 .Pn slocal .
|
|
meillo@76
|
368 .Pn slocal
|
|
meillo@76
|
369 is an MDA and thus not directly MUA-related.
|
|
meillo@100
|
370 It should be removed from mmh, because including it conflicts with
|
|
meillo@100
|
371 the idea that mmh is a MUA only.
|
|
meillo@100
|
372 .Pn slocal
|
|
meillo@100
|
373 should rather become a separate project.
|
|
meillo@87
|
374 However,
|
|
meillo@76
|
375 .Pn slocal
|
|
meillo@76
|
376 provides rule-based processing of messages, like filing them into
|
|
meillo@76
|
377 different folders, which is otherwise not available in mmh.
|
|
meillo@87
|
378 Although
|
|
meillo@76
|
379 .Pn slocal
|
|
meillo@87
|
380 does neither pull in dependencies nor does it include a separate
|
|
meillo@100
|
381 technical area (cf. Sec. XXX), still,
|
|
meillo@100
|
382 it accounts for about 1\|000 lines of code that need to be maintained.
|
|
meillo@76
|
383 As
|
|
meillo@76
|
384 .Pn slocal
|
|
meillo@76
|
385 is almost self-standing, it should be split off into a separate project.
|
|
meillo@76
|
386 This would cut the strong connection between the MUA mmh and the MDA
|
|
meillo@76
|
387 .Pn slocal .
|
|
meillo@87
|
388 For anyone not using MH,
|
|
meillo@87
|
389 .Pn slocal
|
|
meillo@87
|
390 would become yet another independent MDA, like
|
|
meillo@87
|
391 .I procmail .
|
|
meillo@100
|
392 Then
|
|
meillo@87
|
393 .Pn slocal
|
|
meillo@100
|
394 could be installed without the complete MH system.
|
|
meillo@76
|
395 Likewise, mmh users could decide to use
|
|
meillo@76
|
396 .I procmail
|
|
meillo@87
|
397 without having a second, unused MDA,
|
|
meillo@87
|
398 .Pn slocal ,
|
|
meillo@76
|
399 installed.
|
|
meillo@100
|
400 That appears to be conceptionally the best solution.
|
|
meillo@76
|
401 Yet,
|
|
meillo@76
|
402 .Pn slocal
|
|
meillo@87
|
403 is not split off.
|
|
meillo@100
|
404 I defer the decision over
|
|
meillo@78
|
405 .Pn slocal
|
|
meillo@100
|
406 in need for deeper investigation.
|
|
meillo@100
|
407 In the meanwhile, it remains part of mmh.
|
|
meillo@100
|
408 That does not hurt because
|
|
meillo@100
|
409 .Pn slocal
|
|
meillo@100
|
410 is unrelated to the rest of the project.
|
|
meillo@0
|
411
|
|
meillo@58
|
412
|
|
meillo@76
|
413 .H2 "\fLshow\fP and \fPmhshow\fP
|
|
meillo@58
|
414 .P
|
|
meillo@69
|
415 Since the very beginning \(en already in the first concept paper \(en
|
|
meillo@58
|
416 .Pn show
|
|
meillo@62
|
417 had been MH's message display program.
|
|
meillo@58
|
418 .Pn show
|
|
meillo@76
|
419 mapped message numbers and sequences to files and invoked
|
|
meillo@58
|
420 .Pn mhl
|
|
meillo@89
|
421 to have the files formatted.
|
|
meillo@88
|
422 With MIME, this approach wasn't sufficient anymore.
|
|
meillo@100
|
423 MIME messages can consist of multiple parts. Some parts are not
|
|
meillo@100
|
424 directly displayable and text content might be encoded in
|
|
meillo@58
|
425 foreign charsets.
|
|
meillo@58
|
426 .Pn show 's
|
|
meillo@76
|
427 understanding of messages and
|
|
meillo@58
|
428 .Pn mhl 's
|
|
meillo@88
|
429 display capabilities couldn't cope with the task any longer.
|
|
meillo@62
|
430 .P
|
|
meillo@88
|
431 Instead of extending these tools, additional tools were written from
|
|
meillo@88
|
432 scratch and added to the MH tool chest.
|
|
meillo@88
|
433 Doing so is encouraged by the tool chest approach.
|
|
meillo@88
|
434 Modular design is a great advantage for extending a system,
|
|
meillo@88
|
435 as new tools can be added without interfering with existing ones.
|
|
meillo@62
|
436 First, the new MIME features were added in form of the single program
|
|
meillo@58
|
437 .Pn mhn .
|
|
meillo@58
|
438 The command
|
|
meillo@82
|
439 .Cl "mhn -show 42
|
|
meillo@58
|
440 would show the MIME message numbered 42.
|
|
meillo@58
|
441 With the 1.0 release of nmh in February 1999, Richard Coleman finished
|
|
meillo@58
|
442 the split of
|
|
meillo@58
|
443 .Pn mhn
|
|
meillo@88
|
444 into a set of specialized tools, which together covered the
|
|
meillo@88
|
445 multiple aspects of MIME.
|
|
meillo@88
|
446 One of them was
|
|
meillo@69
|
447 .Pn mhshow ,
|
|
meillo@88
|
448 which replaced
|
|
meillo@88
|
449 .Cl "mhn -show" .
|
|
meillo@88
|
450 It was capable of displaying MIME messages appropriately.
|
|
meillo@62
|
451 .P
|
|
meillo@88
|
452 From then on, two message display tools were part of nmh,
|
|
meillo@76
|
453 .Pn show
|
|
meillo@76
|
454 and
|
|
meillo@76
|
455 .Pn mhshow .
|
|
meillo@88
|
456 To ease the life of users,
|
|
meillo@69
|
457 .Pn show
|
|
meillo@69
|
458 was extended to automatically hand the job over to
|
|
meillo@69
|
459 .Pn mhshow
|
|
meillo@69
|
460 if displaying the message would be beyond
|
|
meillo@69
|
461 .Pn show 's
|
|
meillo@69
|
462 abilities.
|
|
meillo@88
|
463 In consequence, the user would simply invoke
|
|
meillo@69
|
464 .Pn show
|
|
meillo@69
|
465 (possibly through
|
|
meillo@69
|
466 .Pn next
|
|
meillo@69
|
467 or
|
|
meillo@69
|
468 .Pn prev )
|
|
meillo@69
|
469 and get the message printed with either
|
|
meillo@69
|
470 .Pn show
|
|
meillo@69
|
471 or
|
|
meillo@69
|
472 .Pn mhshow ,
|
|
meillo@69
|
473 whatever was more appropriate.
|
|
meillo@69
|
474 .P
|
|
meillo@69
|
475 Having two similar tools for essentially the same task is redundant.
|
|
meillo@88
|
476 Usually,
|
|
meillo@88
|
477 users wouldn't distinguish between
|
|
meillo@88
|
478 .Pn show
|
|
meillo@88
|
479 and
|
|
meillo@88
|
480 .Pn mhshow
|
|
meillo@88
|
481 in their daily mail reading.
|
|
meillo@88
|
482 Having two separate display programs was therefore mainly unnecessary
|
|
meillo@88
|
483 from a user's point of view.
|
|
meillo@88
|
484 Besides, the development of both programs needed to be in sync,
|
|
meillo@76
|
485 to ensure that the programs behaved in a similar way,
|
|
meillo@76
|
486 because they were used like a single tool.
|
|
meillo@76
|
487 Different behavior would have surprised the user.
|
|
meillo@69
|
488 .P
|
|
meillo@69
|
489 Today, non-MIME messages are rather seen to be a special case of
|
|
meillo@100
|
490 MIME messages, although it is the other way round.
|
|
meillo@69
|
491 As
|
|
meillo@69
|
492 .Pn mhshow
|
|
meillo@88
|
493 had already be able to display non-MIME messages, it appeared natural
|
|
meillo@69
|
494 to drop
|
|
meillo@69
|
495 .Pn show
|
|
meillo@69
|
496 in favor of using
|
|
meillo@69
|
497 .Pn mhshow
|
|
meillo@69
|
498 exclusively.
|
|
meillo@88
|
499 .Ci 4c1efddfd499300c7e74263e57d8aa137e84c853
|
|
meillo@88
|
500 Removing
|
|
meillo@88
|
501 .Pn show
|
|
meillo@88
|
502 is no loss in function, because functionally
|
|
meillo@88
|
503 .Pn mhshow
|
|
meillo@88
|
504 covers it completely.
|
|
meillo@88
|
505 The old behavior of
|
|
meillo@88
|
506 .Pn show
|
|
meillo@88
|
507 can still be emulated with the simple command line:
|
|
meillo@88
|
508 .VS
|
|
meillo@88
|
509 mhl `mhpath c`
|
|
meillo@88
|
510 VE
|
|
meillo@88
|
511 .P
|
|
meillo@76
|
512 For convenience,
|
|
meillo@76
|
513 .Pn mhshow
|
|
meillo@88
|
514 was renamed to
|
|
meillo@88
|
515 .Pn show
|
|
meillo@88
|
516 after
|
|
meillo@88
|
517 .Pn show
|
|
meillo@88
|
518 was gone.
|
|
meillo@88
|
519 It is clear that such a rename may confuse future developers when
|
|
meillo@88
|
520 trying to understand the history.
|
|
meillo@88
|
521 Nevertheless, I consider the convenience on the user's side,
|
|
meillo@88
|
522 to call
|
|
meillo@88
|
523 .Pn show
|
|
meillo@88
|
524 when they want a message to be displayed, to outweigh the inconvenience
|
|
meillo@88
|
525 on the developer's side when understanding the project history.
|
|
meillo@69
|
526 .P
|
|
meillo@88
|
527 To prepare for the transition,
|
|
meillo@69
|
528 .Pn mhshow
|
|
meillo@69
|
529 was reworked to behave more like
|
|
meillo@69
|
530 .Pn show
|
|
meillo@69
|
531 first.
|
|
meillo@88
|
532 (cf. Sec. XXX)
|
|
meillo@88
|
533 Once the tools behaved more alike, the replacing appeared to be
|
|
meillo@88
|
534 even more natural.
|
|
meillo@88
|
535 Today, mmh's new
|
|
meillo@69
|
536 .Pn show
|
|
meillo@88
|
537 became the one single message display program again, with the difference
|
|
meillo@88
|
538 that today it handles MIME messages as well as non-MIME messages.
|
|
meillo@88
|
539 The outcome of the transition is one program less to maintain,
|
|
meillo@88
|
540 no second display program for users to deal with,
|
|
meillo@88
|
541 and less system complexity.
|
|
meillo@69
|
542 .P
|
|
meillo@88
|
543 Still, removing the old
|
|
meillo@69
|
544 .Pn show
|
|
meillo@88
|
545 hurts in one regard: It had been such a simple program.
|
|
meillo@88
|
546 Its lean elegance is missing to the new
|
|
meillo@69
|
547 .Pn show .
|
|
meillo@88
|
548 But there is no chance;
|
|
meillo@88
|
549 supporting MIME demands for higher essential complexity.
|
|
meillo@58
|
550
|
|
meillo@58
|
551
|
|
meillo@100
|
552 .H2 "Configure Options
|
|
meillo@58
|
553 .P
|
|
meillo@76
|
554 Customization is a double-edged sword.
|
|
meillo@76
|
555 It allows better suiting setups, but not for free.
|
|
meillo@76
|
556 There is the cost of code complexity to be able to customize.
|
|
meillo@76
|
557 There is the cost of less tested setups, because there are
|
|
meillo@72
|
558 more possible setups and especially corner-cases.
|
|
meillo@76
|
559 And, there is the cost of choice itself.
|
|
meillo@76
|
560 The code complexity directly affects the developers.
|
|
meillo@72
|
561 Less tested code affects both, users and developers.
|
|
meillo@76
|
562 The problem of choice affects the users, for once by having to
|
|
meillo@100
|
563 choose, but also by more complex interfaces that require more documentation.
|
|
meillo@72
|
564 Whenever options add little advantages, they should be considered for
|
|
meillo@72
|
565 removal.
|
|
meillo@72
|
566 I have reduced the number of project-specific configure options from
|
|
meillo@72
|
567 fifteen to three.
|
|
meillo@74
|
568
|
|
meillo@76
|
569 .U3 "Mail Transfer Facilities
|
|
meillo@74
|
570 .P
|
|
meillo@85
|
571 With the removal of the mail transfer facilities five configure
|
|
meillo@85
|
572 options vanished:
|
|
meillo@85
|
573 .P
|
|
meillo@85
|
574 The switches
|
|
meillo@85
|
575 .Sw --with-tls
|
|
meillo@85
|
576 and
|
|
meillo@85
|
577 .Sw --with-cyrus-sasl
|
|
meillo@89
|
578 had activated the support for transfer encryption and authentication.
|
|
meillo@85
|
579 This is not needed anymore.
|
|
meillo@85
|
580 .Ci fecd5d34f65597a4dfa16aeabea7d74b191532c3
|
|
meillo@85
|
581 .Ci 156d35f6425bea4c1ed3c4c79783dc613379c65b
|
|
meillo@85
|
582 .P
|
|
meillo@85
|
583 The configure switch
|
|
meillo@85
|
584 .Sw --enable-pop
|
|
meillo@85
|
585 activated the message retrieval facility.
|
|
meillo@85
|
586 The code area that would be conditionally compiled in for TLS and SASL
|
|
meillo@85
|
587 support had been small.
|
|
meillo@85
|
588 The conditionally compiled code area for POP support had been much larger.
|
|
meillo@85
|
589 Whereas the code base changes would only slightly change on toggling
|
|
meillo@85
|
590 TLS or SASL support, it changed much on toggling POP support.
|
|
meillo@85
|
591 The changes in the code base could hardly be overviewed.
|
|
meillo@85
|
592 By having POP support togglable a second code base had been created,
|
|
meillo@85
|
593 one that needed to be tested.
|
|
meillo@85
|
594 This situation is basically similar for the conditional TLS and SASL
|
|
meillo@85
|
595 code, but there the changes are minor and can yet be overviewed.
|
|
meillo@85
|
596 Still, conditional compilation of a code base creates variations
|
|
meillo@85
|
597 of the original program.
|
|
meillo@85
|
598 More variations require more testing and maintenance work.
|
|
meillo@85
|
599 .P
|
|
meillo@85
|
600 Two other options only specified default configuration values:
|
|
meillo@100
|
601 .Sw --with-mts
|
|
meillo@100
|
602 defined the default transport service, either
|
|
meillo@100
|
603 .Ar smtp
|
|
meillo@100
|
604 or
|
|
meillo@100
|
605 .Ar sendmail .
|
|
meillo@85
|
606 In mmh this fixed to
|
|
meillo@85
|
607 .Ar sendmail .
|
|
meillo@85
|
608 .Ci f6aa95b724fd8c791164abe7ee5468bf5c34f226
|
|
meillo@85
|
609 With
|
|
meillo@100
|
610 .Sw --with-smtpservers
|
|
meillo@85
|
611 default SMTP servers for the
|
|
meillo@85
|
612 .Ar smtp
|
|
meillo@85
|
613 transport service could be specified.
|
|
meillo@72
|
614 .Ci 128545e06224233b7e91fc4c83f8830252fe16c9
|
|
meillo@85
|
615 Both of them became irrelevant.
|
|
meillo@72
|
616
|
|
meillo@74
|
617 .U3 "Backup Prefix
|
|
meillo@74
|
618 .P
|
|
meillo@76
|
619 The backup prefix is the string that was prepended to message
|
|
meillo@76
|
620 filenames to tag them as deleted.
|
|
meillo@76
|
621 By default it had been the comma character `\f(CW,\fP'.
|
|
meillo@78
|
622 In July 2000, Kimmo Suominen introduced
|
|
meillo@78
|
623 the configure option
|
|
meillo@78
|
624 .Sw --with-hash-backup
|
|
meillo@78
|
625 to change the default to the hash symbol `\f(CW#\fP'.
|
|
meillo@78
|
626 The choice was probably personal preference, because first, the
|
|
meillo@78
|
627 option was named
|
|
meillo@78
|
628 .Sw --with-backup-prefix.
|
|
meillo@78
|
629 and had the prefix symbol as argument.
|
|
meillo@100
|
630 But giving the hash symbol as argument caused too many problems
|
|
meillo@100
|
631 for Autoconf,
|
|
meillo@100
|
632 thus the option was limited to use the hash symbol as the default prefix.
|
|
meillo@100
|
633 This supports the assumption, that the choice for the hash was
|
|
meillo@100
|
634 personal preference only.
|
|
meillo@100
|
635 Being related or not, words that start with the hash symbol
|
|
meillo@78
|
636 introduce a comment in the Unix shell.
|
|
meillo@72
|
637 Thus, the command line
|
|
meillo@72
|
638 .Cl "rm #13 #15
|
|
meillo@72
|
639 calls
|
|
meillo@72
|
640 .Pn rm
|
|
meillo@72
|
641 without arguments because the first hash symbol starts the comment
|
|
meillo@72
|
642 that reaches until the end of the line.
|
|
meillo@72
|
643 To delete the backup files,
|
|
meillo@72
|
644 .Cl "rm ./#13 ./#15"
|
|
meillo@72
|
645 needs to be used.
|
|
meillo@100
|
646 Using the hash as backup prefix can be seen as a precaution against
|
|
meillo@78
|
647 data loss.
|
|
meillo@78
|
648 .P
|
|
meillo@72
|
649 I removed the configure option but added the profile entry
|
|
meillo@72
|
650 .Pe backup-prefix ,
|
|
meillo@72
|
651 which allows to specify an arbitrary string as backup prefix.
|
|
meillo@72
|
652 .Ci 6c40d481d661d532dd527eaf34cebb6d3f8ed086
|
|
meillo@76
|
653 Profile entries are the common method to change mmh's behavior.
|
|
meillo@76
|
654 This change did not remove the choice but moved it to a location where
|
|
meillo@72
|
655 it suited better.
|
|
meillo@76
|
656 .P
|
|
meillo@78
|
657 Eventually, however, the new trash folder concept
|
|
meillo@78
|
658 .Cf "Sec. XXX
|
|
meillo@78
|
659 obsoleted the concept of the backup prefix completely.
|
|
meillo@78
|
660 .Ci 8edc5aaf86f9f77124664f6801bc6c6cdf258173
|
|
meillo@100
|
661 .\" (Well, there still are corner-cases to remove until the backup
|
|
meillo@100
|
662 .\" prefix can be laid to rest, eventually.)
|
|
meillo@72
|
663 .\" FIXME: Do this work in the code!
|
|
meillo@76
|
664
|
|
meillo@76
|
665 .U3 "Editor and Pager
|
|
meillo@74
|
666 .P
|
|
meillo@74
|
667 The two configure options
|
|
meillo@74
|
668 .CW --with-editor=EDITOR
|
|
meillo@74
|
669 .CW --with-pager=PAGER
|
|
meillo@74
|
670 were used to specify the default editor and pager at configure time.
|
|
meillo@74
|
671 Doing so at configure time made sense in the Eighties,
|
|
meillo@76
|
672 when the set of available editors and pagers varied much across
|
|
meillo@76
|
673 different systems.
|
|
meillo@89
|
674 Today, the situation is more homogeneous.
|
|
meillo@74
|
675 The programs
|
|
meillo@74
|
676 .Pn vi
|
|
meillo@74
|
677 and
|
|
meillo@74
|
678 .Pn more
|
|
meillo@76
|
679 can be expected to be available on every Unix system,
|
|
meillo@74
|
680 as they are specified by POSIX since two decades.
|
|
meillo@74
|
681 (The specifications for
|
|
meillo@74
|
682 .Pn vi
|
|
meillo@74
|
683 and
|
|
meillo@74
|
684 .Pn more
|
|
meillo@74
|
685 appeared in
|
|
meillo@74
|
686 .[
|
|
meillo@74
|
687 posix 1987
|
|
meillo@74
|
688 .]
|
|
meillo@74
|
689 and,
|
|
meillo@74
|
690 .[
|
|
meillo@74
|
691 posix 1992
|
|
meillo@74
|
692 .]
|
|
meillo@74
|
693 respectively.)
|
|
meillo@74
|
694 As a first step, these two tools were hard-coded as defaults.
|
|
meillo@74
|
695 .Ci 5d43a99db70c12a673028c7758c20cbe3e13ef5f
|
|
meillo@74
|
696 Not changed were the
|
|
meillo@74
|
697 .Pe editor
|
|
meillo@74
|
698 and
|
|
meillo@74
|
699 .Pe moreproc
|
|
meillo@76
|
700 profile entries, which allowed the user to override the system defaults.
|
|
meillo@74
|
701 Later, the concept was reworked to respect the standard environment
|
|
meillo@74
|
702 variables
|
|
meillo@74
|
703 .Ev VISUAL
|
|
meillo@74
|
704 and
|
|
meillo@74
|
705 .Ev PAGER
|
|
meillo@76
|
706 if they are set.
|
|
meillo@74
|
707 Today, mmh determines the editor to use in the following order,
|
|
meillo@74
|
708 taking the first available and non-empty item:
|
|
meillo@74
|
709 .IP (1)
|
|
meillo@74
|
710 Environment variable
|
|
meillo@74
|
711 .Ev MMHEDITOR
|
|
meillo@74
|
712 .IP (2)
|
|
meillo@74
|
713 Profile entry
|
|
meillo@74
|
714 .Pe Editor
|
|
meillo@74
|
715 .IP (3)
|
|
meillo@74
|
716 Environment variable
|
|
meillo@74
|
717 .Ev VISUAL
|
|
meillo@74
|
718 .IP (4)
|
|
meillo@74
|
719 Environment variable
|
|
meillo@74
|
720 .Ev EDITOR
|
|
meillo@74
|
721 .IP (5)
|
|
meillo@74
|
722 Command
|
|
meillo@74
|
723 .Pn vi .
|
|
meillo@74
|
724 .P
|
|
meillo@76
|
725 .Ci f85f4b7ae62e3d05a945dcd46ead51f0a2a89a9b
|
|
meillo@76
|
726 .P
|
|
meillo@89
|
727 The pager to use is determined in a similar order,
|
|
meillo@74
|
728 also taking the first available and non-empty item:
|
|
meillo@74
|
729 .IP (1)
|
|
meillo@74
|
730 Environment variable
|
|
meillo@74
|
731 .Ev MMHPAGER
|
|
meillo@74
|
732 .IP (2)
|
|
meillo@74
|
733 Profile entry
|
|
meillo@74
|
734 .Pe Pager
|
|
meillo@74
|
735 (replaces
|
|
meillo@74
|
736 .Pe moreproc )
|
|
meillo@74
|
737 .IP (3)
|
|
meillo@74
|
738 Environment variable
|
|
meillo@74
|
739 .Ev PAGER
|
|
meillo@74
|
740 .IP (4)
|
|
meillo@74
|
741 Command
|
|
meillo@74
|
742 .Pn more .
|
|
meillo@74
|
743 .P
|
|
meillo@74
|
744 .Ci 0c4214ea2aec6497d0d67b436bbee9bc1d225f1e
|
|
meillo@74
|
745 .P
|
|
meillo@76
|
746 By respecting the
|
|
meillo@74
|
747 .Ev VISUAL /\c
|
|
meillo@74
|
748 .Ev EDITOR
|
|
meillo@74
|
749 and
|
|
meillo@74
|
750 .Ev PAGER
|
|
meillo@76
|
751 environment variables,
|
|
meillo@76
|
752 the new behavior confirms better to the common style on Unix systems.
|
|
meillo@76
|
753 Additionally, the new approach is more uniform and clearer to users.
|
|
meillo@72
|
754
|
|
meillo@72
|
755
|
|
meillo@76
|
756 .U3 "ndbm
|
|
meillo@72
|
757 .P
|
|
meillo@74
|
758 .Pn slocal
|
|
meillo@78
|
759 used to depend on
|
|
meillo@74
|
760 .I ndbm ,
|
|
meillo@74
|
761 a database library.
|
|
meillo@76
|
762 The database is used to store the `\fLMessage-ID\fP's of all
|
|
meillo@76
|
763 messages delivered.
|
|
meillo@74
|
764 This enables
|
|
meillo@74
|
765 .Pn slocal
|
|
meillo@74
|
766 to suppress delivering the same message to the same user twice.
|
|
meillo@74
|
767 (This features was enabled by the
|
|
meillo@74
|
768 .Sw -suppressdup
|
|
meillo@74
|
769 switch.)
|
|
meillo@74
|
770 .P
|
|
meillo@100
|
771 A variety of versions of the database library exist.
|
|
meillo@78
|
772 .[
|
|
meillo@78
|
773 wolter unix incompat notes dbm
|
|
meillo@78
|
774 .]
|
|
meillo@74
|
775 Complicated autoconf code was needed to detect them correctly.
|
|
meillo@74
|
776 Further more, the configure switches
|
|
meillo@74
|
777 .Sw --with-ndbm=ARG
|
|
meillo@74
|
778 and
|
|
meillo@74
|
779 .Sw --with-ndbmheader=ARG
|
|
meillo@74
|
780 were added to help with difficult setups that would
|
|
meillo@78
|
781 not be detected automatically or correctly.
|
|
meillo@74
|
782 .P
|
|
meillo@74
|
783 By removing the suppress duplicates feature of
|
|
meillo@74
|
784 .Pn slocal ,
|
|
meillo@74
|
785 the dependency on
|
|
meillo@74
|
786 .I ndbm
|
|
meillo@78
|
787 vanished and 120 lines of complex autoconf code could be saved.
|
|
meillo@74
|
788 .Ci ecd6d6a20cb7a1507e3a20d6c4cb3a1cf14c6bbf
|
|
meillo@89
|
789 The change removed functionality too, but that is minor to the
|
|
meillo@78
|
790 improvement by dropping the dependency and the complex autoconf code.
|
|
meillo@72
|
791
|
|
meillo@74
|
792 .U3 "mh-e Support
|
|
meillo@72
|
793 .P
|
|
meillo@74
|
794 The configure option
|
|
meillo@74
|
795 .Sw --disable-mhe
|
|
meillo@74
|
796 was removed when the mh-e support was reworked.
|
|
meillo@74
|
797 Mh-e is the Emacs front-end to MH.
|
|
meillo@76
|
798 It requires MH to provide minor additional functions.
|
|
meillo@76
|
799 The
|
|
meillo@76
|
800 .Sw --disable-mhe
|
|
meillo@76
|
801 configure option could switch these extensions off.
|
|
meillo@76
|
802 After removing the support for old versions of mh-e,
|
|
meillo@74
|
803 only the
|
|
meillo@74
|
804 .Sw -build
|
|
meillo@76
|
805 switches of
|
|
meillo@74
|
806 .Pn forw
|
|
meillo@74
|
807 and
|
|
meillo@74
|
808 .Pn repl
|
|
meillo@76
|
809 are left to be mh-e extensions.
|
|
meillo@76
|
810 They are now always built in because they add little code and complexity.
|
|
meillo@76
|
811 In consequence, the
|
|
meillo@74
|
812 .Sw --disable-mhe
|
|
meillo@76
|
813 configure option was removed
|
|
meillo@72
|
814 .Ci a7ce7b4a580d77b6c2c4d980812beb589aa4c643
|
|
meillo@74
|
815 Removing the option removed a second code setup that would have
|
|
meillo@74
|
816 needed to be tested.
|
|
meillo@76
|
817 This change was first done in nmh and thereafter merged into mmh.
|
|
meillo@76
|
818 .P
|
|
meillo@76
|
819 The interface changes in mmh require mh-e to be adjusted in order
|
|
meillo@76
|
820 to be able to use mmh as back-end.
|
|
meillo@76
|
821 This will require minor changes to mh-e, but removing the
|
|
meillo@76
|
822 .Sw -build
|
|
meillo@76
|
823 switches would require more rework.
|
|
meillo@72
|
824
|
|
meillo@74
|
825 .U3 "Masquerading
|
|
meillo@72
|
826 .P
|
|
meillo@74
|
827 The configure option
|
|
meillo@74
|
828 .Sw --enable-masquerade
|
|
meillo@76
|
829 could take up to three arguments:
|
|
meillo@76
|
830 `draft_from', `mmailid', and `username_extension'.
|
|
meillo@74
|
831 They activated different types of address masquerading.
|
|
meillo@74
|
832 All of them were implemented in the SMTP-speaking
|
|
meillo@74
|
833 .Pn post
|
|
meillo@76
|
834 command, which provided an MSA.
|
|
meillo@76
|
835 Address masquerading is an MTA's task and mmh does not cover
|
|
meillo@76
|
836 this field anymore.
|
|
meillo@76
|
837 Hence, true masquerading needs to be implemented in the external MTA.
|
|
meillo@74
|
838 .P
|
|
meillo@74
|
839 The
|
|
meillo@74
|
840 .I mmailid
|
|
meillo@74
|
841 masquerading type is the oldest one of the three and the only one
|
|
meillo@74
|
842 available in the original MH.
|
|
meillo@74
|
843 It provided a
|
|
meillo@74
|
844 .I username
|
|
meillo@74
|
845 to
|
|
meillo@74
|
846 .I fakeusername
|
|
meillo@76
|
847 mapping, based on the password file's GECOS field.
|
|
meillo@74
|
848 The man page
|
|
meillo@74
|
849 .Mp mh-tailor(5)
|
|
meillo@74
|
850 described the use case as being the following:
|
|
meillo@98
|
851 .QS
|
|
meillo@74
|
852 This is useful if you want the messages you send to always
|
|
meillo@74
|
853 appear to come from the name of an MTA alias rather than your
|
|
meillo@74
|
854 actual account name. For instance, many organizations set up
|
|
meillo@74
|
855 `First.Last' sendmail aliases for all users. If this is
|
|
meillo@74
|
856 the case, the GECOS field for each user should look like:
|
|
meillo@74
|
857 ``First [Middle] Last <First.Last>''
|
|
meillo@98
|
858 .QE
|
|
meillo@74
|
859 .P
|
|
meillo@74
|
860 As mmh sends outgoing mail via the local MTA only,
|
|
meillo@76
|
861 the best location to do such global rewrites is there.
|
|
meillo@74
|
862 Besides, the MTA is conceptionally the right location because it
|
|
meillo@74
|
863 does the reverse mapping for incoming mail (aliasing), too.
|
|
meillo@76
|
864 Further more, masquerading set up there is readily available for all
|
|
meillo@74
|
865 mail software on the system.
|
|
meillo@76
|
866 Hence, mmailid masquerading was removed.
|
|
meillo@74
|
867 .Ci 0836c8000ccb34b59410ef1c15b1b7feac70ce5f
|
|
meillo@74
|
868 .P
|
|
meillo@74
|
869 The
|
|
meillo@74
|
870 .I username_extension
|
|
meillo@76
|
871 masquerading type did not replace the username but would append a suffix,
|
|
meillo@76
|
872 specified by the
|
|
meillo@74
|
873 .Ev USERNAME_EXTENSION
|
|
meillo@76
|
874 environment variable, to it.
|
|
meillo@76
|
875 This provided support for the
|
|
meillo@74
|
876 .I user-extension
|
|
meillo@74
|
877 feature of qmail and the similar
|
|
meillo@74
|
878 .I "plussed user
|
|
meillo@74
|
879 processing of sendmail.
|
|
meillo@74
|
880 The decision to remove this username_extension masquerading was
|
|
meillo@74
|
881 motivated by the fact that
|
|
meillo@74
|
882 .Pn spost
|
|
meillo@76
|
883 hadn't supported it already.
|
|
meillo@76
|
884 .Ci 2abae0bfd0ad5bf898461e50aa4b466d641f23d9
|
|
meillo@76
|
885 Username extensions are possible in mmh, but less convenient to use.
|
|
meillo@76
|
886 .\" XXX format file %(getenv USERNAME_EXTENSION)
|
|
meillo@74
|
887 .P
|
|
meillo@74
|
888 The
|
|
meillo@74
|
889 .I draft_from
|
|
meillo@74
|
890 masquerading type instructed
|
|
meillo@74
|
891 .Pn post
|
|
meillo@84
|
892 to use the value of the
|
|
meillo@84
|
893 .Hd From
|
|
meillo@84
|
894 header field as SMTP envelope sender.
|
|
meillo@76
|
895 Sender addresses could be replaced completely.
|
|
meillo@74
|
896 .Ci b14ea6073f77b4359aaf3fddd0e105989db9
|
|
meillo@76
|
897 Mmh offers a kind of masquerading similar in effect, but
|
|
meillo@74
|
898 with technical differences.
|
|
meillo@76
|
899 As mmh does not transfer messages itself, the local MTA has final control
|
|
meillo@76
|
900 over the sender's address. Any masquerading mmh introduces may be reverted
|
|
meillo@76
|
901 by the MTA.
|
|
meillo@76
|
902 In times of pedantic spam checking, an MTA will take care to use
|
|
meillo@76
|
903 sensible envelope sender addresses to keep its own reputation up.
|
|
meillo@84
|
904 Nonetheless, the MUA can set the
|
|
meillo@84
|
905 .Hd From
|
|
meillo@84
|
906 header field and thereby propose
|
|
meillo@76
|
907 a sender address to the MTA.
|
|
meillo@74
|
908 The MTA may then decide to take that one or generate the canonical sender
|
|
meillo@74
|
909 address for use as envelope sender address.
|
|
meillo@74
|
910 .P
|
|
meillo@74
|
911 In mmh, the MTA will always extract the recipient and sender from the
|
|
meillo@84
|
912 message header (\c
|
|
meillo@74
|
913 .Pn sendmail 's
|
|
meillo@74
|
914 .Sw -t
|
|
meillo@74
|
915 switch).
|
|
meillo@84
|
916 The
|
|
meillo@84
|
917 .Hd From
|
|
meillo@84
|
918 header field of the draft may be set arbitrary by the user.
|
|
meillo@74
|
919 If it is missing, the canonical sender address will be generated by the MTA.
|
|
meillo@74
|
920
|
|
meillo@74
|
921 .U3 "Remaining Options
|
|
meillo@74
|
922 .P
|
|
meillo@74
|
923 Two configure options remain in mmh.
|
|
meillo@74
|
924 One is the locking method to use:
|
|
meillo@74
|
925 .Sw --with-locking=[dot|fcntl|flock|lockf] .
|
|
meillo@76
|
926 The idea of removing all methods except the portable dot locking
|
|
meillo@76
|
927 and having that one as the default is appealing, but this change
|
|
meillo@76
|
928 requires deeper technical investigation into the topic.
|
|
meillo@76
|
929 The other option,
|
|
meillo@74
|
930 .Sw --enable-debug ,
|
|
meillo@74
|
931 compiles the programs with debugging symbols and does not strip them.
|
|
meillo@74
|
932 This option is likely to stay.
|
|
meillo@72
|
933
|
|
meillo@72
|
934
|
|
meillo@58
|
935
|
|
meillo@63
|
936
|
|
meillo@100
|
937 .H2 "Command Line Switches
|
|
meillo@58
|
938 .P
|
|
meillo@93
|
939 The command line switches of MH tools follow the X Window style.
|
|
meillo@93
|
940 They are words, introduced by a single dash.
|
|
meillo@93
|
941 For example:
|
|
meillo@93
|
942 .Cl "-truncate" .
|
|
meillo@93
|
943 Every program in mmh has two generic switches:
|
|
meillo@93
|
944 .Sw -help ,
|
|
meillo@93
|
945 to print a short message on how to use the program, and
|
|
meillo@93
|
946 .Sw -Version ,
|
|
meillo@93
|
947 to tell what version of mmh the program belongs to.
|
|
meillo@93
|
948 .P
|
|
meillo@93
|
949 Switches change the behavior of programs.
|
|
meillo@93
|
950 Programs that do one thing in one way require no switches.
|
|
meillo@93
|
951 In most cases, doing something in exactly one way is too limiting.
|
|
meillo@97
|
952 If there is basically one task to accomplish, but it should be done
|
|
meillo@93
|
953 in various ways, switches are a good approach to alter the behavior
|
|
meillo@93
|
954 of a program.
|
|
meillo@93
|
955 Changing the behavior of programs provides flexibility and customization
|
|
meillo@97
|
956 to users, but at the same time it complicates the code, documentation and
|
|
meillo@93
|
957 usage of the program.
|
|
meillo@97
|
958 .\" XXX: Ref
|
|
meillo@93
|
959 Therefore, the number of switches should be kept small.
|
|
meillo@93
|
960 A small set of well-chosen switches does no harm.
|
|
meillo@93
|
961 But usually, the number of switches increases over time.
|
|
meillo@93
|
962 Already in 1985, Rose and Romine have identified this as a major
|
|
meillo@93
|
963 problem of MH:
|
|
meillo@93
|
964 .[ [
|
|
meillo@93
|
965 rose romine real work
|
|
meillo@93
|
966 .], p. 12]
|
|
meillo@98
|
967 .QS
|
|
meillo@93
|
968 A complaint often heard about systems which undergo substantial development
|
|
meillo@93
|
969 by many people over a number of years, is that more and more options are
|
|
meillo@93
|
970 introduced which add little to the functionality but greatly increase the
|
|
meillo@93
|
971 amount of information a user needs to know in order to get useful work done.
|
|
meillo@93
|
972 This is usually referred to as creeping featurism.
|
|
meillo@93
|
973 .QP
|
|
meillo@93
|
974 Unfortunately MH, having undergone six years of off-and-on development by
|
|
meillo@93
|
975 ten or so well-meaning programmers (the present authors included),
|
|
meillo@93
|
976 suffers mightily from this.
|
|
meillo@98
|
977 .QE
|
|
meillo@93
|
978 .P
|
|
meillo@97
|
979 Being reluctant to adding new switches \(en or `options',
|
|
meillo@97
|
980 as Rose and Romine call them \(en is one part of a counter-action,
|
|
meillo@97
|
981 the other part is removing hardly used switches.
|
|
meillo@97
|
982 Nmh's tools had lots of switches already implemented,
|
|
meillo@97
|
983 hence, cleaning up by removing some of them was the more important part
|
|
meillo@97
|
984 of the counter-action.
|
|
meillo@93
|
985 Removing existing functionality is always difficult because it
|
|
meillo@93
|
986 breaks programs that use these functions.
|
|
meillo@93
|
987 Also, for every obsolete feature, there'll always be someone who still
|
|
meillo@93
|
988 uses it and thus opposes its removal.
|
|
meillo@93
|
989 This puts the developer into the position,
|
|
meillo@93
|
990 where sensible improvements to style are regarded as destructive acts.
|
|
meillo@97
|
991 Yet, living with the featurism is far worse, in my eyes, because
|
|
meillo@97
|
992 future needs will demand adding further features,
|
|
meillo@93
|
993 worsening the situation more and more.
|
|
meillo@93
|
994 Rose and Romine added in a footnote,
|
|
meillo@93
|
995 ``[...]
|
|
meillo@93
|
996 .Pn send
|
|
meillo@93
|
997 will no doubt acquire an endless number of switches in the years to come.''
|
|
meillo@97
|
998 Although clearly humorous, the comment points to the nature of the problem.
|
|
meillo@97
|
999 Refusing to add any new switches would encounter the problem at its root,
|
|
meillo@97
|
1000 but this is not practical.
|
|
meillo@97
|
1001 New needs will require new switches and it would be unwise to block
|
|
meillo@97
|
1002 them strictly.
|
|
meillo@97
|
1003 Nevertheless, removing obsolete switches still is an effective approach
|
|
meillo@97
|
1004 to deal with the problem.
|
|
meillo@97
|
1005 Working on an experimental branch without an established user base,
|
|
meillo@97
|
1006 eased my work because I did not offend users when I removed existing
|
|
meillo@97
|
1007 funtions.
|
|
meillo@93
|
1008 .P
|
|
meillo@93
|
1009 Rose and Romine counted 24 visible and 9 more hidden switches for
|
|
meillo@93
|
1010 .Pn send .
|
|
meillo@97
|
1011 In nmh, they increased up to 32 visible and 12 hidden ones.
|
|
meillo@97
|
1012 At the time of writing, no more than 7 visible switches and 1 hidden switch
|
|
meillo@97
|
1013 have remained in mmh's
|
|
meillo@97
|
1014 .Pn send .
|
|
meillo@97
|
1015 (These numbers include two generic switches, help and version.)
|
|
meillo@93
|
1016 .P
|
|
meillo@97
|
1017 Fig. XXX
|
|
meillo@93
|
1018 .\" XXX Ref
|
|
meillo@97
|
1019 displays the number of switches for each of the tools that is available
|
|
meillo@97
|
1020 in both, nmh and mmh.
|
|
meillo@100
|
1021 The tools are sorted by the number of switches they had in nmh.
|
|
meillo@100
|
1022 Visible and hidden switches were counted,
|
|
meillo@97
|
1023 but not the generic help and version switches.
|
|
meillo@93
|
1024 Whereas in the beginning of the project, the average tool had 11 switches,
|
|
meillo@93
|
1025 now it has no more than 5 \(en only half as many.
|
|
meillo@93
|
1026 If the `no' switches and similar inverse variant are folded onto
|
|
meillo@100
|
1027 their counter-parts, the average tool had 8 switches in pre-mmh times and
|
|
meillo@100
|
1028 has 4 now.
|
|
meillo@93
|
1029 The total number of functional switches in mmh dropped from 465
|
|
meillo@93
|
1030 to 234.
|
|
meillo@58
|
1031
|
|
meillo@93
|
1032 .KS
|
|
meillo@93
|
1033 .in 1c
|
|
meillo@93
|
1034 .so input/switches.grap
|
|
meillo@93
|
1035 .KE
|
|
meillo@58
|
1036
|
|
meillo@93
|
1037 .P
|
|
meillo@93
|
1038 A part of the switches vanished after functions were removed.
|
|
meillo@93
|
1039 This was the case for network mail transfer, for instance.
|
|
meillo@97
|
1040 Sometimes, however, the work flow was the other way:
|
|
meillo@97
|
1041 I looked through the
|
|
meillo@97
|
1042 .Mp mh-chart (7)
|
|
meillo@97
|
1043 man page to identify the tools with apparently too many switches.
|
|
meillo@97
|
1044 Then considering the value of each of the switches by examining
|
|
meillo@97
|
1045 the tool's man page and source code, aided by recherche and testing.
|
|
meillo@97
|
1046 This way, the removal of functions was suggested by the aim to reduce
|
|
meillo@97
|
1047 the number of switches per command.
|
|
meillo@97
|
1048
|
|
meillo@58
|
1049
|
|
meillo@93
|
1050 .U3 "Draft Folder Facility
|
|
meillo@93
|
1051 .P
|
|
meillo@100
|
1052 A change early in the project was the complete transition from
|
|
meillo@93
|
1053 the single draft message to the draft folder facility.
|
|
meillo@97
|
1054 .Ci 337338b404931f06f0db2119c9e145e8ca5a9860
|
|
meillo@100
|
1055 The draft folder facility was introduced in the mid-Eighties, when
|
|
meillo@100
|
1056 Rose and Romine called it a ``relatively new feature''.
|
|
meillo@93
|
1057 .[
|
|
meillo@93
|
1058 rose romine real work
|
|
meillo@93
|
1059 .]
|
|
meillo@97
|
1060 Since then, the facility had existed but was deactivated by default.
|
|
meillo@93
|
1061 The default activation and the related rework of the tools made it
|
|
meillo@93
|
1062 possible to remove the
|
|
meillo@93
|
1063 .Sw -[no]draftfolder ,
|
|
meillo@93
|
1064 and
|
|
meillo@93
|
1065 .Sw -draftmessage
|
|
meillo@93
|
1066 switches from
|
|
meillo@93
|
1067 .Pn comp ,
|
|
meillo@93
|
1068 .Pn repl ,
|
|
meillo@93
|
1069 .Pn forw ,
|
|
meillo@93
|
1070 .Pn dist ,
|
|
meillo@93
|
1071 .Pn whatnow ,
|
|
meillo@93
|
1072 and
|
|
meillo@93
|
1073 .Pn send .
|
|
meillo@97
|
1074 .Ci 337338b404931f06f0db2119c9e145e8ca5a9860
|
|
meillo@97
|
1075 The only flexibility removed with this change is having multiple
|
|
meillo@97
|
1076 draft folders within one profile.
|
|
meillo@97
|
1077 I consider this a theoretical problem only.
|
|
meillo@93
|
1078 In the same go, the
|
|
meillo@93
|
1079 .Sw -draft
|
|
meillo@93
|
1080 switch of
|
|
meillo@93
|
1081 .Pn anno ,
|
|
meillo@93
|
1082 .Pn refile ,
|
|
meillo@93
|
1083 and
|
|
meillo@93
|
1084 .Pn send
|
|
meillo@93
|
1085 was removed.
|
|
meillo@93
|
1086 The special-casing of `the' draft message became irrelevant after
|
|
meillo@93
|
1087 the rework of the draft system.
|
|
meillo@93
|
1088 (See Sec. XXX.)
|
|
meillo@95
|
1089 Equally,
|
|
meillo@95
|
1090 .Pn comp
|
|
meillo@95
|
1091 lost its
|
|
meillo@95
|
1092 .Sw -file
|
|
meillo@95
|
1093 switch.
|
|
meillo@95
|
1094 The draft folder facility, together with the
|
|
meillo@95
|
1095 .Sw -form
|
|
meillo@95
|
1096 switch, are sufficient.
|
|
meillo@93
|
1097
|
|
meillo@95
|
1098
|
|
meillo@102
|
1099 .U3 "In Place Editing
|
|
meillo@93
|
1100 .P
|
|
meillo@93
|
1101 .Pn anno
|
|
meillo@93
|
1102 had the switches
|
|
meillo@93
|
1103 .Sw -[no]inplace
|
|
meillo@100
|
1104 to either annotate the message in place and thus preserve hard links,
|
|
meillo@93
|
1105 or annotate a copy to replace the original message, breaking hard links.
|
|
meillo@97
|
1106 Following the assumption that linked messages should truly be the
|
|
meillo@97
|
1107 same message, and annotating it should not break the link, the
|
|
meillo@93
|
1108 .Sw -[no]inplace
|
|
meillo@93
|
1109 switches were removed and the previous default
|
|
meillo@93
|
1110 .Sw -inplace
|
|
meillo@93
|
1111 was made the only behavior.
|
|
meillo@97
|
1112 .Ci c8195849d2e366c569271abb0f5f60f4ebf0b4d0
|
|
meillo@93
|
1113 The
|
|
meillo@93
|
1114 .Sw -[no]inplace
|
|
meillo@93
|
1115 switches of
|
|
meillo@93
|
1116 .Pn repl ,
|
|
meillo@93
|
1117 .Pn forw ,
|
|
meillo@93
|
1118 and
|
|
meillo@93
|
1119 .Pn dist
|
|
meillo@93
|
1120 could be removed, too, as they were simply passed through to
|
|
meillo@93
|
1121 .Pn anno .
|
|
meillo@93
|
1122 .P
|
|
meillo@93
|
1123 .Pn burst
|
|
meillo@93
|
1124 also had
|
|
meillo@93
|
1125 .Sw -[no]inplace
|
|
meillo@95
|
1126 switches, but with different meaning.
|
|
meillo@95
|
1127 With
|
|
meillo@95
|
1128 .Sw -inplace ,
|
|
meillo@95
|
1129 the digest had been replaced by the table of contents (i.e. the
|
|
meillo@95
|
1130 introduction text) and the bursted messages were placed right
|
|
meillo@95
|
1131 after this message, renumbering all following messages.
|
|
meillo@95
|
1132 Also, any trailing text of the digest was lost, though,
|
|
meillo@95
|
1133 in practice, it usually consists of an end-of-digest marker only.
|
|
meillo@95
|
1134 Nontheless, this behavior appeared less elegant than the
|
|
meillo@95
|
1135 .Sw -noinplace
|
|
meillo@95
|
1136 behavior, which already had been the default.
|
|
meillo@95
|
1137 Nmh's
|
|
meillo@95
|
1138 .Mp burst (1)
|
|
meillo@95
|
1139 man page reads:
|
|
meillo@95
|
1140 .sp \n(PDu
|
|
meillo@98
|
1141 .QS
|
|
meillo@93
|
1142 If -noinplace is given, each digest is preserved, no table
|
|
meillo@93
|
1143 of contents is produced, and the messages contained within
|
|
meillo@93
|
1144 the digest are placed at the end of the folder. Other messages
|
|
meillo@93
|
1145 are not tampered with in any way.
|
|
meillo@98
|
1146 .QE
|
|
meillo@95
|
1147 .LP
|
|
meillo@93
|
1148 The decision to drop the
|
|
meillo@93
|
1149 .Sw -inplace
|
|
meillo@95
|
1150 behavior was supported by the code complexity and the possible data loss
|
|
meillo@95
|
1151 it caused.
|
|
meillo@93
|
1152 .Sw -noinplace
|
|
meillo@95
|
1153 was chosen to be the definitive behavior.
|
|
meillo@97
|
1154 .Ci 68a686adeb39223a5e1ad35e4a24890ec053679d
|
|
meillo@93
|
1155
|
|
meillo@95
|
1156
|
|
meillo@95
|
1157 .U3 "Forms and Format Strings
|
|
meillo@93
|
1158 .P
|
|
meillo@95
|
1159 Historically, the tools that had
|
|
meillo@95
|
1160 .Sw -form
|
|
meillo@95
|
1161 switches to supply a form file had
|
|
meillo@95
|
1162 .Sw -format
|
|
meillo@95
|
1163 switches as well to supply the contents of a form file as a string
|
|
meillo@95
|
1164 on the command line directly.
|
|
meillo@95
|
1165 In consequence, the following two lines equaled:
|
|
meillo@95
|
1166 .VS
|
|
meillo@95
|
1167 scan -form scan.mailx
|
|
meillo@95
|
1168 scan -format "`cat .../scan.mailx`"
|
|
meillo@95
|
1169 VE
|
|
meillo@95
|
1170 The
|
|
meillo@95
|
1171 .Sw -format
|
|
meillo@95
|
1172 switches were dropped in favor for extending the
|
|
meillo@95
|
1173 .Sw -form
|
|
meillo@95
|
1174 switches.
|
|
meillo@97
|
1175 .Ci f51956be123db66b00138f80464d06f030dbb88d
|
|
meillo@95
|
1176 If their argument starts with an equal sign (`='),
|
|
meillo@95
|
1177 then the rest of the argument is taken as a format string,
|
|
meillo@95
|
1178 otherwise the arguments is treated as the name of a format file.
|
|
meillo@95
|
1179 Thus, now the following two lines equal:
|
|
meillo@95
|
1180 .VS
|
|
meillo@95
|
1181 scan -form scan.mailx
|
|
meillo@95
|
1182 scan -form "=`cat .../scan.mailx`"
|
|
meillo@95
|
1183 VE
|
|
meillo@95
|
1184 This rework removed the prefix collision between
|
|
meillo@95
|
1185 .Sw -form
|
|
meillo@95
|
1186 and
|
|
meillo@95
|
1187 .Sw -format .
|
|
meillo@95
|
1188 Now, typing
|
|
meillo@95
|
1189 .Sw -fo
|
|
meillo@95
|
1190 suffices to specify form or format string.
|
|
meillo@95
|
1191 .P
|
|
meillo@95
|
1192 The different meaning of
|
|
meillo@95
|
1193 .Sw -format
|
|
meillo@95
|
1194 for
|
|
meillo@95
|
1195 .Pn repl
|
|
meillo@95
|
1196 and
|
|
meillo@95
|
1197 .Pn forw
|
|
meillo@95
|
1198 was removed in mmh.
|
|
meillo@95
|
1199 .Pn forw
|
|
meillo@95
|
1200 was completely switched to MIME-type forwarding, thus removing the
|
|
meillo@95
|
1201 .Sw -[no]format .
|
|
meillo@97
|
1202 .Ci 6e271608b7b9c23771523f88d23a4d3593010cf1
|
|
meillo@95
|
1203 For
|
|
meillo@95
|
1204 .Pn repl ,
|
|
meillo@95
|
1205 the
|
|
meillo@95
|
1206 .Sw -[no]format
|
|
meillo@95
|
1207 switches were reworked to
|
|
meillo@95
|
1208 .Sw -[no]filter
|
|
meillo@95
|
1209 switches.
|
|
meillo@97
|
1210 .Ci 67411b1f95d6ec987b4c732459e1ba8a8ac192c6
|
|
meillo@95
|
1211 The
|
|
meillo@95
|
1212 .Sw -format
|
|
meillo@95
|
1213 switches of
|
|
meillo@95
|
1214 .Pn send
|
|
meillo@95
|
1215 and
|
|
meillo@95
|
1216 .Pn post ,
|
|
meillo@95
|
1217 which had a third meaning,
|
|
meillo@95
|
1218 were removed likewise.
|
|
meillo@97
|
1219 .Ci f3cb7cde0e6f10451b6848678d95860d512224b9
|
|
meillo@95
|
1220 Eventually, the ambiguity of the
|
|
meillo@95
|
1221 .Sw -format
|
|
meillo@95
|
1222 switches was resolved by not anymore having any such switch in mmh.
|
|
meillo@95
|
1223
|
|
meillo@95
|
1224
|
|
meillo@95
|
1225 .U3 "MIME Tools
|
|
meillo@95
|
1226 .P
|
|
meillo@95
|
1227 The MIME tools, which were once part of
|
|
meillo@100
|
1228 .Pn mhn
|
|
meillo@100
|
1229 [sic!],
|
|
meillo@95
|
1230 had several switches that added little practical value to the programs.
|
|
meillo@95
|
1231 The
|
|
meillo@95
|
1232 .Sw -[no]realsize
|
|
meillo@95
|
1233 switches of
|
|
meillo@95
|
1234 .Pn mhbuild
|
|
meillo@95
|
1235 and
|
|
meillo@95
|
1236 .Pn mhlist
|
|
meillo@97
|
1237 were removed, doing real size calculations always now
|
|
meillo@97
|
1238 .Ci 8d8f1c3abc586c005c904e52c4adbfe694d2201c ,
|
|
meillo@97
|
1239 as
|
|
meillo@95
|
1240 ``This provides an accurate count at the expense of a small delay.''
|
|
meillo@95
|
1241 This small delay is not noticable on modern systems.
|
|
meillo@95
|
1242 .P
|
|
meillo@95
|
1243 The
|
|
meillo@95
|
1244 .Sw -[no]check
|
|
meillo@95
|
1245 switches were removed together with the support for
|
|
meillo@95
|
1246 .Hd Content-MD5
|
|
meillo@95
|
1247 header fields.
|
|
meillo@95
|
1248 .[
|
|
meillo@95
|
1249 rfc 1864
|
|
meillo@95
|
1250 .]
|
|
meillo@97
|
1251 .Ci 31dc797eb5178970d68962ca8939da3fd9a8efda
|
|
meillo@95
|
1252 (See Sec. XXX)
|
|
meillo@95
|
1253 .P
|
|
meillo@95
|
1254 The
|
|
meillo@95
|
1255 .Sw -[no]ebcdicsafe
|
|
meillo@95
|
1256 and
|
|
meillo@95
|
1257 .Sw -[no]rfc934mode
|
|
meillo@95
|
1258 switches of
|
|
meillo@95
|
1259 .Pn mhbuild
|
|
meillo@95
|
1260 were removed because they are considered obsolete.
|
|
meillo@97
|
1261 .Ci 01a3480928da485b4d6109d36d751dfa71799d58
|
|
meillo@97
|
1262 .Ci 3363e2624dce0eb8164cf8b3f1ab385c8ff72e88
|
|
meillo@95
|
1263 .P
|
|
meillo@95
|
1264 Content caching of external MIME parts, activated with the
|
|
meillo@95
|
1265 .Sw -rcache
|
|
meillo@95
|
1266 and
|
|
meillo@95
|
1267 .Sw -wcache
|
|
meillo@95
|
1268 switches was completely removed.
|
|
meillo@97
|
1269 .Ci d1fefd9f614e4dc3cda16da6c69133c1b2005269
|
|
meillo@97
|
1270 External MIME parts are rare today, having a caching facility
|
|
meillo@96
|
1271 for them is appears to be unnecessary.
|
|
meillo@95
|
1272 .P
|
|
meillo@95
|
1273 In pre-MIME times,
|
|
meillo@95
|
1274 .Pn mhl
|
|
meillo@95
|
1275 had covered many tasks that are part of MIME handling today.
|
|
meillo@95
|
1276 Therefore,
|
|
meillo@95
|
1277 .Pn mhl
|
|
meillo@95
|
1278 could be simplified to a large extend, reducing the number of its
|
|
meillo@95
|
1279 switches from 21 to 6.
|
|
meillo@97
|
1280 .Ci 350ad6d3542a07639213cf2a4fe524e829c1e7b6
|
|
meillo@97
|
1281 .Ci 0e46503be3c855bddaeae3843e1b659279c35d70
|
|
meillo@95
|
1282
|
|
meillo@95
|
1283
|
|
meillo@95
|
1284 .U3 "Mail Transfer Switches
|
|
meillo@95
|
1285 .P
|
|
meillo@95
|
1286 With the removal of the mail transfer facilities, a lot of switches
|
|
meillo@95
|
1287 vanished automatically.
|
|
meillo@95
|
1288 .Pn inc
|
|
meillo@95
|
1289 lost 9 switches, namely
|
|
meillo@95
|
1290 .Sw -host ,
|
|
meillo@95
|
1291 .Sw -port ,
|
|
meillo@95
|
1292 .Sw -user ,
|
|
meillo@95
|
1293 .Sw -proxy ,
|
|
meillo@95
|
1294 .Sw -snoop ,
|
|
meillo@95
|
1295 .Sw -[no]pack ,
|
|
meillo@95
|
1296 as well as
|
|
meillo@95
|
1297 .Sw -sasl
|
|
meillo@95
|
1298 and
|
|
meillo@95
|
1299 .Sw -saslmech .
|
|
meillo@95
|
1300 .Pn send
|
|
meillo@95
|
1301 and
|
|
meillo@95
|
1302 .Pn post
|
|
meillo@95
|
1303 lost 11 switches each, namely
|
|
meillo@95
|
1304 .Sw -server ,
|
|
meillo@95
|
1305 .Sw -port ,
|
|
meillo@95
|
1306 .Sw -client ,
|
|
meillo@95
|
1307 .Sw -user ,
|
|
meillo@95
|
1308 .Sw -mail ,
|
|
meillo@95
|
1309 .Sw -saml ,
|
|
meillo@95
|
1310 .Sw -send ,
|
|
meillo@95
|
1311 .Sw -soml ,
|
|
meillo@95
|
1312 .Sw -snoop ,
|
|
meillo@95
|
1313 as well as
|
|
meillo@95
|
1314 .Sw -sasl ,
|
|
meillo@95
|
1315 .Sw -saslmech ,
|
|
meillo@95
|
1316 and
|
|
meillo@95
|
1317 .Sw -tls .
|
|
meillo@95
|
1318 .Pn send
|
|
meillo@95
|
1319 had the switches only to pass them further to
|
|
meillo@95
|
1320 .Pn post ,
|
|
meillo@95
|
1321 because the user would invoke
|
|
meillo@95
|
1322 .Pn post
|
|
meillo@95
|
1323 not directly, but through
|
|
meillo@95
|
1324 .Pn send .
|
|
meillo@95
|
1325 All these switches, except
|
|
meillo@95
|
1326 .Sw -snoop
|
|
meillo@95
|
1327 were usually defined as default switches in the user's profile,
|
|
meillo@95
|
1328 but hardly given in interactive usage.
|
|
meillo@95
|
1329 .P
|
|
meillo@95
|
1330 Of course, those switches did not really ``vanish'', but the configuration
|
|
meillo@95
|
1331 they did was handed over to external MSAs and MRAs.
|
|
meillo@95
|
1332 Instead of setting up the mail transfer in mmh, it is set up in
|
|
meillo@95
|
1333 external tools.
|
|
meillo@95
|
1334 Yet, this simplifies mmh.
|
|
meillo@95
|
1335 Specialized external tools will likely have simple configuration files.
|
|
meillo@95
|
1336 Hence, instead of having one complicated central configuration file,
|
|
meillo@95
|
1337 the configuration of each domain is separate.
|
|
meillo@95
|
1338 Although the user needs to learn to configure each of the tools,
|
|
meillo@95
|
1339 each configuration is likely much simpler.
|
|
meillo@95
|
1340
|
|
meillo@95
|
1341
|
|
meillo@95
|
1342 .U3 "Maildrop Formats
|
|
meillo@95
|
1343 .P
|
|
meillo@95
|
1344 With the removal of MMDF maildrop format support,
|
|
meillo@95
|
1345 .Pn packf
|
|
meillo@95
|
1346 and
|
|
meillo@95
|
1347 .Pn rcvpack
|
|
meillo@95
|
1348 no longer needed their
|
|
meillo@95
|
1349 .Sw -mbox
|
|
meillo@95
|
1350 and
|
|
meillo@95
|
1351 .Sw -mmdf
|
|
meillo@95
|
1352 switches.
|
|
meillo@95
|
1353 .Sw -mbox
|
|
meillo@95
|
1354 is the sole behavior now.
|
|
meillo@97
|
1355 .Ci 3916ab66ad5d183705ac12357621ea8661afd3c0
|
|
meillo@95
|
1356 In the same go,
|
|
meillo@95
|
1357 .Pn packf
|
|
meillo@97
|
1358 and
|
|
meillo@97
|
1359 .Pn rcvpack
|
|
meillo@97
|
1360 were reworked (see Sec. XXX) and their
|
|
meillo@95
|
1361 .Sw -file
|
|
meillo@95
|
1362 switch became unnecessary.
|
|
meillo@97
|
1363 .Ci ca1023716d4c2ab890696f3e41fa0d94267a940e
|
|
meillo@95
|
1364
|
|
meillo@95
|
1365
|
|
meillo@95
|
1366 .U3 "Terminal Magic
|
|
meillo@95
|
1367 .P
|
|
meillo@95
|
1368 Mmh's tools will no longer clear the screen (\c
|
|
meillo@95
|
1369 .Pn scan 's
|
|
meillo@95
|
1370 and
|
|
meillo@95
|
1371 .Pn mhl 's
|
|
meillo@95
|
1372 .Sw -[no]clear
|
|
meillo@97
|
1373 switches
|
|
meillo@97
|
1374 .Ci e57b17343dcb3ff373ef4dd089fbe778f0c7c270
|
|
meillo@97
|
1375 .Ci 943765e7ac5693ae177fd8d2b5a2440e53ce816e ).
|
|
meillo@95
|
1376 Neither will
|
|
meillo@95
|
1377 .Pn mhl
|
|
meillo@95
|
1378 ring the bell (\c
|
|
meillo@97
|
1379 .Sw -[no]bell
|
|
meillo@97
|
1380 .Ci e11983f44e59d8de236affa5b0d0d3067c192e24 )
|
|
meillo@95
|
1381 nor page the output itself (\c
|
|
meillo@97
|
1382 .Sw -length
|
|
meillo@97
|
1383 .Ci 5b9d883db0318ed2b84bb82dee880d7381f99188 ).
|
|
meillo@95
|
1384 .P
|
|
meillo@95
|
1385 Generally, the pager to use is no longer specified with the
|
|
meillo@95
|
1386 .Sw -[no]moreproc
|
|
meillo@95
|
1387 command line switches for
|
|
meillo@95
|
1388 .Pn mhl
|
|
meillo@95
|
1389 and
|
|
meillo@95
|
1390 .Pn show /\c
|
|
meillo@95
|
1391 .Pn mhshow .
|
|
meillo@97
|
1392 .Ci 39e87a75b5c2d3572ec72e717720b44af291e88a
|
|
meillo@95
|
1393 .P
|
|
meillo@95
|
1394 .Pn prompter
|
|
meillo@95
|
1395 lost its
|
|
meillo@95
|
1396 .Sw -erase
|
|
meillo@95
|
1397 and
|
|
meillo@95
|
1398 .Sw -kill
|
|
meillo@95
|
1399 switches because today the terminal cares for the line editing keys.
|
|
meillo@95
|
1400
|
|
meillo@95
|
1401
|
|
meillo@95
|
1402 .U3 "Header Printing
|
|
meillo@95
|
1403 .P
|
|
meillo@95
|
1404 .Pn folder 's
|
|
meillo@95
|
1405 data output is self-explaining enough that
|
|
meillo@95
|
1406 displaying the header line makes few sense.
|
|
meillo@95
|
1407 Hence, the
|
|
meillo@95
|
1408 .Sw -[no]header
|
|
meillo@95
|
1409 switch was removed and headers are never printed.
|
|
meillo@97
|
1410 .Ci 601cc73d1fa05ce96faa728f036d6c51b91701c7
|
|
meillo@95
|
1411 .P
|
|
meillo@95
|
1412 In
|
|
meillo@95
|
1413 .Pn mhlist ,
|
|
meillo@95
|
1414 the
|
|
meillo@95
|
1415 .Sw -[no]header
|
|
meillo@95
|
1416 switches were removed, too.
|
|
meillo@97
|
1417 .Ci b24f96523aaf60e44e04a3ffb1d22e69a13a602f
|
|
meillo@95
|
1418 But in this case headers are always printed,
|
|
meillo@95
|
1419 because the output is not self-explaining.
|
|
meillo@95
|
1420 .P
|
|
meillo@95
|
1421 .Pn scan
|
|
meillo@95
|
1422 also had
|
|
meillo@95
|
1423 .Sw -[no]header
|
|
meillo@95
|
1424 switches.
|
|
meillo@95
|
1425 Printing the header had been sensible until the introduction of
|
|
meillo@95
|
1426 format strings made it impossible to display the column headings.
|
|
meillo@95
|
1427 Only the folder name and the current date remained to be printed.
|
|
meillo@95
|
1428 As this information can be perfectly retrieved by
|
|
meillo@95
|
1429 .Pn folder
|
|
meillo@95
|
1430 and
|
|
meillo@95
|
1431 .Pn date ,
|
|
meillo@95
|
1432 consequently, the switches were removed.
|
|
meillo@97
|
1433 .Ci c477dc5d1d03fa6d9a8ab3dd3508c63cbddc044e
|
|
meillo@95
|
1434 .P
|
|
meillo@95
|
1435 By removing all
|
|
meillo@95
|
1436 .Sw -header
|
|
meillo@95
|
1437 switches, the collision with
|
|
meillo@95
|
1438 .Sw -help
|
|
meillo@95
|
1439 on the first two letters was resolved.
|
|
meillo@95
|
1440 Currently,
|
|
meillo@95
|
1441 .Sw -h
|
|
meillo@95
|
1442 evaluates to
|
|
meillo@95
|
1443 .Sw -help
|
|
meillo@95
|
1444 for all tools of mmh.
|
|
meillo@95
|
1445
|
|
meillo@95
|
1446
|
|
meillo@95
|
1447 .U3 "Suppressing Edits or the WhatNow Shell
|
|
meillo@95
|
1448 .P
|
|
meillo@95
|
1449 The
|
|
meillo@95
|
1450 .Sw -noedit
|
|
meillo@100
|
1451 switch of
|
|
meillo@95
|
1452 .Pn comp ,
|
|
meillo@95
|
1453 .Pn repl ,
|
|
meillo@95
|
1454 .Pn forw ,
|
|
meillo@95
|
1455 .Pn dist ,
|
|
meillo@95
|
1456 and
|
|
meillo@95
|
1457 .Pn whatnow
|
|
meillo@95
|
1458 was removed, but it can now be replaced by specifying
|
|
meillo@95
|
1459 .Sw -editor
|
|
meillo@95
|
1460 with an empty argument.
|
|
meillo@97
|
1461 .Ci 75fca31a5b9d5c1a99c74ab14c94438d8852fba9
|
|
meillo@95
|
1462 (Specifying
|
|
meillo@95
|
1463 .Cl "-editor true
|
|
meillo@95
|
1464 is nearly the same, only differing by the previous editor being set.)
|
|
meillo@95
|
1465 .P
|
|
meillo@95
|
1466 The more important change is the removal of the
|
|
meillo@95
|
1467 .Sw -nowhatnowproc
|
|
meillo@95
|
1468 switch.
|
|
meillo@97
|
1469 .Ci ee4f43cf2ef0084ec698e4e87159a94c01940622
|
|
meillo@95
|
1470 This switch had introduced an awkward behavior, as explained in nmh's
|
|
meillo@95
|
1471 man page for
|
|
meillo@95
|
1472 .Mp comp (1):
|
|
meillo@98
|
1473 .QS
|
|
meillo@98
|
1474 The \-editor editor switch indicates the editor to use for
|
|
meillo@98
|
1475 the initial edit. Upon exiting from the editor, comp will
|
|
meillo@98
|
1476 invoke the whatnow program. See whatnow(1) for a discussion
|
|
meillo@98
|
1477 of available options. The invocation of this program can be
|
|
meillo@98
|
1478 inhibited by using the \-nowhatnowproc switch. (In truth of
|
|
meillo@98
|
1479 fact, it is the whatnow program which starts the initial
|
|
meillo@98
|
1480 edit. Hence, \-nowhatnowproc will prevent any edit from
|
|
meillo@95
|
1481 occurring.)
|
|
meillo@98
|
1482 .QE
|
|
meillo@95
|
1483 .P
|
|
meillo@95
|
1484 Effectively, the
|
|
meillo@95
|
1485 .Sw -nowhatnowproc
|
|
meillo@100
|
1486 switch creates only a draft message.
|
|
meillo@95
|
1487 As
|
|
meillo@95
|
1488 .Cl "-whatnowproc true
|
|
meillo@95
|
1489 causes the same behavior, the
|
|
meillo@95
|
1490 .Sw -nowhatnowproc
|
|
meillo@95
|
1491 switch was removed for being redundant.
|
|
meillo@100
|
1492 Likely, the
|
|
meillo@95
|
1493 .Sw -nowhatnowproc
|
|
meillo@100
|
1494 switch was intended to be used by front-ends.
|
|
meillo@95
|
1495
|
|
meillo@95
|
1496
|
|
meillo@95
|
1497 .U3 "Compatibility Switches
|
|
meillo@95
|
1498 .BU
|
|
meillo@95
|
1499 The hidden
|
|
meillo@95
|
1500 .Sw -[no]total
|
|
meillo@95
|
1501 switches of
|
|
meillo@95
|
1502 .Pn flist .
|
|
meillo@95
|
1503 They were simply the inverse of the visible
|
|
meillo@95
|
1504 .Sw -[no]fast
|
|
meillo@95
|
1505 switches:
|
|
meillo@95
|
1506 .Sw -total
|
|
meillo@95
|
1507 was
|
|
meillo@95
|
1508 .Sw -nofast
|
|
meillo@95
|
1509 and
|
|
meillo@95
|
1510 .Sw -nototal
|
|
meillo@95
|
1511 was
|
|
meillo@95
|
1512 .Sw -fast .
|
|
meillo@95
|
1513 I removed the
|
|
meillo@95
|
1514 .Sw -[no]total
|
|
meillo@95
|
1515 legacy.
|
|
meillo@97
|
1516 .Ci ea21fe2c4bd23c639bef251398fae809875732ec
|
|
meillo@95
|
1517 .BU
|
|
meillo@95
|
1518 The
|
|
meillo@95
|
1519 .Sw -subject
|
|
meillo@95
|
1520 switch of
|
|
meillo@95
|
1521 .Pn sortm
|
|
meillo@95
|
1522 existed for compatibility only.
|
|
meillo@95
|
1523 It can be fully replaced by
|
|
meillo@95
|
1524 .Cl "-textfield subject
|
|
meillo@95
|
1525 thus it was removed.
|
|
meillo@97
|
1526 .Ci 00140a3c86e9def69d98ba2ffd4d6e50ef6326ea
|
|
meillo@95
|
1527
|
|
meillo@95
|
1528
|
|
meillo@95
|
1529 .U3 "Various
|
|
meillo@95
|
1530 .BU
|
|
meillo@96
|
1531 In order to avoid prefix collisions among switch names, the
|
|
meillo@95
|
1532 .Sw -version
|
|
meillo@95
|
1533 switch was renamed to
|
|
meillo@95
|
1534 .Sw -Version
|
|
meillo@95
|
1535 (with capital `V').
|
|
meillo@97
|
1536 .Ci 32b2354dbaf4bf934936eb5b102a4a3d2fdd209a
|
|
meillo@95
|
1537 Every program has the
|
|
meillo@95
|
1538 .Sw -version
|
|
meillo@95
|
1539 switch but its first three letters collided with the
|
|
meillo@95
|
1540 .Sw -verbose
|
|
meillo@95
|
1541 switch, present in many programs.
|
|
meillo@95
|
1542 The rename solved this problem once for all.
|
|
meillo@95
|
1543 Although this rename breaks a basic interface, having the
|
|
meillo@95
|
1544 .Sw -V
|
|
meillo@95
|
1545 abbreviation to display the version information, isn't all too bad.
|
|
meillo@95
|
1546 .BU
|
|
meillo@95
|
1547 .Sw -[no]preserve
|
|
meillo@95
|
1548 of
|
|
meillo@95
|
1549 .Pn refile
|
|
meillo@95
|
1550 was removed because what use was it anyway?
|
|
meillo@98
|
1551 .QS
|
|
meillo@95
|
1552 Normally when a message is refiled, for each destination
|
|
meillo@95
|
1553 folder it is assigned the number which is one above the current
|
|
meillo@95
|
1554 highest message number in that folder. Use of the
|
|
meillo@95
|
1555 \-preserv [sic!] switch will override this message renaming, and try
|
|
meillo@95
|
1556 to preserve the number of the message. If a conflict for a
|
|
meillo@95
|
1557 particular folder occurs when using the \-preserve switch,
|
|
meillo@95
|
1558 then refile will use the next available message number which
|
|
meillo@95
|
1559 is above the message number you wish to preserve.
|
|
meillo@98
|
1560 .QE
|
|
meillo@95
|
1561 .BU
|
|
meillo@95
|
1562 The removal of the
|
|
meillo@95
|
1563 .Sw -[no]reverse
|
|
meillo@95
|
1564 switches of
|
|
meillo@95
|
1565 .Pn scan
|
|
meillo@97
|
1566 .Ci 8edc5aaf86f9f77124664f6801bc6c6cdf258173
|
|
meillo@95
|
1567 is a bug fix, supported by the comments
|
|
meillo@95
|
1568 ``\-[no]reverse under #ifdef BERK (I really HATE this)''
|
|
meillo@95
|
1569 by Rose and
|
|
meillo@95
|
1570 ``Lists messages in reverse order with the `\-reverse' switch.
|
|
meillo@95
|
1571 This should be considered a bug.'' by Romine in the documentation.
|
|
meillo@97
|
1572 The question remains why neither Rose and Romine had fixed this
|
|
meillo@95
|
1573 bug in the Eighties when they wrote these comments nor has anyone
|
|
meillo@95
|
1574 thereafter.
|
|
meillo@93
|
1575
|
|
meillo@93
|
1576
|
|
meillo@93
|
1577 .ig
|
|
meillo@93
|
1578
|
|
meillo@95
|
1579 forw: [no]dashstuffing(mhl)
|
|
meillo@93
|
1580
|
|
meillo@95
|
1581 mhshow: [no]pause [no]serialonly
|
|
meillo@93
|
1582
|
|
meillo@93
|
1583 mhmail: resent queued
|
|
meillo@93
|
1584 inc: snoop, (pop)
|
|
meillo@93
|
1585
|
|
meillo@95
|
1586 mhl: [no]faceproc folder sleep
|
|
meillo@95
|
1587 [no]dashstuffing(forw) digest list volume number issue number
|
|
meillo@93
|
1588
|
|
meillo@95
|
1589 prompter: [no]doteof
|
|
meillo@93
|
1590
|
|
meillo@93
|
1591 refile: [no]preserve [no]unlink [no]rmmproc
|
|
meillo@93
|
1592
|
|
meillo@95
|
1593 send: [no]forward [no]mime [no]msgid
|
|
meillo@93
|
1594 [no]push split [no]unique (sasl) width snoop [no]dashstuffing
|
|
meillo@93
|
1595 attach attachformat
|
|
meillo@93
|
1596 whatnow: (noedit) attach
|
|
meillo@93
|
1597
|
|
meillo@93
|
1598 slocal: [no]suppressdups
|
|
meillo@93
|
1599
|
|
meillo@95
|
1600 spost: [no]filter [no]backup width [no]push idanno
|
|
meillo@93
|
1601 [no]check(whom) whom(whom)
|
|
meillo@93
|
1602
|
|
meillo@93
|
1603 whom: ???
|
|
meillo@93
|
1604
|
|
meillo@95
|
1605 ..
|
|
meillo@93
|
1606
|
|
meillo@93
|
1607
|
|
meillo@93
|
1608 .ig
|
|
meillo@93
|
1609
|
|
meillo@93
|
1610 .P
|
|
meillo@93
|
1611 In the best case, all switches are unambiguous on the first character,
|
|
meillo@93
|
1612 or on the three-letter prefix for the `no' variants.
|
|
meillo@96
|
1613 Reducing switch prefix collisions, shortens the necessary prefix length
|
|
meillo@93
|
1614 the user must type.
|
|
meillo@93
|
1615 Having less switches helps best.
|
|
meillo@93
|
1616
|
|
meillo@93
|
1617 ..
|
|
meillo@58
|
1618
|
|
meillo@95
|
1619
|
|
meillo@102
|
1620 .\" XXX: whatnow prompt commands
|
|
meillo@102
|
1621
|
|
meillo@102
|
1622
|
|
meillo@95
|
1623
|
|
meillo@95
|
1624
|
|
meillo@74
|
1625 .H1 "Modernizing
|
|
meillo@102
|
1626 .P
|
|
meillo@102
|
1627 The code base of mmh originates from the late Seventies.
|
|
meillo@102
|
1628 Through the Eighties, extensive work had been done on it.
|
|
meillo@102
|
1629 In the Nineties, it had been partly reorganized and extended.
|
|
meillo@102
|
1630 Relicts from each decade have gathered in the code base.
|
|
meillo@102
|
1631 My goal was to modernize the code base.
|
|
meillo@102
|
1632
|
|
meillo@102
|
1633 .P
|
|
meillo@102
|
1634 FIXME functional aspect only here
|
|
meillo@102
|
1635 .P
|
|
meillo@102
|
1636 FIXME ref to `code style' for non-functional aspects.
|
|
meillo@58
|
1637
|
|
meillo@58
|
1638
|
|
meillo@100
|
1639 .H2 "Code Relicts
|
|
meillo@0
|
1640 .P
|
|
meillo@102
|
1641 My position to drop obsolete functionality of mmh to remove old code
|
|
meillo@102
|
1642 is much more revolutional than the nmh community likes it.
|
|
meillo@102
|
1643 Without the need to justify my decisions, I was able to quickly
|
|
meillo@20
|
1644 remove functionality I considered ancient.
|
|
meillo@20
|
1645 The need to discuss my decisions with
|
|
meillo@102
|
1646 peers likely would have slowed this process down.
|
|
meillo@102
|
1647 Of course, I researched if a particular feature really should be dropped.
|
|
meillo@102
|
1648 Having not had any
|
|
meillo@12
|
1649 contact to this feature within my computer life was a first indicator to
|
|
meillo@12
|
1650 drop it, but I also asked others and searched the literature for modern
|
|
meillo@102
|
1651 usage of the feature.
|
|
meillo@102
|
1652 If it appeared to be truly ancient, I dropped it.
|
|
meillo@12
|
1653 The reason for dropping is always part of the commit message in the
|
|
meillo@102
|
1654 version control system.
|
|
meillo@102
|
1655 Thus, it is easy for others to check their
|
|
meillo@12
|
1656 view on the topic with mine and possibly to argue for reinclusion.
|
|
meillo@12
|
1657
|
|
meillo@102
|
1658
|
|
meillo@101
|
1659 .U3 "MMDF maildrop support
|
|
meillo@12
|
1660 .P
|
|
meillo@102
|
1661 I did drop any support for the MMDF maildrop format.
|
|
meillo@102
|
1662 This type of format
|
|
meillo@12
|
1663 is conceptionally similar to the mbox format, but uses four bytes with
|
|
meillo@12
|
1664 value 1 (\fL^A^A^A^A\fP) as message delimiter,
|
|
meillo@18
|
1665 instead of the string ``\fLFrom\ \fP''.
|
|
meillo@12
|
1666 Due to the similarity and mbox being the de-facto standard maildrop
|
|
meillo@12
|
1667 format on Unix, but also due to the larger influence of Sendmail than MMDF,
|
|
meillo@12
|
1668 the MMDF maildrop format had vanished.
|
|
meillo@12
|
1669 .P
|
|
meillo@102
|
1670 The simplifications within the code were only moderate.
|
|
meillo@102
|
1671 Switches could be removed from tools like
|
|
meillo@12
|
1672 .L packf ,
|
|
meillo@102
|
1673 which generate packed mailboxes.
|
|
meillo@102
|
1674 Only one packed mailbox format remained: mbox.
|
|
meillo@12
|
1675 The most important changes affect the equally named mail parsing routine in
|
|
meillo@12
|
1676 .L sbr/m_getfld.c .
|
|
meillo@12
|
1677 The direct MMDF code had been removed, but as now only one packed mailbox
|
|
meillo@12
|
1678 format is left, code structure simplifications are likely possible.
|
|
meillo@12
|
1679 The reason why they are still outstanding is the heavily optimized code
|
|
meillo@18
|
1680 of
|
|
meillo@18
|
1681 .Fu m_getfld() .
|
|
meillo@18
|
1682 Changes beyond a small local scope \(en
|
|
meillo@12
|
1683 which restructuring in its core is \(en cause a high risk of damaging
|
|
meillo@102
|
1684 the intricate workings of the optimized code.
|
|
meillo@102
|
1685 This problem is know to the developers of nmh, too.
|
|
meillo@102
|
1686 They also avoid touching this minefield if possible.
|
|
meillo@12
|
1687
|
|
meillo@101
|
1688 .U3 "UUCP Bang Paths
|
|
meillo@12
|
1689 .P
|
|
meillo@12
|
1690 More questionably than the former topic is the removal of support for the
|
|
meillo@102
|
1691 UUCP bang path address style.
|
|
meillo@102
|
1692 However, the user may translate the bang
|
|
meillo@12
|
1693 paths on retrieval to Internet addresses and the other way on posting
|
|
meillo@102
|
1694 messages.
|
|
meillo@102
|
1695 The former can be done my an MDA like procmail; the latter
|
|
meillo@102
|
1696 by a sendmail wrapper.
|
|
meillo@102
|
1697 This would ensure that any address handling would work as expected.
|
|
meillo@102
|
1698 However, it might just work well without any
|
|
meillo@12
|
1699 such modifications, as mmh does not touch addresses much, in general.
|
|
meillo@12
|
1700 But I can't ensure as I have never used an environment with bang paths.
|
|
meillo@12
|
1701 Also, the behavior might break at any point in further development.
|
|
meillo@12
|
1702
|
|
meillo@101
|
1703 .U3 "Hardcopy terminal support
|
|
meillo@12
|
1704 .P
|
|
meillo@12
|
1705 More of a funny anecdote is the remaining of a check for printing to a
|
|
meillo@12
|
1706 hardcopy terminal until Spring 2012, when I finally removed it.
|
|
meillo@12
|
1707 I surely would be very happy to see such a terminal in action, maybe
|
|
meillo@12
|
1708 actually being able to work on it, but I fear my chances are null.
|
|
meillo@12
|
1709 .P
|
|
meillo@12
|
1710 The check only prevented a pager to be placed between the outputting
|
|
meillo@18
|
1711 program (\c
|
|
meillo@18
|
1712 .Pn mhl )
|
|
meillo@102
|
1713 and the terminal.
|
|
meillo@102
|
1714 This could have been ensured with the
|
|
meillo@82
|
1715 .Sw -nomoreproc
|
|
meillo@18
|
1716 at the command line statically, too.
|
|
meillo@12
|
1717
|
|
meillo@101
|
1718 .U3 "Removed support for header fields
|
|
meillo@12
|
1719 .P
|
|
meillo@84
|
1720 The
|
|
meillo@84
|
1721 .Hd Encrypted
|
|
meillo@84
|
1722 header field had been introduced by RFC\^822, but already
|
|
meillo@102
|
1723 marked legacy in RFC 2822.
|
|
meillo@102
|
1724 It was superseded by FIXME.
|
|
meillo@84
|
1725 Mmh does no more support this header field.
|
|
meillo@12
|
1726 .P
|
|
meillo@84
|
1727 Native support for
|
|
meillo@84
|
1728 .Hd Face
|
|
meillo@84
|
1729 header fields had been removed, as well.
|
|
meillo@84
|
1730 The feature is similar to the
|
|
meillo@84
|
1731 .Hd X-Face
|
|
meillo@84
|
1732 header field in its intent,
|
|
meillo@21
|
1733 but takes a different approach to store the image.
|
|
meillo@84
|
1734 Instead of encoding the image data directly into the header field,
|
|
meillo@84
|
1735 the it contains the hostname and UDP port where the image
|
|
meillo@21
|
1736 date could be retrieved.
|
|
meillo@84
|
1737 Neither
|
|
meillo@84
|
1738 .Hd X-Face
|
|
meillo@84
|
1739 nor the here described
|
|
meillo@84
|
1740 .Hd Face
|
|
meillo@84
|
1741 system
|
|
meillo@21
|
1742 \**
|
|
meillo@21
|
1743 .FS
|
|
meillo@21
|
1744 There is also a newer but different system, invented 2005,
|
|
meillo@84
|
1745 using
|
|
meillo@84
|
1746 .Hd Face
|
|
meillo@84
|
1747 headers.
|
|
meillo@84
|
1748 It is the successor of
|
|
meillo@84
|
1749 .Hd X-Face
|
|
meillo@84
|
1750 providing colored PNG images.
|
|
meillo@21
|
1751 .FE
|
|
meillo@21
|
1752 became well used in the large scale.
|
|
meillo@21
|
1753 It's still possible to use a Face systems,
|
|
meillo@21
|
1754 although mmh does not provide support for any of the different systems
|
|
meillo@21
|
1755 anymore. It's fairly easy to write a small shell script to
|
|
meillo@21
|
1756 extract the embedded or fetch the external Face data and display the image.
|
|
meillo@84
|
1757 Own
|
|
meillo@84
|
1758 .Hd Face
|
|
meillo@84
|
1759 header field can be added into the draft template files.
|
|
meillo@21
|
1760 .P
|
|
meillo@84
|
1761 .Hd Content-MD5
|
|
meillo@84
|
1762 header fields were introduced by RFC\^1864. They provide only
|
|
meillo@12
|
1763 a verification of data corruption during the transfer. By no means can
|
|
meillo@12
|
1764 they ensure verbatim end-to-end delivery of the contents. This is clearly
|
|
meillo@12
|
1765 stated in the RFC. The proper approach to provide verificationability
|
|
meillo@12
|
1766 of content in an end-to-end relationship is the use of digital cryptography
|
|
meillo@12
|
1767 (RFCs FIXME). On the other hand, transfer protocols should ensure the
|
|
meillo@12
|
1768 integrity of the transmission. In combinations these two approaches
|
|
meillo@84
|
1769 make the
|
|
meillo@84
|
1770 .Hd Content-MD5
|
|
meillo@84
|
1771 header field useless. In consequence, I removed
|
|
meillo@12
|
1772 the support for it. By this removal, MD5 computation is not needed
|
|
meillo@12
|
1773 anywhere in mmh. Hence, over 500 lines of code were removed by this one
|
|
meillo@84
|
1774 change. Even if the
|
|
meillo@84
|
1775 .Hd Content-MD5
|
|
meillo@84
|
1776 header field is useful sometimes,
|
|
meillo@89
|
1777 I value its usefulness less than the improvement in maintainability, caused
|
|
meillo@12
|
1778 by the removal.
|
|
meillo@12
|
1779
|
|
meillo@101
|
1780 .U3 "Prompter's Control Keys
|
|
meillo@20
|
1781 .P
|
|
meillo@20
|
1782 The program
|
|
meillo@20
|
1783 .Pn prompter
|
|
meillo@20
|
1784 queries the user to fill in a message form. When used by
|
|
meillo@20
|
1785 .Pn comp
|
|
meillo@20
|
1786 as:
|
|
meillo@82
|
1787 .VS
|
|
meillo@82
|
1788 comp -editor prompter
|
|
meillo@82
|
1789 VE
|
|
meillo@20
|
1790 the resulting behavior is similar to
|
|
meillo@20
|
1791 .Pn mailx .
|
|
meillo@51
|
1792 Apparently,
|
|
meillo@20
|
1793 .Pn prompter
|
|
meillo@20
|
1794 hadn't been touched lately. Otherwise it's hardly explainable why it
|
|
meillo@20
|
1795 still offered the switches
|
|
meillo@84
|
1796 .Sw -erase
|
|
meillo@84
|
1797 .Ar chr
|
|
meillo@20
|
1798 and
|
|
meillo@84
|
1799 .Sw -kill
|
|
meillo@84
|
1800 .Ar chr
|
|
meillo@20
|
1801 to name the characters for command line editing.
|
|
meillo@21
|
1802 The times when this had been necessary are long time gone.
|
|
meillo@20
|
1803 Today these things work out-of-the-box, and if not, are configured
|
|
meillo@20
|
1804 with the standard tool
|
|
meillo@20
|
1805 .Pn stty .
|
|
meillo@20
|
1806
|
|
meillo@101
|
1807 .U3 "Vfork and Retry Loops
|
|
meillo@21
|
1808 .P
|
|
meillo@51
|
1809 MH creates many processes, which is a consequence of the tool chest approach.
|
|
meillo@21
|
1810 In earlier times
|
|
meillo@21
|
1811 .Fu fork()
|
|
meillo@21
|
1812 had been an expensive system call, as the process's whole image needed
|
|
meillo@21
|
1813 to be duplicated. One common case is replacing the image with
|
|
meillo@21
|
1814 .Fu exec()
|
|
meillo@21
|
1815 right after having forked the child process.
|
|
meillo@21
|
1816 To speed up this case, the
|
|
meillo@21
|
1817 .Fu vfork()
|
|
meillo@21
|
1818 system call was invented at Berkeley. It completely omits copying the
|
|
meillo@21
|
1819 image. If the image gets replaced right afterwards then unnecessary
|
|
meillo@21
|
1820 work is omited. On old systems this results in large speed ups.
|
|
meillo@21
|
1821 MH uses
|
|
meillo@21
|
1822 .Fu vfork()
|
|
meillo@21
|
1823 whenever possible.
|
|
meillo@21
|
1824 .P
|
|
meillo@21
|
1825 Memory management units that support copy-on-write semantics make
|
|
meillo@21
|
1826 .Fu fork()
|
|
meillo@21
|
1827 almost as fast as
|
|
meillo@21
|
1828 .Fu vfork()
|
|
meillo@21
|
1829 in the cases when they can be exchanged.
|
|
meillo@21
|
1830 With
|
|
meillo@21
|
1831 .Fu vfork()
|
|
meillo@51
|
1832 being more error-prone and hardly faster, it's preferable to simply
|
|
meillo@21
|
1833 use
|
|
meillo@21
|
1834 .Fu fork()
|
|
meillo@21
|
1835 instead.
|
|
meillo@21
|
1836 .P
|
|
meillo@21
|
1837 Related to the costs of
|
|
meillo@21
|
1838 .Fu fork()
|
|
meillo@21
|
1839 is the probability of its success.
|
|
meillo@21
|
1840 Today on modern systems, the system call will succeed almost always.
|
|
meillo@51
|
1841 In the Eighties on heavy loaded systems, as they were common at
|
|
meillo@21
|
1842 universities, this had been different. Thus, many of the
|
|
meillo@21
|
1843 .Fu fork()
|
|
meillo@21
|
1844 calls were wrapped into loops to retry to fork several times in
|
|
meillo@21
|
1845 short intervals, in case of previous failure.
|
|
meillo@21
|
1846 In mmh, the program aborts at once if the fork failed.
|
|
meillo@21
|
1847 The user can reexecute the command then. This is expected to be a
|
|
meillo@21
|
1848 very rare case on modern systems, especially personal ones, which are
|
|
meillo@21
|
1849 common today.
|
|
meillo@21
|
1850
|
|
meillo@12
|
1851
|
|
meillo@58
|
1852 .H2 "Attachments
|
|
meillo@22
|
1853 .P
|
|
meillo@101
|
1854 The mind model of email attachments is unrelated to MIME.
|
|
meillo@101
|
1855 Although the MIME RFCs (2045 through 2049) define the technical
|
|
meillo@101
|
1856 requirements for having attachments, they do not mention the the word
|
|
meillo@101
|
1857 ``attachment''.
|
|
meillo@101
|
1858 Instead of attachments, MIME talks about ``multi-part message bodies''
|
|
meillo@101
|
1859 [RFC\|2045], a more general concept.
|
|
meillo@101
|
1860 Multi-part messages are messages
|
|
meillo@101
|
1861 ``in which one or more different
|
|
meillo@101
|
1862 sets of data are combined in a single body''
|
|
meillo@101
|
1863 [RFC\|2046].
|
|
meillo@101
|
1864 MIME keeps its descriptions generic;
|
|
meillo@101
|
1865 it does not imply specific usage models.
|
|
meillo@101
|
1866 In email one usage model became prevalent: attachments.
|
|
meillo@101
|
1867 The idea is having a main text document with files of arbitrary kind
|
|
meillo@101
|
1868 attached to it.
|
|
meillo@101
|
1869 In MIME terms, this is a multi-part message having a text part first
|
|
meillo@101
|
1870 and parts of arbitray type following.
|
|
meillo@101
|
1871 .P
|
|
meillo@101
|
1872 MH's MIME support is a direct implementation of the RFCs.
|
|
meillo@101
|
1873 The perception of the topic described in the RFCs is clearly visible
|
|
meillo@101
|
1874 in MH's implementation.
|
|
meillo@101
|
1875 Thus, MH had all the MIME features but no idea of attachments.
|
|
meillo@101
|
1876 Today, however, users don't need all the MIME features but they want
|
|
meillo@101
|
1877 convenient attachment handling.
|
|
meillo@102
|
1878
|
|
meillo@102
|
1879 .U3 "Composing MIME Messages
|
|
meillo@102
|
1880 .P
|
|
meillo@102
|
1881 In order to improve the situation on the message composing side,
|
|
meillo@102
|
1882 Jon Steinhart had added an attachment system to nmh in 2002.
|
|
meillo@101
|
1883 .Ci 7480dbc14bc90f2d872d434205c0784704213252
|
|
meillo@102
|
1884 In the file
|
|
meillo@102
|
1885 .Fn docs/README-ATTACHMENTS ,
|
|
meillo@102
|
1886 he described his motivation to do so as such:
|
|
meillo@101
|
1887 .QS
|
|
meillo@101
|
1888 Although nmh contains the necessary functionality for MIME message handing,
|
|
meillo@101
|
1889 the interface to this functionality is pretty obtuse.
|
|
meillo@101
|
1890 There's no way that I'm ever going to convince my partner to write
|
|
meillo@101
|
1891 .Pn mhbuild
|
|
meillo@101
|
1892 composition files!
|
|
meillo@101
|
1893 .QE
|
|
meillo@102
|
1894 .LP
|
|
meillo@102
|
1895 With this change, the mind model of attachments entered nmh.
|
|
meillo@102
|
1896 In the same document:
|
|
meillo@101
|
1897 .QS
|
|
meillo@101
|
1898 These changes simplify the task of managing attachments on draft files.
|
|
meillo@101
|
1899 They allow attachments to be added, listed, and deleted.
|
|
meillo@101
|
1900 MIME messages are automatically created when drafts with attachments
|
|
meillo@101
|
1901 are sent.
|
|
meillo@101
|
1902 .QE
|
|
meillo@102
|
1903 .LP
|
|
meillo@102
|
1904 Unfortunately, the attachment system,
|
|
meillo@102
|
1905 like any new facilities in nmh,
|
|
meillo@102
|
1906 was deactive by default.
|
|
meillo@101
|
1907 .P
|
|
meillo@101
|
1908 During my work in Argentina, I tried to improve the attachment system.
|
|
meillo@102
|
1909 But, because of great opposition in the nmh community,
|
|
meillo@102
|
1910 my patch died as a proposal on the mailing list, after long discussions.
|
|
meillo@101
|
1911 .[
|
|
meillo@101
|
1912 nmh-workers attachment proposal
|
|
meillo@101
|
1913 .]
|
|
meillo@102
|
1914 In Januar 2012, I extended the patch and applied it to mmh.
|
|
meillo@101
|
1915 .Ci 8ff284ff9167eff8f5349481529332d59ed913b1
|
|
meillo@102
|
1916 In mmh, the attachment system is active by default.
|
|
meillo@102
|
1917 Instead of command line switches, the
|
|
meillo@102
|
1918 .Pe Attachment-Header
|
|
meillo@102
|
1919 profile entry is used to specify
|
|
meillo@102
|
1920 the name of the attachment header field.
|
|
meillo@102
|
1921 It is pre-defined to
|
|
meillo@102
|
1922 .Hd Attach .
|
|
meillo@101
|
1923 .P
|
|
meillo@101
|
1924 To add an attachment to a draft, simply add an attachment header:
|
|
meillo@101
|
1925 .VS
|
|
meillo@101
|
1926 To: bob
|
|
meillo@101
|
1927 Subject: The file you wanted
|
|
meillo@101
|
1928 Attach: /path/to/the/file-bob-wanted
|
|
meillo@101
|
1929 --------
|
|
meillo@101
|
1930 Here it is.
|
|
meillo@101
|
1931 VE
|
|
meillo@101
|
1932 The header field can be added to the draft manually in the editor,
|
|
meillo@102
|
1933 or by using the `attach' command at the WhatNow prompt, or
|
|
meillo@102
|
1934 non-interactively with
|
|
meillo@101
|
1935 .Pn anno :
|
|
meillo@101
|
1936 .VS
|
|
meillo@102
|
1937 anno -append -nodate -component Attach -text /path/to/attachment
|
|
meillo@101
|
1938 VE
|
|
meillo@102
|
1939 Drafts with attachment headers are converted to MIME automatically by
|
|
meillo@102
|
1940 .Pn send .
|
|
meillo@102
|
1941 The conversion to MIME is invisible to the user.
|
|
meillo@102
|
1942 The draft stored in the draft folder is always in source form, with
|
|
meillo@101
|
1943 attachment headers.
|
|
meillo@101
|
1944 If the MIMEification fails, for instance because the file to attach
|
|
meillo@101
|
1945 is not accessible, the original draft is not changed.
|
|
meillo@101
|
1946 .P
|
|
meillo@102
|
1947 The attachment system handles the forwarding of messages, too.
|
|
meillo@101
|
1948 If the attachment header value starts with a plus character (`+'),
|
|
meillo@101
|
1949 like in
|
|
meillo@101
|
1950 .Cl "Attach: +bob 30 42" ,
|
|
meillo@101
|
1951 The given messages in the specified folder will be attached.
|
|
meillo@101
|
1952 This allowed to simplify
|
|
meillo@101
|
1953 .Pn forw .
|
|
meillo@101
|
1954 .Ci f41f04cf4ceca7355232cf7413e59afafccc9550
|
|
meillo@101
|
1955 .P
|
|
meillo@101
|
1956 Closely related to attachments is non-ASCII text content,
|
|
meillo@101
|
1957 because it requires MIME too.
|
|
meillo@102
|
1958 In nmh, the user needed to call `mime' at the WhatNow prompt
|
|
meillo@101
|
1959 to have the draft converted to MIME.
|
|
meillo@102
|
1960 This was necessary whenever the draft contained non-ASCII characters.
|
|
meillo@101
|
1961 If the user did not call `mime', a broken message would be sent.
|
|
meillo@101
|
1962 Therefore, the
|
|
meillo@101
|
1963 .Pe automimeproc
|
|
meillo@101
|
1964 profile entry could be specified to have the `mime' command invoked
|
|
meillo@102
|
1965 automatically each time.
|
|
meillo@101
|
1966 Unfortunately, this approach conflicted with with attachment system
|
|
meillo@101
|
1967 because the draft would already be in MIME format at the time
|
|
meillo@101
|
1968 when the attachment system wanted to MIMEify it.
|
|
meillo@102
|
1969 To use nmh's attachment system, `mime' must not be called at the
|
|
meillo@102
|
1970 WhatNow prompt and
|
|
meillo@101
|
1971 .Pe automimeproc
|
|
meillo@102
|
1972 must not be set in the profile.
|
|
meillo@101
|
1973 But then the case of non-ASCII text without attachment headers was
|
|
meillo@101
|
1974 not caught.
|
|
meillo@102
|
1975 All in all, the solution was complex and irritating.
|
|
meillo@102
|
1976 My patch from December 2010 would have simplified the situation.
|
|
meillo@102
|
1977 .P
|
|
meillo@101
|
1978 Mmh's current solution is even more elaborate.
|
|
meillo@101
|
1979 Any necessary MIMEification is done automatically.
|
|
meillo@101
|
1980 There is no `mime' command at the WhatNow prompt anymore.
|
|
meillo@102
|
1981 The draft will be converted automatically to MIME when either an
|
|
meillo@102
|
1982 attachment header or non-ASCII text is present.
|
|
meillo@101
|
1983 Further more, the special meaning of the hash character (`#')
|
|
meillo@102
|
1984 at line beginnings in the draft message is removed.
|
|
meillo@102
|
1985 Users need not at all deal with the whole topic.
|
|
meillo@101
|
1986 .P
|
|
meillo@102
|
1987 Although the new approach does not anymore support arbitrary MIME
|
|
meillo@102
|
1988 compositions directly, the full power of
|
|
meillo@101
|
1989 .Pn mhbuild
|
|
meillo@101
|
1990 can still be accessed.
|
|
meillo@102
|
1991 Given no attachment headers are included, the user can create
|
|
meillo@101
|
1992 .Pn mhbuild
|
|
meillo@102
|
1993 composition drafts like in nmh.
|
|
meillo@101
|
1994 Then, at the WhatNow prompt, he needs to invoke
|
|
meillo@101
|
1995 .Cl "edit mhbuild
|
|
meillo@101
|
1996 to convert it to MIME.
|
|
meillo@102
|
1997 Because the resulting draft does neither contain non-aASCII characters
|
|
meillo@102
|
1998 nor has it attachment headers, the attachment system will not touch it.
|
|
meillo@101
|
1999 .P
|
|
meillo@101
|
2000 The approach taken in mmh is taylored towards todays most common case:
|
|
meillo@101
|
2001 a text part with possibly attachments.
|
|
meillo@102
|
2002 This case is simplified a lot for users.
|
|
meillo@102
|
2003
|
|
meillo@102
|
2004 .U3 "MIME Type Guessing
|
|
meillo@102
|
2005 .P
|
|
meillo@102
|
2006 The use of
|
|
meillo@101
|
2007 .Pn mhbuild
|
|
meillo@102
|
2008 composition drafts had one notable advantage over attachment headers
|
|
meillo@102
|
2009 from the programmer's point of view: The user provides the appropriate
|
|
meillo@102
|
2010 MIME types for files to include.
|
|
meillo@102
|
2011 The attachment system needs to find out the correct MIME type itself.
|
|
meillo@102
|
2012 This is a difficult task, yet it spares the user irritating work.
|
|
meillo@102
|
2013 Determining the correct MIME type of content is partly mechanical,
|
|
meillo@102
|
2014 partly intelligent work.
|
|
meillo@102
|
2015 Forcing the user to find out the correct MIME type,
|
|
meillo@102
|
2016 forces him to do partly mechanical work.
|
|
meillo@102
|
2017 Letting the computer do the work, can lead to bad choices for difficult
|
|
meillo@102
|
2018 content.
|
|
meillo@102
|
2019 For mmh, the latter option was chosen.
|
|
meillo@102
|
2020 .P
|
|
meillo@102
|
2021 Determining the MIME type by the suffix of the file name is a dumb
|
|
meillo@102
|
2022 approach, yet it is simple to implement and provides good results
|
|
meillo@102
|
2023 for the common cases.
|
|
meillo@102
|
2024 Mmh implements this approach in the
|
|
meillo@102
|
2025 .Pn print-mimetype
|
|
meillo@102
|
2026 script.
|
|
meillo@102
|
2027 Using it is the default choice.
|
|
meillo@102
|
2028 .P
|
|
meillo@102
|
2029 A far better but less portable approach is the use of
|
|
meillo@102
|
2030 .Pn file .
|
|
meillo@102
|
2031 This standard tool tries to determine the type of files.
|
|
meillo@102
|
2032 Unfortunately, its capabilities and accuracy varies from system to system.
|
|
meillo@102
|
2033 Additionally, its output was only intended for human beings,
|
|
meillo@102
|
2034 but not to be used by programs.
|
|
meillo@102
|
2035 It varies much.
|
|
meillo@102
|
2036 Nevertheless, modern versions of GNU
|
|
meillo@102
|
2037 .Pn file ,
|
|
meillo@102
|
2038 which is prevalent on the popular GNU/Linux systems,
|
|
meillo@102
|
2039 provides MIME type output in machine-readable form.
|
|
meillo@102
|
2040 Although this solution is highly system-dependent,
|
|
meillo@102
|
2041 it solves the difficult problem well.
|
|
meillo@102
|
2042 On systems where GNU
|
|
meillo@102
|
2043 .Pn file ,
|
|
meillo@102
|
2044 version 5.04 or higher, is available it should be used.
|
|
meillo@102
|
2045 One needs to specify the following profile entry to do so:
|
|
meillo@102
|
2046 .VS
|
|
meillo@102
|
2047 Mime-Type-Query: file -b --mime
|
|
meillo@102
|
2048 VE
|
|
meillo@102
|
2049 .LP
|
|
meillo@102
|
2050 Other versions of
|
|
meillo@102
|
2051 .Pn file
|
|
meillo@102
|
2052 might possibly be usable with wrapper scripts to reformat the output.
|
|
meillo@102
|
2053 The diversity among
|
|
meillo@102
|
2054 .Pn file
|
|
meillo@102
|
2055 implementations is great; one needs to check the local variant.
|
|
meillo@102
|
2056 .P
|
|
meillo@102
|
2057 If no MIME type can be determined, text content gets sent as
|
|
meillo@102
|
2058 `text/plain' and anything else under the generic fall-back type
|
|
meillo@102
|
2059 `application/octet-stream'.
|
|
meillo@102
|
2060 It is not possible in mmh to override the automatic MIME type guessing
|
|
meillo@102
|
2061 for a specific file.
|
|
meillo@102
|
2062 To do so, the user would need to know in advance for which file
|
|
meillo@102
|
2063 the automatic guessing does fail, or the system would require interaction.
|
|
meillo@102
|
2064 I consider both cases impractical.
|
|
meillo@102
|
2065 The existing solution should be sufficient.
|
|
meillo@102
|
2066 If not, the user may always fall back to
|
|
meillo@102
|
2067 .Pn mhbuild
|
|
meillo@102
|
2068 composition drafts and ignore the attachment system.
|
|
meillo@101
|
2069
|
|
meillo@102
|
2070
|
|
meillo@102
|
2071 .U3 "Storing Attachments
|
|
meillo@102
|
2072 .P
|
|
meillo@102
|
2073 FIXME
|
|
meillo@102
|
2074
|
|
meillo@102
|
2075
|
|
meillo@102
|
2076 .U3 "Showing MIME Messages
|
|
meillo@102
|
2077 .P
|
|
meillo@102
|
2078 FIXME
|
|
meillo@102
|
2079
|
|
meillo@58
|
2080
|
|
meillo@58
|
2081
|
|
meillo@58
|
2082 .H2 "Digital Cryptography
|
|
meillo@22
|
2083 .P
|
|
meillo@58
|
2084 Signing and encryption.
|
|
meillo@58
|
2085
|
|
meillo@58
|
2086
|
|
meillo@102
|
2087
|
|
meillo@102
|
2088 .H2 "Modern Defaults
|
|
meillo@22
|
2089 .P
|
|
meillo@102
|
2090 Just to give one example, for me it took one year of using nmh
|
|
meillo@102
|
2091 before I became aware of the existence of the attachment system.
|
|
meillo@102
|
2092 One could argue that this fact disqualifies my reading of the
|
|
meillo@102
|
2093 documentation.
|
|
meillo@102
|
2094 If I would have installed nmh from source back then, I could agree.
|
|
meillo@102
|
2095 Yet I had used a prepackaged version and had expected that it would
|
|
meillo@102
|
2096 just work.
|
|
meillo@58
|
2097
|
|
meillo@58
|
2098
|
|
meillo@58
|
2099
|
|
meillo@100
|
2100 .H1 "Code Style
|
|
meillo@22
|
2101 .P
|
|
meillo@58
|
2102 foo
|
|
meillo@58
|
2103
|
|
meillo@58
|
2104
|
|
meillo@58
|
2105 .H2 "Standard Code
|
|
meillo@22
|
2106 .P
|
|
meillo@58
|
2107 POSIX
|
|
meillo@22
|
2108
|
|
meillo@102
|
2109 .U3 "Converting to Standard Code
|
|
meillo@102
|
2110 .P
|
|
meillo@102
|
2111 One part of this task was converting obsolete code constructs
|
|
meillo@102
|
2112 to standard constructs.
|
|
meillo@102
|
2113 As I'm not even thirty years old and have no more than seven years of
|
|
meillo@102
|
2114 Unix experience, I needed to learn about the history in retrospective.
|
|
meillo@102
|
2115 Older people likely have used those ancient constructs themselves
|
|
meillo@102
|
2116 and have suffered from their incompatibilities and have longed for
|
|
meillo@102
|
2117 standardization.
|
|
meillo@102
|
2118 Unfortunately, I have only read that others had done so.
|
|
meillo@102
|
2119 This put me in a much more difficult positions when working on the old
|
|
meillo@102
|
2120 code.
|
|
meillo@102
|
2121 I needed to recherche what other would have known by heart from
|
|
meillo@102
|
2122 experience.
|
|
meillo@102
|
2123 All my programming experience comes from a time past ANSI C
|
|
meillo@102
|
2124 and past POSIX.
|
|
meillo@102
|
2125 Although I knew about the times before, I took the
|
|
meillo@102
|
2126 current state implicitly for granted most of the time.
|
|
meillo@102
|
2127 .P
|
|
meillo@102
|
2128 Being aware of
|
|
meillo@102
|
2129 these facts, I rather let people with more historic experience solve the
|
|
meillo@102
|
2130 task of converting the ancient code constructs to standardized ones.
|
|
meillo@102
|
2131 Luckily, Lyndon Nerenberg focused on this task at the nmh project.
|
|
meillo@102
|
2132 He converted large parts of the code to POSIX constructs, removing
|
|
meillo@102
|
2133 the conditionals compilation for now standardized features.
|
|
meillo@102
|
2134 I'm thankful for this task being solved. I only pulled the changes into
|
|
meillo@102
|
2135 mmh.
|
|
meillo@102
|
2136
|
|
meillo@102
|
2137
|
|
meillo@102
|
2138
|
|
meillo@22
|
2139
|
|
meillo@58
|
2140 .H2 "Separation
|
|
meillo@14
|
2141
|
|
meillo@58
|
2142 .U2 "MH Directory Split
|
|
meillo@0
|
2143 .P
|
|
meillo@19
|
2144 In MH and nmh, a personal setup had consisted of two parts:
|
|
meillo@19
|
2145 The MH profile, named
|
|
meillo@19
|
2146 .Fn \&.mh_profile
|
|
meillo@19
|
2147 and being located directly in the user's home directory.
|
|
meillo@19
|
2148 And the MH directory, where all his mail messages and also his personal
|
|
meillo@19
|
2149 forms, scan formats, other configuration files are stored. The location
|
|
meillo@19
|
2150 of this directory could be user-chosen. The default was to name it
|
|
meillo@19
|
2151 .Fn Mail
|
|
meillo@19
|
2152 and have it directly in the home directory.
|
|
meillo@19
|
2153 .P
|
|
meillo@19
|
2154 I've never liked the data storage and the configuration to be intermixed.
|
|
meillo@19
|
2155 They are different kinds of data. One part, are the messages,
|
|
meillo@19
|
2156 which are the data to operate on. The other part, are the personal
|
|
meillo@19
|
2157 configuration files, which are able to change the behavior of the operations.
|
|
meillo@19
|
2158 The actual operations are defined in the profile, however.
|
|
meillo@19
|
2159 .P
|
|
meillo@19
|
2160 When storing data, one should try to group data by its type.
|
|
meillo@19
|
2161 There's sense in the Unix file system hierarchy, where configuration
|
|
meillo@19
|
2162 file are stored separate (\c
|
|
meillo@19
|
2163 .Fn /etc )
|
|
meillo@19
|
2164 to the programs (\c
|
|
meillo@19
|
2165 .Fn /bin
|
|
meillo@19
|
2166 and
|
|
meillo@19
|
2167 .Fn /usr/bin )
|
|
meillo@19
|
2168 to their sources (\c
|
|
meillo@19
|
2169 .Fn /usr/src ).
|
|
meillo@19
|
2170 Such separation eases the backup management, for instance.
|
|
meillo@19
|
2171 .P
|
|
meillo@19
|
2172 In mmh, I've reorganized the file locations.
|
|
meillo@19
|
2173 Still there are two places:
|
|
meillo@19
|
2174 There's the mail storage directory, which, like in MH, contains all the
|
|
meillo@19
|
2175 messages, but, unlike in MH, nothing else.
|
|
meillo@19
|
2176 Its location still is user-chosen, with the default name
|
|
meillo@19
|
2177 .Fn Mail ,
|
|
meillo@19
|
2178 in the user's home directory. This is much similar to the case in nmh.
|
|
meillo@19
|
2179 The configuration files, however, are grouped together in the new directory
|
|
meillo@19
|
2180 .Fn \&.mmh
|
|
meillo@19
|
2181 in the user's home directory.
|
|
meillo@19
|
2182 The user's profile now is a file, named
|
|
meillo@19
|
2183 .Fn profile ,
|
|
meillo@19
|
2184 in this mmh directory.
|
|
meillo@19
|
2185 Consistently, the context file and all the personal forms, scan formats,
|
|
meillo@19
|
2186 and the like, are also there.
|
|
meillo@19
|
2187 .P
|
|
meillo@19
|
2188 The naming changed with the relocation.
|
|
meillo@19
|
2189 The directory where everything, except the profile, had been stored (\c
|
|
meillo@19
|
2190 .Fn $HOME/Mail ),
|
|
meillo@19
|
2191 used to be called \fIMH directory\fP. Now, this directory is called the
|
|
meillo@19
|
2192 user's \fImail storage\fP. The name \fImmh directory\fP is now given to
|
|
meillo@19
|
2193 the new directory
|
|
meillo@19
|
2194 (\c
|
|
meillo@19
|
2195 .Fn $HOME/.mmh ),
|
|
meillo@19
|
2196 containing all the personal configuration files.
|
|
meillo@19
|
2197 .P
|
|
meillo@19
|
2198 The separation of the files by type of content is logical and convenient.
|
|
meillo@19
|
2199 There are no functional differences as any possible setup known to me
|
|
meillo@19
|
2200 can be implemented with both approaches, although likely a bit easier
|
|
meillo@19
|
2201 with the new approach. The main goal of the change had been to provide
|
|
meillo@19
|
2202 sensible storage locations for any type of personal mmh file.
|
|
meillo@19
|
2203 .P
|
|
meillo@19
|
2204 In order for one user to have multiple MH setups, he can use the
|
|
meillo@19
|
2205 environment variable
|
|
meillo@19
|
2206 .Ev MH
|
|
meillo@19
|
2207 the point to a different profile file.
|
|
meillo@19
|
2208 The MH directory (mail storage plus personal configuration files) is
|
|
meillo@19
|
2209 defined by the
|
|
meillo@19
|
2210 .Pe Path
|
|
meillo@19
|
2211 profile entry.
|
|
meillo@19
|
2212 The context file could be defined by the
|
|
meillo@19
|
2213 .Pe context
|
|
meillo@19
|
2214 profile entry or by the
|
|
meillo@19
|
2215 .Ev MHCONTEXT
|
|
meillo@19
|
2216 environment variable.
|
|
meillo@19
|
2217 The latter is useful to have a distinct context (e.g. current folders)
|
|
meillo@19
|
2218 in each terminal window, for instance.
|
|
meillo@19
|
2219 In mmh, there are three environment variables now.
|
|
meillo@19
|
2220 .Ev MMH
|
|
meillo@19
|
2221 may be used to change the location of the mmh directory.
|
|
meillo@19
|
2222 .Ev MMHP
|
|
meillo@19
|
2223 and
|
|
meillo@19
|
2224 .Ev MMHC
|
|
meillo@19
|
2225 change the profile and context files, respectively.
|
|
meillo@19
|
2226 Besides providing a more consistent feel (which simply is the result
|
|
meillo@19
|
2227 of being designed anew), the set of personal configuration files can
|
|
meillo@19
|
2228 be chosen independently from the profile (including mail storage location)
|
|
meillo@19
|
2229 and context, now. Being it relevant for practical use or not, it
|
|
meillo@19
|
2230 de-facto is an improvement. However, the main achievement is the
|
|
meillo@19
|
2231 split between mail storage and personal configuration files.
|
|
meillo@17
|
2232
|
|
meillo@0
|
2233
|
|
meillo@58
|
2234 .H2 "Modularization
|
|
meillo@0
|
2235 .P
|
|
meillo@58
|
2236 whatnowproc
|
|
meillo@0
|
2237 .P
|
|
meillo@49
|
2238 The \fIMH library\fP
|
|
meillo@49
|
2239 .Fn libmh.a
|
|
meillo@49
|
2240 collects a bunch of standard functions that many of the MH tools need,
|
|
meillo@49
|
2241 like reading the profile or context files.
|
|
meillo@49
|
2242 This doesn't hurt the separation.
|
|
meillo@49
|
2243
|
|
meillo@58
|
2244
|
|
meillo@58
|
2245 .H2 "Style
|
|
meillo@58
|
2246 .P
|
|
meillo@58
|
2247 Code layout, goto, ...
|
|
meillo@58
|
2248
|
|
meillo@102
|
2249 .P
|
|
meillo@102
|
2250 anno rework
|
|
meillo@102
|
2251
|
|
meillo@58
|
2252
|
|
meillo@58
|
2253
|
|
meillo@58
|
2254
|
|
meillo@89
|
2255 .H1 "Concept Exploitation/Homogeneity
|
|
meillo@58
|
2256
|
|
meillo@58
|
2257
|
|
meillo@58
|
2258 .H2 "Draft Folder
|
|
meillo@58
|
2259 .P
|
|
meillo@58
|
2260 Historically, MH provided exactly one draft message, named
|
|
meillo@58
|
2261 .Fn draft
|
|
meillo@58
|
2262 and
|
|
meillo@58
|
2263 being located in the MH directory. When starting to compose another message
|
|
meillo@58
|
2264 before the former one was sent, the user had been questioned whether to use,
|
|
meillo@58
|
2265 refile or replace the old draft. Working on multiple drafts at the same time
|
|
meillo@58
|
2266 was impossible. One could only work on them in alteration by refiling the
|
|
meillo@58
|
2267 previous one to some directory and fetching some other one for reediting.
|
|
meillo@58
|
2268 This manual draft management needed to be done each time the user wanted
|
|
meillo@58
|
2269 to switch between editing one draft to editing another.
|
|
meillo@58
|
2270 .P
|
|
meillo@58
|
2271 To allow true parallel editing of drafts, in a straight forward way, the
|
|
meillo@58
|
2272 draft folder facility exists. It had been introduced already in July 1984
|
|
meillo@58
|
2273 by Marshall T. Rose. The facility was deactivated by default.
|
|
meillo@58
|
2274 Even in nmh, the draft folder facility remained deactivated by default.
|
|
meillo@58
|
2275 At least, Richard Coleman added the man page
|
|
meillo@58
|
2276 .Mp mh-draft(5)
|
|
meillo@58
|
2277 to document
|
|
meillo@58
|
2278 the feature well.
|
|
meillo@58
|
2279 .P
|
|
meillo@58
|
2280 The only advantage of not using the draft folder facility is the static
|
|
meillo@89
|
2281 name of the draft file. This could be an issue for MH front-ends like mh-e.
|
|
meillo@58
|
2282 But as they likely want to provide working on multiple drafts in parallel,
|
|
meillo@58
|
2283 the issue is only concerning compatibility. The aim of nmh to stay compatible
|
|
meillo@58
|
2284 prevented the default activation of the draft folder facility.
|
|
meillo@58
|
2285 .P
|
|
meillo@58
|
2286 On the other hand, a draft folder is the much more natural concept than
|
|
meillo@58
|
2287 a draft message. MH's mail storage consists of folders and messages,
|
|
meillo@58
|
2288 the messages named with ascending numbers. A draft message breaks with this
|
|
meillo@58
|
2289 concept by introducing a message in a file named
|
|
meillo@58
|
2290 .Fn draft .
|
|
meillo@58
|
2291 This draft
|
|
meillo@58
|
2292 message is special. It can not be simply listed with the available tools,
|
|
meillo@58
|
2293 but instead requires special switches. I.e. corner-cases were
|
|
meillo@58
|
2294 introduced. A draft folder, in contrast, does not introduce such
|
|
meillo@58
|
2295 corner-cases. The available tools can operate on the messages within that
|
|
meillo@58
|
2296 folder like on any messages within any mail folders. The only difference
|
|
meillo@58
|
2297 is the fact that the default folder for
|
|
meillo@58
|
2298 .Pn send
|
|
meillo@58
|
2299 is the draft folder,
|
|
meillo@58
|
2300 instead of the current folder, like for all other tools.
|
|
meillo@58
|
2301 .P
|
|
meillo@58
|
2302 The trivial part of the change was activating the draft folder facility
|
|
meillo@58
|
2303 by default and setting a default name for this folder. Obviously, I chose
|
|
meillo@58
|
2304 the name
|
|
meillo@58
|
2305 .Fn +drafts .
|
|
meillo@58
|
2306 This made the
|
|
meillo@82
|
2307 .Sw -draftfolder
|
|
meillo@58
|
2308 and
|
|
meillo@82
|
2309 .Sw -draftmessage
|
|
meillo@58
|
2310 switches useless, and I could remove them.
|
|
meillo@58
|
2311 The more difficult but also the part that showed the real improvement,
|
|
meillo@58
|
2312 was updating the tools to the new concept.
|
|
meillo@82
|
2313 .Sw -draft
|
|
meillo@58
|
2314 switches could
|
|
meillo@58
|
2315 be dropped, as operating on a draft message became indistinguishable to
|
|
meillo@58
|
2316 operating on any other message for the tools.
|
|
meillo@58
|
2317 .Pn comp
|
|
meillo@58
|
2318 still has its
|
|
meillo@82
|
2319 .Sw -use
|
|
meillo@58
|
2320 switch for switching between its two modes: (1) Compose a new
|
|
meillo@58
|
2321 draft, possibly by taking some existing message as a form. (2) Modify
|
|
meillo@58
|
2322 an existing draft. In either case, the behavior of
|
|
meillo@58
|
2323 .Pn comp is
|
|
meillo@58
|
2324 deterministic. There is no more need to query the user. I consider this
|
|
meillo@58
|
2325 a major improvement. By making
|
|
meillo@58
|
2326 .Pn send
|
|
meillo@58
|
2327 simply operate on the current
|
|
meillo@58
|
2328 message in the draft folder by default, with message and folder both
|
|
meillo@58
|
2329 overridable by specifying them on the command line, it is now possible
|
|
meillo@58
|
2330 to send a draft anywhere within the storage by simply specifying its folder
|
|
meillo@58
|
2331 and name.
|
|
meillo@58
|
2332 .P
|
|
meillo@58
|
2333 All theses changes converted special cases to regular cases, thus
|
|
meillo@58
|
2334 simplifying the tools and increasing the flexibility.
|
|
meillo@58
|
2335
|
|
meillo@58
|
2336
|
|
meillo@58
|
2337 .H2 "Trash Folder
|
|
meillo@58
|
2338 .P
|
|
meillo@58
|
2339 Similar to the situation for drafts is the situation for removed messages.
|
|
meillo@58
|
2340 Historically, a message was deleted by renaming. A specific
|
|
meillo@58
|
2341 \fIbackup prefix\fP, often comma (\c
|
|
meillo@58
|
2342 .Fn , )
|
|
meillo@58
|
2343 or hash (\c
|
|
meillo@58
|
2344 .Fn # ),
|
|
meillo@58
|
2345 being prepended to the file name. Thus, MH wouldn't recognize the file
|
|
meillo@58
|
2346 as a message anymore, as only files whose name consists of digits only
|
|
meillo@58
|
2347 are treated as messages. The removed messages remained as files in the
|
|
meillo@58
|
2348 same directory and needed some maintenance job to truly delete them after
|
|
meillo@58
|
2349 some grace time. Usually, by running a command similar to
|
|
meillo@82
|
2350 .VS
|
|
meillo@82
|
2351 find /home/user/Mail -ctime +7 -name ',*' | xargs rm
|
|
meillo@82
|
2352 VE
|
|
meillo@58
|
2353 in a cron job. Within the grace time interval
|
|
meillo@58
|
2354 the original message could be restored by stripping the
|
|
meillo@58
|
2355 the backup prefix from the file name. If however, the last message of
|
|
meillo@58
|
2356 a folder is been removed \(en say message
|
|
meillo@58
|
2357 .Fn 6
|
|
meillo@58
|
2358 becomes file
|
|
meillo@58
|
2359 .Fn ,6
|
|
meillo@58
|
2360 \(en and a new message enters the same folder, thus the same
|
|
meillo@58
|
2361 numbered being given again \(en in our case
|
|
meillo@58
|
2362 .Fn 6
|
|
meillo@58
|
2363 \(en, if that one
|
|
meillo@58
|
2364 is removed too, then the backup of the former message gets overwritten.
|
|
meillo@58
|
2365 Thus, the ability to restore removed messages does not only depend on
|
|
meillo@58
|
2366 the ``sweeping cron job'' but also on the removing of further messages.
|
|
meillo@58
|
2367 This is undesirable, because the real mechanism is hidden from the user
|
|
meillo@58
|
2368 and the consequences of further removals are not always obvious.
|
|
meillo@58
|
2369 Further more, the backup files are scattered within the whole mail
|
|
meillo@58
|
2370 storage, instead of being collected at one place.
|
|
meillo@58
|
2371 .P
|
|
meillo@58
|
2372 To improve the situation, the profile entry
|
|
meillo@58
|
2373 .Pe rmmproc
|
|
meillo@58
|
2374 (previously named
|
|
meillo@58
|
2375 .Pe Delete-Prog )
|
|
meillo@58
|
2376 was introduced, very early.
|
|
meillo@58
|
2377 It could be set to any command, which would care for the mail removal
|
|
meillo@58
|
2378 instead of taking the default action, described above.
|
|
meillo@58
|
2379 Refiling the to-be-removed files to some garbage folder was a common
|
|
meillo@58
|
2380 example. Nmh's man page
|
|
meillo@58
|
2381 .Mp rmm(1)
|
|
meillo@58
|
2382 proposes
|
|
meillo@58
|
2383 .Cl "refile +d
|
|
meillo@58
|
2384 to move messages to the garbage folder and
|
|
meillo@58
|
2385 .Cl "rm `mhpath +d all`
|
|
meillo@58
|
2386 the empty the garbage folder.
|
|
meillo@58
|
2387 Managing the message removal this way is a sane approach. It keeps
|
|
meillo@58
|
2388 the removed messages in one place, makes it easy to remove the backup
|
|
meillo@58
|
2389 files, and, most important, enables the user to use the tools of MH
|
|
meillo@58
|
2390 itself to operate on the removed messages. One can
|
|
meillo@58
|
2391 .Pn scan
|
|
meillo@58
|
2392 them,
|
|
meillo@58
|
2393 .Pn show
|
|
meillo@58
|
2394 them, and restore them with
|
|
meillo@58
|
2395 .Pn refile .
|
|
meillo@58
|
2396 There's no more
|
|
meillo@58
|
2397 need to use
|
|
meillo@58
|
2398 .Pn mhpath
|
|
meillo@58
|
2399 to switch over from MH tools to Unix tools \(en MH can do it all itself.
|
|
meillo@58
|
2400 .P
|
|
meillo@58
|
2401 This approach matches perfect with the concepts of MH, thus making
|
|
meillo@58
|
2402 it powerful. Hence, I made it the default. And even more, I also
|
|
meillo@58
|
2403 removed the old backup prefix approach, as it is clearly less powerful.
|
|
meillo@58
|
2404 Keeping unused alternative in the code is a bad choice as they likely
|
|
meillo@58
|
2405 gather bugs, by not being constantly tested. Also, the increased code
|
|
meillo@58
|
2406 size and more conditions crease the maintenance costs. By strictly
|
|
meillo@58
|
2407 converting to the trash folder approach, I simplified the code base.
|
|
meillo@58
|
2408 .Pn rmm
|
|
meillo@58
|
2409 calls
|
|
meillo@58
|
2410 .Pn refile
|
|
meillo@58
|
2411 internally to move the to-be-removed
|
|
meillo@58
|
2412 message to the trash folder (\c
|
|
meillo@58
|
2413 .Fn +trash
|
|
meillo@58
|
2414 by default). Messages
|
|
meillo@58
|
2415 there can be operated on like on any other message in the storage.
|
|
meillo@58
|
2416 The sweep clean, one can use
|
|
meillo@82
|
2417 .Cl "rmm -unlink +trash a" ,
|
|
meillo@58
|
2418 where the
|
|
meillo@82
|
2419 .Sw -unlink
|
|
meillo@58
|
2420 switch causes the files to be truly unliked instead
|
|
meillo@58
|
2421 of moved to the trash folder.
|
|
meillo@58
|
2422
|
|
meillo@58
|
2423
|
|
meillo@58
|
2424 .H2 "Path Notations
|
|
meillo@58
|
2425 .P
|
|
meillo@58
|
2426 foo
|
|
meillo@58
|
2427
|
|
meillo@58
|
2428
|
|
meillo@58
|
2429 .H2 "MIME Integration
|
|
meillo@58
|
2430 .P
|
|
meillo@58
|
2431 user-visible access to whole messages and MIME parts are inherently
|
|
meillo@58
|
2432 different
|
|
meillo@58
|
2433
|
|
meillo@58
|
2434
|
|
meillo@58
|
2435 .H2 "Of One Cast
|
|
meillo@58
|
2436 .P
|
