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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
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7
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8
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9
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10 .H1 "Stream-lining
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11
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12 .P
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13 MH had been considered an all-in-one system for mail handling.
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14 The community around nmh has a similar understanding.
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15 In fundamental difference, should be a MUA only.
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16 I believe that all-in-one mail systems are obsolete.
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17 There are excellent specialized MTAs, like Postfix;
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18 there are specialized MDAs, like Procmail; there are specialized
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19 MRAs, like Fetchmail. I believe it's best to use them instead of
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20 providing the same function ourselves. Doing something well, requires to
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21 focus on a small set of aspects. The more
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22 it is possible to focus, the better the result in this particular
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23 area will be. Usually, the limiting resource in Free Software
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24 community development is man power.
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25 If the development power is even spread over a large
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26 development area, it becomes more difficult to
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27 compete with the specialists in the various fields. This is even
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28 increased, given the small community \(en developers and users \(en
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29 that MH-based mail systems have. In consequence, I believe that the
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30 available resources should be focused to the point where MH is
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31 most unique. This is clearly the MUA part.
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32 .P
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33 The goal for mmh was to remove peripheral parts and stream-line
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34 it for the MUA task.
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35
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36
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37 .H2 "Removal of Mail Transfer Facilities
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38 .P
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39 In contrast to nmh, which also provides mail submission and mail retrieval
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40 facilities, mmh is a MUA only.
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41 This general difference in the view on the character of nmh
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42 initiated the development of mmh.
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43 Removing the mail transfer facilities had been the first work task
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44 in the mmh project.
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45 .P
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46 The MSA is called \fIMessage Transfer Service\fP (MTS) in nmh.
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47 The facility established network connections and spoke SMTP to submit
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48 messages for relay to the outside world.
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49 This part was implemented by the
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50 .Pn post
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51 command.
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52 The changes in emailing
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53 demanded changes in this part of nmh in the last years.
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54 Encryption and authetication for network connections
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55 needed to be supported, hence TLS and SASL were introduced
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56 into nmh. This added complexity to the nmh without improving it in
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57 its core functions. Also, keeping up with recent developments in
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58 this field requires development power and specialists.
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59 For mmh this whole facility was cut off.
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60 .Ci f6aa95b724fd8c791164abe7ee5468bf5c34f226
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61 .Ci fecd5d34f65597a4dfa16aeabea7d74b191532c3
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62 .Ci 156d35f6425bea4c1ed3c4c79783dc613379c65b
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63 Instead, mmh depends on an external MTA.
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64 The only outgoing interface available to mmh is the
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65 .Pn sendmail
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66 command.
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67 Almost any MTA provides a
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68 .Pn sendmail
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69 command.
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70 If not, any program can be substituted if it reads the
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71 message from the standard input, extracts the recipient addresses
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72 from the message header and does not conflict
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73 with sendmail-specific command line options.
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74 .P
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75 To retrieve mail, the
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76 .Pn inc
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77 command established network connections
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78 and spoke POP3 to retrieve mail from remote servers.
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79 As with mail submission, the network connections required encryption and
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80 authentication, thus TLS and SASL was added.
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81 As POP3 becomes more and more superseded by IMAP, support for message
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82 retrieval through IMAP will become necessary to be added soon, too.
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83 Mmh has dropped the support for retrieving mail from remote locations.
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84 .Ci ab7b48411962d26439f92f35ed084d3d6275459c
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85 Instead, it depends on an external tool to cover this task.
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86 There exist two paths for messages to enter mmh's mail storage:
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87 They can be incorporate with
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88 .Pn inc
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89 from the system maildrop, or
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90 .Pn rcvstore
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91 reads them from the standard input.
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92 .P
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93 With the removal of the MSA and MRA, mmh converted from an all-in-one
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94 mail system to being only a MUA.
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95 Following the Unix philosophy, it focuses on one job and
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96 tries to do that one well.
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97 Not only the programs follow that tenet but also the project itself does so.
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98 Now, of course, mmh depends on third-party software.
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99 An external MTA/MSA is required to transfer mail to the outside world;
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100 an external MRA is required to retrieve mail from remote machines.
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101 There exist excellent implementations of such software,
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102 which do this specific task likely better than the internal
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103 versions had done it. Also, the best suiting programs can be freely chosen.
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104 .P
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105 As it had already been possible to use an external MSA or MRA,
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106 why not keep the internal version for convenience?
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107 The question whether there is sense in having a fall-back pager in all
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108 the command line tools, for the cases when
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109 .Pn more
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110 or
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111 .Pn less
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112 aren't available, appears to be ridiculous.
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113 Now, an MSA or MRA is clearly more complex than a text pager,
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114 and not necessarily available but still the concept holds:
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115 design the system orthogonally.
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116 If it is conceptionally more elegant to have the MTA to be a separate tool
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117 \(en as the RFCs propose this split, this is likely the case \(en
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118 then separate.
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119 .P
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120 Further more, if programs become complex, they should be split;
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121 and if projects become complex, they should be split, too.
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122 Essential complexity is defined by the problem.
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123 Decades ago, emailing had been small and simple.
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124 (\c
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125 .Pn /bin/mail
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126 had once covered anything there was to email and still had been small
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127 and simple.)
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128 Then the essential complexity of email increased.
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129 Email tools needed to react.
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130 In nmh, for instance, the POP server, which the original MH had included,
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131 was removed.
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132 Now is the time to go one step further and remove the MSA and MRA.
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133 Not only does it decrease the code amount of the project,
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134 but more important, it removes the whole field of message transfer
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135 with all its implications for the project.
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136 It removes the need to adjust to any changes concerning network transfer.
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137 This independence is received by depending on an external program
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138 that covers the field.
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139 Today, this is a reasonable exchange.
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140 .P
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141 To add some kind of function, there's always the choice
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142 among implementing the function in the project directly,
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143 depending on a library that provides the function, or depending on
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144 a program that provides the function.
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145 Whereas adding the function directly to the project increases the
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146 code size most and requires most maintenance and development work,
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147 it makes the project most independent.
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148 Using libraries or external programs require less
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149 maintenance work.
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150 Programs have the smallest interfaces, providing the most separation
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151 but possibly limiting the information exchange.
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152 External libraries are stronger connected than external programs but
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153 allow better information exchange.
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154 Adding more code to a project does always increase maintenance work.
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155 Implementing complex functions directly in the project will add
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156 a lot of code. This should be avoided if possible.
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157 Hence, the dependencies only change in kind, not in their existence.
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158 In mmh, library dependencies on
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159 .Pn libsasl2
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160 and
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161 .Pn libcrypto /\c
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162 .Pn libssl
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163 were treated against program dependencies on an MSA and an MRA.
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164 Besides program dependencies providing the stronger separation
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165 and being more flexible, they also allowed
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166 over 6\|000 lines of code to be removed from mmh.
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167 This made mmh's code base about 12\|% smaller.
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168 Reducing the projects code size by such an amount without actually
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169 losing function is a convincing argument.
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170 Actually, as external MSAs and MRAs are likely better
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171 than the project's internal version, the user even gains functionality.
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172 .P
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173 Users of MH should not have problems to set up an external MSA and MRA.
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174 Also, the popular MSAs and MRAs have large communities and a lot
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175 of documentation available.
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176 Choices for MSAs range from the full-featured
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177 .I Postfix
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178 over mid-size solutions like
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179 .I masqmail
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180 and
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181 .I dma
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182 to small forwarders like
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183 .I ssmtp
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184 and
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185 .I nullmailer .
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186 Choices for MRAs include
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187 .I fetchmail ,
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188 .I getmail ,
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189 .I mpop
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190 and
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191 .I fdm .
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192
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193
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194 .H2 "Removal of non-MUA Tools
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195 .P
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196 Some MH tools were removed because they didn't add to the MUA's job.
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197 It is a design goal of mmh to remove the parts that are rarely used.
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198 The project shall become more stream-lined and focused.
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199 Rarely used and loosely related tools distract from the lean appearance.
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200 They require maintenance work without adding to the core task.
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201 In mmh the following tools are not available anymore:
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202 .BU
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203 .Pn conflict
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204 was removed because it is a mail system maintenance tool.
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205 .Ci 8b235097cbd11d728c07b966cf131aa7133ce5a9
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206 Besides, it even checks
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207 .Fn /etc/passwd
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208 and
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209 .Fn /etc/group
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210 for consistency, which has nothing at all to do with emailing.
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211 The tool might be useful, but it should not be shipped with mmh.
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212 .\" XXX historic reasons?
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213 .BU
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214 .Pn rcvtty
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215 was removed because its usecase of writing to the user's terminal
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216 on receiving of mail is obsolete.
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217 .Ci 14767c94b3827be7c867196467ed7aea5f6f49b0
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218 If users like to be
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219 informed of new mail, the shell's
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220 .Ev MAILPATH
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221 variable or graphical notifications are more appealing.
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222 Writing directly to a terminals is hardly ever wanted today.
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223 If though one wants to have it this way, the standard tool
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224 .Pn write
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225 can be used in a way similar to:
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226 .VS
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227 scan -file - | write `id -un`
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228 VE
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229 .BU
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230 .Pn viamail
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231 was removed when the new attachment system was activated, because
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232 .Pn forw
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233 could then cover the task itself.
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234 .Ci eda72d6a7a7c20ff123043fb7f19c509ea01f932
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235 The program
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236 .Pn sendfiles
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237 was rewritten as a shell script wrapper around
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238 .Pn forw .
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239 .Ci 0e82199cf3c991a173e0ac8aa776efdb3ded61e6
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240 .BU
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241 .Pn msgchk
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242 was removed, because it lost its use case when POP support was removed.
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243 .Ci bb9360ead7eb7a3fedcce2eeedfc660014e41dbe
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244 A call to
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245 .Pn msgchk
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246 provided hardly more information than
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247 .VS
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248 ls -l /var/mail/meillo
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249 VE
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250 though it distinguished between old and new mail.
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251 This detail information and can be retrieved with
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252 .Pn stat (1),
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253 too.
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254 A very small shell script could be written to output the information
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255 in a similar way, if truly necessary.
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256 As mmh's
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257 .Pn inc
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258 only incorporates mail from the user's local maildrop
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259 and thus no data transfers over slow networks are involved,
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260 there's hardly any need to check for new mail before incorporating it.
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261 .BU
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262 .Pn msh
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263 was removed because the tool was in conflict with the philosophy of MH.
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264 .Ci 916690191222433a6923a4be54b0d8f6ac01bd02
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265 It provided an interactive shell to access the features of MH,
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266 but it wasn't just a shell, tailored to the needs of mail handling.
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267 Instead it was one large program that had several MH tools built in.
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268 This conflicts with the major feature of MH of being a tool chest.
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269 .Pn msh 's
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270 main use case had been accessing Bulletin Boards, which have seized to
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271 be popular.
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272 .P
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273 Removing
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274 .Pn msh ,
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275 together with the truly archaic code relicts
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276 .Pn vmh
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277 and
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278 .Pn wmh ,
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279 saved more than 7\|000 lines of C code \(en
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280 about 15\|% of the project's original source code amount.
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281 .P
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282 Having less code (with equal readability, of course)
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283 for the same functionality is an advantage.
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284 Less code means less bugs and less maintenance work.
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285 As
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286 .Pn rcvtty
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287 and
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288 .Pn msgchk
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289 are rarely used and can be implemented in different ways,
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290 then why should one keep them?
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291 Removing them stream-lines mmh.
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292 .Pn viamail 's
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293 use case is now partly obsolete and partly covered by
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294 .Pn forw ,
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295 hence there's no reason to still maintain it.
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296 .Pn conflict
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297 is not related to the mail client, and
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298 .Pn msh
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299 conflicts with the basic concept of MH.
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300 Theses two tools might still be useful, but they should not be part of mmh.
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301 .P
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302 Finally, there's
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303 .Pn slocal .
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304 .Pn slocal
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305 is an MDA and thus not directly MUA-related.
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meillo@78
|
306 It should be removed, because including it is a violation
|
|
meillo@78
|
307 of the idea that mmh is a MUA only.
|
|
meillo@78
|
308 It should become a separate project.
|
|
meillo@76
|
309 But
|
|
meillo@76
|
310 .Pn slocal
|
|
meillo@76
|
311 provides rule-based processing of messages, like filing them into
|
|
meillo@76
|
312 different folders, which is otherwise not available in mmh.
|
|
meillo@76
|
313 Further more,
|
|
meillo@76
|
314 .Pn slocal
|
|
meillo@76
|
315 does neither pull dependencies nor a whole new technical area
|
|
meillo@76
|
316 into the project.
|
|
meillo@76
|
317 (See section XXX for the removing of the ndbm dependency.)
|
|
meillo@76
|
318 Still,
|
|
meillo@76
|
319 .Pn slocal
|
|
meillo@76
|
320 accounts for about 1\|000 lines of code that need to be maintained.
|
|
meillo@76
|
321 As
|
|
meillo@76
|
322 .Pn slocal
|
|
meillo@76
|
323 is almost self-standing, it should be split off into a separate project.
|
|
meillo@76
|
324 This would cut the strong connection between the MUA mmh and the MDA
|
|
meillo@76
|
325 .Pn slocal .
|
|
meillo@76
|
326 The MDA would become an alternative to
|
|
meillo@76
|
327 .I procmail ,
|
|
meillo@76
|
328 as it would no longer be the need to install a complete MH system, too.
|
|
meillo@76
|
329 Likewise, mmh users could decide to use
|
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meillo@76
|
330 .I procmail
|
|
meillo@76
|
331 without having a second, unused MDA (\c
|
|
meillo@76
|
332 .Pn slocal )
|
|
meillo@76
|
333 installed.
|
|
meillo@76
|
334 That's conceptionally the best solution.
|
|
meillo@76
|
335 Yet,
|
|
meillo@76
|
336 .Pn slocal
|
|
meillo@78
|
337 was not removed.
|
|
meillo@78
|
338 I feel unsure with the removal.
|
|
meillo@78
|
339 Hence, the decision over
|
|
meillo@78
|
340 .Pn slocal
|
|
meillo@78
|
341 is deferred.
|
|
meillo@78
|
342 This does not hurt because
|
|
meillo@78
|
343 .Pn slocal
|
|
meillo@78
|
344 is completely unrelated to the rest of mmh.
|
|
meillo@0
|
345
|
|
meillo@58
|
346
|
|
meillo@76
|
347 .H2 "\fLshow\fP and \fPmhshow\fP
|
|
meillo@58
|
348 .P
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|
meillo@69
|
349 Since the very beginning \(en already in the first concept paper \(en
|
|
meillo@58
|
350 .Pn show
|
|
meillo@62
|
351 had been MH's message display program.
|
|
meillo@58
|
352 .Pn show
|
|
meillo@76
|
353 mapped message numbers and sequences to files and invoked
|
|
meillo@58
|
354 .Pn mhl
|
|
meillo@76
|
355 to have the files formated.
|
|
meillo@76
|
356 For MIME, this approach wasn't sufficient anymore.
|
|
meillo@58
|
357 MIME messages can consist of multiple parts, some of which aren't
|
|
meillo@62
|
358 directly displayable, and text content might be encoded in
|
|
meillo@58
|
359 foreign charsets.
|
|
meillo@58
|
360 .Pn show 's
|
|
meillo@76
|
361 understanding of messages and
|
|
meillo@58
|
362 .Pn mhl 's
|
|
meillo@58
|
363 limited display facilities couldn't cope with the task any longer.
|
|
meillo@62
|
364 .P
|
|
meillo@76
|
365 Instead of extending these tools, additional tools were written from scratch
|
|
meillo@58
|
366 and then added to the MH tool chest. Doing so is encouraged by the
|
|
meillo@58
|
367 tool chest approach. The new tools could be added without interfering
|
|
meillo@78
|
368 with the existing ones.
|
|
meillo@78
|
369 Modular design is a great advantage for extending a system.
|
|
meillo@62
|
370 First, the new MIME features were added in form of the single program
|
|
meillo@58
|
371 .Pn mhn .
|
|
meillo@58
|
372 The command
|
|
meillo@82
|
373 .Cl "mhn -show 42
|
|
meillo@58
|
374 would show the MIME message numbered 42.
|
|
meillo@58
|
375 With the 1.0 release of nmh in February 1999, Richard Coleman finished
|
|
meillo@58
|
376 the split of
|
|
meillo@58
|
377 .Pn mhn
|
|
meillo@58
|
378 into a set of specialized programs, which together covered the
|
|
meillo@62
|
379 multiple aspects of MIME. One of these resulting tools was
|
|
meillo@69
|
380 .Pn mhshow ,
|
|
meillo@69
|
381 which replaced the
|
|
meillo@82
|
382 .Cl "mhn -show
|
|
meillo@62
|
383 call.
|
|
meillo@76
|
384 It was capable to display a MIME message appropriately.
|
|
meillo@62
|
385 .P
|
|
meillo@76
|
386 From then on, two message display tools were part of nmh:
|
|
meillo@76
|
387 .Pn show
|
|
meillo@76
|
388 and
|
|
meillo@76
|
389 .Pn mhshow .
|
|
meillo@76
|
390 Because the user should not need to invoke the right tool
|
|
meillo@69
|
391 whether the message uses MIME or not,
|
|
meillo@69
|
392 .Pn show
|
|
meillo@69
|
393 was extended to automatically hand the job over to
|
|
meillo@69
|
394 .Pn mhshow
|
|
meillo@69
|
395 if displaying the message would be beyond
|
|
meillo@69
|
396 .Pn show 's
|
|
meillo@69
|
397 abilities.
|
|
meillo@69
|
398 In consequence, the user would invoke
|
|
meillo@69
|
399 .Pn show
|
|
meillo@69
|
400 (possibly through
|
|
meillo@69
|
401 .Pn next
|
|
meillo@69
|
402 or
|
|
meillo@69
|
403 .Pn prev )
|
|
meillo@69
|
404 and get the message printed with either
|
|
meillo@69
|
405 .Pn show
|
|
meillo@69
|
406 or
|
|
meillo@69
|
407 .Pn mhshow ,
|
|
meillo@69
|
408 whatever was more appropriate.
|
|
meillo@69
|
409 (There was also a switch for
|
|
meillo@69
|
410 .Pn show
|
|
meillo@69
|
411 to never invoke
|
|
meillo@76
|
412 .Pn mhshow .
|
|
meillo@76
|
413 .Pn show
|
|
meillo@76
|
414 was able to display MIME messages if they contained only a single text
|
|
meillo@76
|
415 part.)
|
|
meillo@69
|
416 .P
|
|
meillo@69
|
417 Having two similar tools for essentially the same task is redundant.
|
|
meillo@76
|
418 The development of both programs needed to be in sync,
|
|
meillo@76
|
419 to ensure that the programs behaved in a similar way,
|
|
meillo@76
|
420 because they were used like a single tool.
|
|
meillo@76
|
421 Different behavior would have surprised the user.
|
|
meillo@69
|
422 .P
|
|
meillo@69
|
423 Today, non-MIME messages are rather seen to be a special case of
|
|
meillo@69
|
424 MIME messages, than MIME messages are seen to be an extension to
|
|
meillo@76
|
425 original email.
|
|
meillo@69
|
426 As
|
|
meillo@69
|
427 .Pn mhshow
|
|
meillo@69
|
428 had already be able to display non-MIME messages, it was natural
|
|
meillo@69
|
429 to drop
|
|
meillo@69
|
430 .Pn show
|
|
meillo@69
|
431 in favor of using
|
|
meillo@69
|
432 .Pn mhshow
|
|
meillo@69
|
433 exclusively.
|
|
meillo@76
|
434 This decision followed the idea of orthogonal design.
|
|
meillo@76
|
435 For convenience,
|
|
meillo@76
|
436 .Pn mhshow
|
|
meillo@76
|
437 was then renamed to
|
|
meillo@76
|
438 .Pn show .
|
|
meillo@72
|
439 .Ci 4c1efddfd499300c7e74263e57d8aa137e84c853
|
|
meillo@69
|
440 .P
|
|
meillo@76
|
441 To prepare for this transition,
|
|
meillo@69
|
442 .Pn mhshow
|
|
meillo@69
|
443 was reworked to behave more like
|
|
meillo@69
|
444 .Pn show
|
|
meillo@69
|
445 first.
|
|
meillo@76
|
446 (Section XXX describes this rework from a different perspective.)
|
|
meillo@69
|
447 Once the tools behaved similar, the replacing became a natural decision.
|
|
meillo@69
|
448 In mmh,
|
|
meillo@69
|
449 .Pn show
|
|
meillo@69
|
450 is the one single message display program again, but it handles
|
|
meillo@69
|
451 MIME messages as well as non-MIME messages.
|
|
meillo@76
|
452 Now, there's only one program to maintain, and users don't need to deal
|
|
meillo@69
|
453 with the existance of two display programs.
|
|
meillo@69
|
454 .P
|
|
meillo@76
|
455 There's one reason why removing the old
|
|
meillo@69
|
456 .Pn show
|
|
meillo@69
|
457 hurts: It had been such a simple program.
|
|
meillo@69
|
458 Its lean elegance is missing to
|
|
meillo@69
|
459 .Pn mhshow ,
|
|
meillo@69
|
460 i.e. the new
|
|
meillo@69
|
461 .Pn show .
|
|
meillo@69
|
462 But there is no chance, because supporting MIME causes essentially
|
|
meillo@69
|
463 higher complexity.
|
|
meillo@58
|
464
|
|
meillo@58
|
465
|
|
meillo@58
|
466 .H2 "Removal of Configure Options
|
|
meillo@58
|
467 .P
|
|
meillo@76
|
468 Customization is a double-edged sword.
|
|
meillo@76
|
469 It allows better suiting setups, but not for free.
|
|
meillo@76
|
470 There is the cost of code complexity to be able to customize.
|
|
meillo@76
|
471 There is the cost of less tested setups, because there are
|
|
meillo@72
|
472 more possible setups and especially corner-cases.
|
|
meillo@76
|
473 And, there is the cost of choice itself.
|
|
meillo@76
|
474 The code complexity directly affects the developers.
|
|
meillo@72
|
475 Less tested code affects both, users and developers.
|
|
meillo@76
|
476 The problem of choice affects the users, for once by having to
|
|
meillo@76
|
477 choose, but also by complexer interfaces that require more documentation.
|
|
meillo@72
|
478 Whenever options add little advantages, they should be considered for
|
|
meillo@72
|
479 removal.
|
|
meillo@72
|
480 I have reduced the number of project-specific configure options from
|
|
meillo@72
|
481 fifteen to three.
|
|
meillo@74
|
482
|
|
meillo@76
|
483 .U3 "Mail Transfer Facilities
|
|
meillo@74
|
484 .P
|
|
meillo@72
|
485 With the removal of the mail transfer facilities five option vanished:
|
|
meillo@72
|
486 .IP \f(CW--with-mts=[smtp|sendmail]\fP
|
|
meillo@72
|
487 Specified the default mail transport service, which now is sendmail always.
|
|
meillo@72
|
488 .IP \f(CW--with-smtpservers=[server1...]\fP
|
|
meillo@72
|
489 Specified the default SMTP servers for the smtp mail transfer service.
|
|
meillo@72
|
490 .Ci 128545e06224233b7e91fc4c83f8830252fe16c9
|
|
meillo@72
|
491 .IP \f(CW--with-cyrus-sasl\fP
|
|
meillo@72
|
492 Enabled SASL support for mail transfer.
|
|
meillo@72
|
493 .IP \f(CW--with-tls\fP
|
|
meillo@72
|
494 Enabled TLS support for mail transfer.
|
|
meillo@72
|
495 .IP \f(CW--enable-pop\fP
|
|
meillo@72
|
496 Enabled the message retrieval facility.
|
|
meillo@72
|
497
|
|
meillo@74
|
498 .U3 "Backup Prefix
|
|
meillo@74
|
499 .P
|
|
meillo@76
|
500 The backup prefix is the string that was prepended to message
|
|
meillo@76
|
501 filenames to tag them as deleted.
|
|
meillo@76
|
502 By default it had been the comma character `\f(CW,\fP'.
|
|
meillo@78
|
503 In July 2000, Kimmo Suominen introduced
|
|
meillo@78
|
504 the configure option
|
|
meillo@78
|
505 .Sw --with-hash-backup
|
|
meillo@78
|
506 to change the default to the hash symbol `\f(CW#\fP'.
|
|
meillo@78
|
507 The choice was probably personal preference, because first, the
|
|
meillo@78
|
508 option was named
|
|
meillo@78
|
509 .Sw --with-backup-prefix.
|
|
meillo@78
|
510 and had the prefix symbol as argument.
|
|
meillo@78
|
511 Because giving the hash symbol as argument caused to many problems
|
|
meillo@78
|
512 for configure,
|
|
meillo@78
|
513 the option was limited to use the hash symbol as the default prefix.
|
|
meillo@78
|
514 This makes me believe, that the choice for the hash was personal preference.
|
|
meillo@78
|
515 Being it related or not, words that start with the hash symbol
|
|
meillo@78
|
516 introduce a comment in the Unix shell.
|
|
meillo@72
|
517 Thus, the command line
|
|
meillo@72
|
518 .Cl "rm #13 #15
|
|
meillo@72
|
519 calls
|
|
meillo@72
|
520 .Pn rm
|
|
meillo@72
|
521 without arguments because the first hash symbol starts the comment
|
|
meillo@72
|
522 that reaches until the end of the line.
|
|
meillo@72
|
523 To delete the backup files,
|
|
meillo@72
|
524 .Cl "rm ./#13 ./#15"
|
|
meillo@72
|
525 needs to be used.
|
|
meillo@78
|
526 Using the hash as backup prefix can be seen as a precaution agains
|
|
meillo@78
|
527 data loss.
|
|
meillo@78
|
528 .P
|
|
meillo@72
|
529 I removed the configure option but added the profile entry
|
|
meillo@72
|
530 .Pe backup-prefix ,
|
|
meillo@72
|
531 which allows to specify an arbitrary string as backup prefix.
|
|
meillo@72
|
532 .Ci 6c40d481d661d532dd527eaf34cebb6d3f8ed086
|
|
meillo@76
|
533 Profile entries are the common method to change mmh's behavior.
|
|
meillo@76
|
534 This change did not remove the choice but moved it to a location where
|
|
meillo@72
|
535 it suited better.
|
|
meillo@76
|
536 .P
|
|
meillo@78
|
537 Eventually, however, the new trash folder concept
|
|
meillo@78
|
538 .Cf "Sec. XXX
|
|
meillo@78
|
539 obsoleted the concept of the backup prefix completely.
|
|
meillo@78
|
540 .Ci 8edc5aaf86f9f77124664f6801bc6c6cdf258173
|
|
meillo@72
|
541 (Well, there still are corner-cases to remove until the backup
|
|
meillo@72
|
542 prefix can be layed to rest, eventually.)
|
|
meillo@72
|
543 .\" FIXME: Do this work in the code!
|
|
meillo@76
|
544
|
|
meillo@76
|
545 .U3 "Editor and Pager
|
|
meillo@74
|
546 .P
|
|
meillo@74
|
547 The two configure options
|
|
meillo@74
|
548 .CW --with-editor=EDITOR
|
|
meillo@74
|
549 .CW --with-pager=PAGER
|
|
meillo@74
|
550 were used to specify the default editor and pager at configure time.
|
|
meillo@74
|
551 Doing so at configure time made sense in the Eighties,
|
|
meillo@76
|
552 when the set of available editors and pagers varied much across
|
|
meillo@76
|
553 different systems.
|
|
meillo@76
|
554 Today, the situation is more homegeneic.
|
|
meillo@74
|
555 The programs
|
|
meillo@74
|
556 .Pn vi
|
|
meillo@74
|
557 and
|
|
meillo@74
|
558 .Pn more
|
|
meillo@76
|
559 can be expected to be available on every Unix system,
|
|
meillo@74
|
560 as they are specified by POSIX since two decades.
|
|
meillo@74
|
561 (The specifications for
|
|
meillo@74
|
562 .Pn vi
|
|
meillo@74
|
563 and
|
|
meillo@74
|
564 .Pn more
|
|
meillo@74
|
565 appeared in
|
|
meillo@74
|
566 .[
|
|
meillo@74
|
567 posix 1987
|
|
meillo@74
|
568 .]
|
|
meillo@74
|
569 and,
|
|
meillo@74
|
570 .[
|
|
meillo@74
|
571 posix 1992
|
|
meillo@74
|
572 .]
|
|
meillo@74
|
573 respectively.)
|
|
meillo@74
|
574 As a first step, these two tools were hard-coded as defaults.
|
|
meillo@74
|
575 .Ci 5d43a99db70c12a673028c7758c20cbe3e13ef5f
|
|
meillo@74
|
576 Not changed were the
|
|
meillo@74
|
577 .Pe editor
|
|
meillo@74
|
578 and
|
|
meillo@74
|
579 .Pe moreproc
|
|
meillo@76
|
580 profile entries, which allowed the user to override the system defaults.
|
|
meillo@74
|
581 Later, the concept was reworked to respect the standard environment
|
|
meillo@74
|
582 variables
|
|
meillo@74
|
583 .Ev VISUAL
|
|
meillo@74
|
584 and
|
|
meillo@74
|
585 .Ev PAGER
|
|
meillo@76
|
586 if they are set.
|
|
meillo@74
|
587 Today, mmh determines the editor to use in the following order,
|
|
meillo@74
|
588 taking the first available and non-empty item:
|
|
meillo@74
|
589 .IP (1)
|
|
meillo@74
|
590 Environment variable
|
|
meillo@74
|
591 .Ev MMHEDITOR
|
|
meillo@74
|
592 .IP (2)
|
|
meillo@74
|
593 Profile entry
|
|
meillo@74
|
594 .Pe Editor
|
|
meillo@74
|
595 .IP (3)
|
|
meillo@74
|
596 Environment variable
|
|
meillo@74
|
597 .Ev VISUAL
|
|
meillo@74
|
598 .IP (4)
|
|
meillo@74
|
599 Environment variable
|
|
meillo@74
|
600 .Ev EDITOR
|
|
meillo@74
|
601 .IP (5)
|
|
meillo@74
|
602 Command
|
|
meillo@74
|
603 .Pn vi .
|
|
meillo@74
|
604 .P
|
|
meillo@76
|
605 .Ci f85f4b7ae62e3d05a945dcd46ead51f0a2a89a9b
|
|
meillo@76
|
606 .P
|
|
meillo@76
|
607 The pager to use is deteminded in a similar order,
|
|
meillo@74
|
608 also taking the first available and non-empty item:
|
|
meillo@74
|
609 .IP (1)
|
|
meillo@74
|
610 Environment variable
|
|
meillo@74
|
611 .Ev MMHPAGER
|
|
meillo@74
|
612 .IP (2)
|
|
meillo@74
|
613 Profile entry
|
|
meillo@74
|
614 .Pe Pager
|
|
meillo@74
|
615 (replaces
|
|
meillo@74
|
616 .Pe moreproc )
|
|
meillo@74
|
617 .IP (3)
|
|
meillo@74
|
618 Environment variable
|
|
meillo@74
|
619 .Ev PAGER
|
|
meillo@74
|
620 .IP (4)
|
|
meillo@74
|
621 Command
|
|
meillo@74
|
622 .Pn more .
|
|
meillo@74
|
623 .P
|
|
meillo@74
|
624 .Ci 0c4214ea2aec6497d0d67b436bbee9bc1d225f1e
|
|
meillo@74
|
625 .P
|
|
meillo@76
|
626 By respecting the
|
|
meillo@74
|
627 .Ev VISUAL /\c
|
|
meillo@74
|
628 .Ev EDITOR
|
|
meillo@74
|
629 and
|
|
meillo@74
|
630 .Ev PAGER
|
|
meillo@76
|
631 environment variables,
|
|
meillo@76
|
632 the new behavior confirms better to the common style on Unix systems.
|
|
meillo@76
|
633 Additionally, the new approach is more uniform and clearer to users.
|
|
meillo@72
|
634
|
|
meillo@74
|
635 .U3 "Locale
|
|
meillo@74
|
636 .P
|
|
meillo@74
|
637 The configure option
|
|
meillo@74
|
638 .Sw --disable-locale
|
|
meillo@74
|
639 was removed because today there's hardly any need to disable locale
|
|
meillo@74
|
640 support.
|
|
meillo@74
|
641 .Ci ccf4f175ef4c4e7522f9510a4a1149c15d810dd9
|
|
meillo@72
|
642
|
|
meillo@76
|
643 .U3 "ndbm
|
|
meillo@72
|
644 .P
|
|
meillo@74
|
645 .Pn slocal
|
|
meillo@78
|
646 used to depend on
|
|
meillo@74
|
647 .I ndbm ,
|
|
meillo@74
|
648 a database library.
|
|
meillo@76
|
649 The database is used to store the `\fLMessage-ID\fP's of all
|
|
meillo@76
|
650 messages delivered.
|
|
meillo@74
|
651 This enables
|
|
meillo@74
|
652 .Pn slocal
|
|
meillo@74
|
653 to suppress delivering the same message to the same user twice.
|
|
meillo@74
|
654 (This features was enabled by the
|
|
meillo@74
|
655 .Sw -suppressdup
|
|
meillo@74
|
656 switch.)
|
|
meillo@74
|
657 .P
|
|
meillo@74
|
658 A variety of version of the database library exist.
|
|
meillo@78
|
659 .[
|
|
meillo@78
|
660 wolter unix incompat notes dbm
|
|
meillo@78
|
661 .]
|
|
meillo@74
|
662 Complicated autoconf code was needed to detect them correctly.
|
|
meillo@74
|
663 Further more, the configure switches
|
|
meillo@74
|
664 .Sw --with-ndbm=ARG
|
|
meillo@74
|
665 and
|
|
meillo@74
|
666 .Sw --with-ndbmheader=ARG
|
|
meillo@74
|
667 were added to help with difficult setups that would
|
|
meillo@78
|
668 not be detected automatically or correctly.
|
|
meillo@74
|
669 .P
|
|
meillo@74
|
670 By removing the suppress duplicates feature of
|
|
meillo@74
|
671 .Pn slocal ,
|
|
meillo@74
|
672 the dependency on
|
|
meillo@74
|
673 .I ndbm
|
|
meillo@78
|
674 vanished and 120 lines of complex autoconf code could be saved.
|
|
meillo@74
|
675 .Ci ecd6d6a20cb7a1507e3a20d6c4cb3a1cf14c6bbf
|
|
meillo@78
|
676 The change removed funtionality too, but that is minor to the
|
|
meillo@78
|
677 improvement by dropping the dependency and the complex autoconf code.
|
|
meillo@72
|
678
|
|
meillo@74
|
679 .U3 "mh-e Support
|
|
meillo@72
|
680 .P
|
|
meillo@74
|
681 The configure option
|
|
meillo@74
|
682 .Sw --disable-mhe
|
|
meillo@74
|
683 was removed when the mh-e support was reworked.
|
|
meillo@74
|
684 Mh-e is the Emacs front-end to MH.
|
|
meillo@76
|
685 It requires MH to provide minor additional functions.
|
|
meillo@76
|
686 The
|
|
meillo@76
|
687 .Sw --disable-mhe
|
|
meillo@76
|
688 configure option could switch these extensions off.
|
|
meillo@76
|
689 After removing the support for old versions of mh-e,
|
|
meillo@74
|
690 only the
|
|
meillo@74
|
691 .Sw -build
|
|
meillo@76
|
692 switches of
|
|
meillo@74
|
693 .Pn forw
|
|
meillo@74
|
694 and
|
|
meillo@74
|
695 .Pn repl
|
|
meillo@76
|
696 are left to be mh-e extensions.
|
|
meillo@76
|
697 They are now always built in because they add little code and complexity.
|
|
meillo@76
|
698 In consequence, the
|
|
meillo@74
|
699 .Sw --disable-mhe
|
|
meillo@76
|
700 configure option was removed
|
|
meillo@72
|
701 .Ci a7ce7b4a580d77b6c2c4d980812beb589aa4c643
|
|
meillo@74
|
702 Removing the option removed a second code setup that would have
|
|
meillo@74
|
703 needed to be tested.
|
|
meillo@76
|
704 This change was first done in nmh and thereafter merged into mmh.
|
|
meillo@76
|
705 .P
|
|
meillo@76
|
706 The interface changes in mmh require mh-e to be adjusted in order
|
|
meillo@76
|
707 to be able to use mmh as back-end.
|
|
meillo@76
|
708 This will require minor changes to mh-e, but removing the
|
|
meillo@76
|
709 .Sw -build
|
|
meillo@76
|
710 switches would require more rework.
|
|
meillo@72
|
711
|
|
meillo@74
|
712 .U3 "Masquerading
|
|
meillo@72
|
713 .P
|
|
meillo@74
|
714 The configure option
|
|
meillo@74
|
715 .Sw --enable-masquerade
|
|
meillo@76
|
716 could take up to three arguments:
|
|
meillo@76
|
717 `draft_from', `mmailid', and `username_extension'.
|
|
meillo@74
|
718 They activated different types of address masquerading.
|
|
meillo@74
|
719 All of them were implemented in the SMTP-speaking
|
|
meillo@74
|
720 .Pn post
|
|
meillo@76
|
721 command, which provided an MSA.
|
|
meillo@76
|
722 Address masquerading is an MTA's task and mmh does not cover
|
|
meillo@76
|
723 this field anymore.
|
|
meillo@76
|
724 Hence, true masquerading needs to be implemented in the external MTA.
|
|
meillo@74
|
725 .P
|
|
meillo@74
|
726 The
|
|
meillo@74
|
727 .I mmailid
|
|
meillo@74
|
728 masquerading type is the oldest one of the three and the only one
|
|
meillo@74
|
729 available in the original MH.
|
|
meillo@74
|
730 It provided a
|
|
meillo@74
|
731 .I username
|
|
meillo@74
|
732 to
|
|
meillo@74
|
733 .I fakeusername
|
|
meillo@76
|
734 mapping, based on the password file's GECOS field.
|
|
meillo@74
|
735 The man page
|
|
meillo@74
|
736 .Mp mh-tailor(5)
|
|
meillo@74
|
737 described the use case as being the following:
|
|
meillo@74
|
738 .QP
|
|
meillo@74
|
739 This is useful if you want the messages you send to always
|
|
meillo@74
|
740 appear to come from the name of an MTA alias rather than your
|
|
meillo@74
|
741 actual account name. For instance, many organizations set up
|
|
meillo@74
|
742 `First.Last' sendmail aliases for all users. If this is
|
|
meillo@74
|
743 the case, the GECOS field for each user should look like:
|
|
meillo@74
|
744 ``First [Middle] Last <First.Last>''
|
|
meillo@74
|
745 .P
|
|
meillo@74
|
746 As mmh sends outgoing mail via the local MTA only,
|
|
meillo@76
|
747 the best location to do such global rewrites is there.
|
|
meillo@74
|
748 Besides, the MTA is conceptionally the right location because it
|
|
meillo@74
|
749 does the reverse mapping for incoming mail (aliasing), too.
|
|
meillo@76
|
750 Further more, masquerading set up there is readily available for all
|
|
meillo@74
|
751 mail software on the system.
|
|
meillo@76
|
752 Hence, mmailid masquerading was removed.
|
|
meillo@74
|
753 .Ci 0836c8000ccb34b59410ef1c15b1b7feac70ce5f
|
|
meillo@74
|
754 .P
|
|
meillo@74
|
755 The
|
|
meillo@74
|
756 .I username_extension
|
|
meillo@76
|
757 masquerading type did not replace the username but would append a suffix,
|
|
meillo@76
|
758 specified by the
|
|
meillo@74
|
759 .Ev USERNAME_EXTENSION
|
|
meillo@76
|
760 environment variable, to it.
|
|
meillo@76
|
761 This provided support for the
|
|
meillo@74
|
762 .I user-extension
|
|
meillo@74
|
763 feature of qmail and the similar
|
|
meillo@74
|
764 .I "plussed user
|
|
meillo@74
|
765 processing of sendmail.
|
|
meillo@74
|
766 The decision to remove this username_extension masquerading was
|
|
meillo@74
|
767 motivated by the fact that
|
|
meillo@74
|
768 .Pn spost
|
|
meillo@76
|
769 hadn't supported it already.
|
|
meillo@76
|
770 .Ci 2abae0bfd0ad5bf898461e50aa4b466d641f23d9
|
|
meillo@76
|
771 Username extensions are possible in mmh, but less convenient to use.
|
|
meillo@76
|
772 .\" XXX format file %(getenv USERNAME_EXTENSION)
|
|
meillo@74
|
773 .P
|
|
meillo@74
|
774 The
|
|
meillo@74
|
775 .I draft_from
|
|
meillo@74
|
776 masquerading type instructed
|
|
meillo@74
|
777 .Pn post
|
|
meillo@84
|
778 to use the value of the
|
|
meillo@84
|
779 .Hd From
|
|
meillo@84
|
780 header field as SMTP envelope sender.
|
|
meillo@76
|
781 Sender addresses could be replaced completely.
|
|
meillo@74
|
782 .Ci b14ea6073f77b4359aaf3fddd0e105989db9
|
|
meillo@76
|
783 Mmh offers a kind of masquerading similar in effect, but
|
|
meillo@74
|
784 with technical differences.
|
|
meillo@76
|
785 As mmh does not transfer messages itself, the local MTA has final control
|
|
meillo@76
|
786 over the sender's address. Any masquerading mmh introduces may be reverted
|
|
meillo@76
|
787 by the MTA.
|
|
meillo@76
|
788 In times of pedantic spam checking, an MTA will take care to use
|
|
meillo@76
|
789 sensible envelope sender addresses to keep its own reputation up.
|
|
meillo@84
|
790 Nonetheless, the MUA can set the
|
|
meillo@84
|
791 .Hd From
|
|
meillo@84
|
792 header field and thereby propose
|
|
meillo@76
|
793 a sender address to the MTA.
|
|
meillo@74
|
794 The MTA may then decide to take that one or generate the canonical sender
|
|
meillo@74
|
795 address for use as envelope sender address.
|
|
meillo@74
|
796 .P
|
|
meillo@74
|
797 In mmh, the MTA will always extract the recipient and sender from the
|
|
meillo@84
|
798 message header (\c
|
|
meillo@74
|
799 .Pn sendmail 's
|
|
meillo@74
|
800 .Sw -t
|
|
meillo@74
|
801 switch).
|
|
meillo@84
|
802 The
|
|
meillo@84
|
803 .Hd From
|
|
meillo@84
|
804 header field of the draft may be set arbitrary by the user.
|
|
meillo@74
|
805 If it is missing, the canonical sender address will be generated by the MTA.
|
|
meillo@74
|
806
|
|
meillo@74
|
807 .U3 "Remaining Options
|
|
meillo@74
|
808 .P
|
|
meillo@74
|
809 Two configure options remain in mmh.
|
|
meillo@74
|
810 One is the locking method to use:
|
|
meillo@74
|
811 .Sw --with-locking=[dot|fcntl|flock|lockf] .
|
|
meillo@76
|
812 The idea of removing all methods except the portable dot locking
|
|
meillo@76
|
813 and having that one as the default is appealing, but this change
|
|
meillo@76
|
814 requires deeper technical investigation into the topic.
|
|
meillo@76
|
815 The other option,
|
|
meillo@74
|
816 .Sw --enable-debug ,
|
|
meillo@74
|
817 compiles the programs with debugging symbols and does not strip them.
|
|
meillo@74
|
818 This option is likely to stay.
|
|
meillo@72
|
819
|
|
meillo@72
|
820
|
|
meillo@58
|
821
|
|
meillo@63
|
822
|
|
meillo@58
|
823 .H2 "Removal of switches
|
|
meillo@58
|
824 .P
|
|
meillo@58
|
825
|
|
meillo@58
|
826
|
|
meillo@58
|
827
|
|
meillo@58
|
828
|
|
meillo@74
|
829 .H1 "Modernizing
|
|
meillo@58
|
830
|
|
meillo@58
|
831
|
|
meillo@58
|
832 .H2 "Removal of Code Relicts
|
|
meillo@0
|
833 .P
|
|
meillo@51
|
834 The code base of mmh originates from the late Seventies,
|
|
meillo@51
|
835 had been extensively
|
|
meillo@51
|
836 worked on in the mid Eighties, and had been partly reorganized and extended
|
|
meillo@51
|
837 in the Nineties. Relicts of all those times had gathered in the code base.
|
|
meillo@12
|
838 My goal was to remove any ancient code parts. One part of the task was
|
|
meillo@12
|
839 converting obsolete code constructs to standard constructs, the other part
|
|
meillo@12
|
840 was dropping obsolete functions.
|
|
meillo@12
|
841 .P
|
|
meillo@12
|
842 As I'm not even thirty years old and have no more than seven years of
|
|
meillo@51
|
843 Unix experience, I needed to learn about the history in retrospective.
|
|
meillo@51
|
844 Older people likely have used those ancient constructs themselves
|
|
meillo@51
|
845 and have suffered from their incompatibilities and have longed for
|
|
meillo@12
|
846 standardization. Unfortunately, I have only read that others had done so.
|
|
meillo@12
|
847 This put me in a much more difficult positions when working on the old
|
|
meillo@12
|
848 code. I needed to recherche what other would have known by heart from
|
|
meillo@12
|
849 experience. All my programming experience comes from a time past ANSI C
|
|
meillo@12
|
850 and past POSIX. Although I knew about the times before, I took the
|
|
meillo@51
|
851 current state implicitly for granted most of the time.
|
|
meillo@12
|
852 .P
|
|
meillo@12
|
853 Being aware of
|
|
meillo@12
|
854 these facts, I rather let people with more historic experience solve the
|
|
meillo@12
|
855 task of converting the ancient code constructs to standardized ones.
|
|
meillo@12
|
856 Luckily, Lyndon Nerenberg focused on this task at the nmh project.
|
|
meillo@12
|
857 He converted large parts of the code to POSIX constructs, removing
|
|
meillo@12
|
858 the conditionals compilation for now standardized features.
|
|
meillo@12
|
859 I'm thankful for this task being solved. I only pulled the changes into
|
|
meillo@12
|
860 mmh.
|
|
meillo@12
|
861 .P
|
|
meillo@20
|
862 The other task \(en dropping ancient functionality to remove old code \(en
|
|
meillo@12
|
863 I did myself, though. My position to strip mmh to the bare minimum of
|
|
meillo@12
|
864 frequently used features is much more revolutional than the nmh community
|
|
meillo@20
|
865 likes it. Without the need to justify my decisions, I was able to quickly
|
|
meillo@20
|
866 remove functionality I considered ancient.
|
|
meillo@20
|
867 The need to discuss my decisions with
|
|
meillo@20
|
868 peers likely would have slowed this process down. Of course, I researched
|
|
meillo@12
|
869 if a particular feature really should be dropped. Having not had any
|
|
meillo@12
|
870 contact to this feature within my computer life was a first indicator to
|
|
meillo@12
|
871 drop it, but I also asked others and searched the literature for modern
|
|
meillo@12
|
872 usage of the feature. If it appeared to be truly ancient, I dropped it.
|
|
meillo@12
|
873 The reason for dropping is always part of the commit message in the
|
|
meillo@12
|
874 version control system. Thus, it is easy for others to check their
|
|
meillo@12
|
875 view on the topic with mine and possibly to argue for reinclusion.
|
|
meillo@12
|
876
|
|
meillo@12
|
877 .U2 "MMDF maildrop support
|
|
meillo@12
|
878 .P
|
|
meillo@12
|
879 I did drop any support for the MMDF maildrop format. This type of format
|
|
meillo@12
|
880 is conceptionally similar to the mbox format, but uses four bytes with
|
|
meillo@12
|
881 value 1 (\fL^A^A^A^A\fP) as message delimiter,
|
|
meillo@18
|
882 instead of the string ``\fLFrom\ \fP''.
|
|
meillo@12
|
883 Due to the similarity and mbox being the de-facto standard maildrop
|
|
meillo@12
|
884 format on Unix, but also due to the larger influence of Sendmail than MMDF,
|
|
meillo@12
|
885 the MMDF maildrop format had vanished.
|
|
meillo@12
|
886 .P
|
|
meillo@12
|
887 The simplifications within the code were only moderate. Switches could
|
|
meillo@12
|
888 be removed from tools like
|
|
meillo@12
|
889 .L packf ,
|
|
meillo@12
|
890 which generate packed mailboxes. Only one packed mailbox format remained:
|
|
meillo@12
|
891 mbox.
|
|
meillo@12
|
892 The most important changes affect the equally named mail parsing routine in
|
|
meillo@12
|
893 .L sbr/m_getfld.c .
|
|
meillo@12
|
894 The direct MMDF code had been removed, but as now only one packed mailbox
|
|
meillo@12
|
895 format is left, code structure simplifications are likely possible.
|
|
meillo@12
|
896 The reason why they are still outstanding is the heavily optimized code
|
|
meillo@18
|
897 of
|
|
meillo@18
|
898 .Fu m_getfld() .
|
|
meillo@18
|
899 Changes beyond a small local scope \(en
|
|
meillo@12
|
900 which restructuring in its core is \(en cause a high risk of damaging
|
|
meillo@12
|
901 the intricate workings of the optimized code. This problem is know
|
|
meillo@12
|
902 to the developers of nmh, too. They also avoid touching this minefield
|
|
meillo@12
|
903 if possible.
|
|
meillo@12
|
904
|
|
meillo@12
|
905 .U2 "UUCP Bang Paths
|
|
meillo@12
|
906 .P
|
|
meillo@12
|
907 More questionably than the former topic is the removal of support for the
|
|
meillo@12
|
908 UUCP bang path address style. However, the user may translate the bang
|
|
meillo@12
|
909 paths on retrieval to Internet addresses and the other way on posting
|
|
meillo@12
|
910 messages. The former can be done my an MDA like procmail; the latter
|
|
meillo@12
|
911 by a sendmail wrapper. This would ensure that any address handling would
|
|
meillo@12
|
912 work as expected. However, it might just work well without any
|
|
meillo@12
|
913 such modifications, as mmh does not touch addresses much, in general.
|
|
meillo@12
|
914 But I can't ensure as I have never used an environment with bang paths.
|
|
meillo@12
|
915 Also, the behavior might break at any point in further development.
|
|
meillo@12
|
916
|
|
meillo@12
|
917 .U2 "Hardcopy terminal support
|
|
meillo@12
|
918 .P
|
|
meillo@12
|
919 More of a funny anecdote is the remaining of a check for printing to a
|
|
meillo@12
|
920 hardcopy terminal until Spring 2012, when I finally removed it.
|
|
meillo@12
|
921 I surely would be very happy to see such a terminal in action, maybe
|
|
meillo@12
|
922 actually being able to work on it, but I fear my chances are null.
|
|
meillo@12
|
923 .P
|
|
meillo@12
|
924 The check only prevented a pager to be placed between the outputting
|
|
meillo@18
|
925 program (\c
|
|
meillo@18
|
926 .Pn mhl )
|
|
meillo@18
|
927 and the terminal. This could have been ensured with
|
|
meillo@18
|
928 the
|
|
meillo@82
|
929 .Sw -nomoreproc
|
|
meillo@18
|
930 at the command line statically, too.
|
|
meillo@12
|
931
|
|
meillo@12
|
932 .U2 "Removed support for header fields
|
|
meillo@12
|
933 .P
|
|
meillo@84
|
934 The
|
|
meillo@84
|
935 .Hd Encrypted
|
|
meillo@84
|
936 header field had been introduced by RFC\^822, but already
|
|
meillo@12
|
937 marked legacy in RFC 2822. It was superseded by FIXME.
|
|
meillo@84
|
938 Mmh does no more support this header field.
|
|
meillo@12
|
939 .P
|
|
meillo@84
|
940 Native support for
|
|
meillo@84
|
941 .Hd Face
|
|
meillo@84
|
942 header fields had been removed, as well.
|
|
meillo@84
|
943 The feature is similar to the
|
|
meillo@84
|
944 .Hd X-Face
|
|
meillo@84
|
945 header field in its intent,
|
|
meillo@21
|
946 but takes a different approach to store the image.
|
|
meillo@84
|
947 Instead of encoding the image data directly into the header field,
|
|
meillo@84
|
948 the it contains the hostname and UDP port where the image
|
|
meillo@21
|
949 date could be retrieved.
|
|
meillo@84
|
950 Neither
|
|
meillo@84
|
951 .Hd X-Face
|
|
meillo@84
|
952 nor the here described
|
|
meillo@84
|
953 .Hd Face
|
|
meillo@84
|
954 system
|
|
meillo@21
|
955 \**
|
|
meillo@21
|
956 .FS
|
|
meillo@21
|
957 There is also a newer but different system, invented 2005,
|
|
meillo@84
|
958 using
|
|
meillo@84
|
959 .Hd Face
|
|
meillo@84
|
960 headers.
|
|
meillo@84
|
961 It is the successor of
|
|
meillo@84
|
962 .Hd X-Face
|
|
meillo@84
|
963 providing colored PNG images.
|
|
meillo@21
|
964 .FE
|
|
meillo@21
|
965 became well used in the large scale.
|
|
meillo@21
|
966 It's still possible to use a Face systems,
|
|
meillo@21
|
967 although mmh does not provide support for any of the different systems
|
|
meillo@21
|
968 anymore. It's fairly easy to write a small shell script to
|
|
meillo@21
|
969 extract the embedded or fetch the external Face data and display the image.
|
|
meillo@84
|
970 Own
|
|
meillo@84
|
971 .Hd Face
|
|
meillo@84
|
972 header field can be added into the draft template files.
|
|
meillo@21
|
973 .P
|
|
meillo@84
|
974 .Hd Content-MD5
|
|
meillo@84
|
975 header fields were introduced by RFC\^1864. They provide only
|
|
meillo@12
|
976 a verification of data corruption during the transfer. By no means can
|
|
meillo@12
|
977 they ensure verbatim end-to-end delivery of the contents. This is clearly
|
|
meillo@12
|
978 stated in the RFC. The proper approach to provide verificationability
|
|
meillo@12
|
979 of content in an end-to-end relationship is the use of digital cryptography
|
|
meillo@12
|
980 (RFCs FIXME). On the other hand, transfer protocols should ensure the
|
|
meillo@12
|
981 integrity of the transmission. In combinations these two approaches
|
|
meillo@84
|
982 make the
|
|
meillo@84
|
983 .Hd Content-MD5
|
|
meillo@84
|
984 header field useless. In consequence, I removed
|
|
meillo@12
|
985 the support for it. By this removal, MD5 computation is not needed
|
|
meillo@12
|
986 anywhere in mmh. Hence, over 500 lines of code were removed by this one
|
|
meillo@84
|
987 change. Even if the
|
|
meillo@84
|
988 .Hd Content-MD5
|
|
meillo@84
|
989 header field is useful sometimes,
|
|
meillo@12
|
990 I value its usefulnes less than the improvement in maintainability, caused
|
|
meillo@12
|
991 by the removal.
|
|
meillo@12
|
992
|
|
meillo@20
|
993 .U2 "Prompter's Control Keys
|
|
meillo@20
|
994 .P
|
|
meillo@20
|
995 The program
|
|
meillo@20
|
996 .Pn prompter
|
|
meillo@20
|
997 queries the user to fill in a message form. When used by
|
|
meillo@20
|
998 .Pn comp
|
|
meillo@20
|
999 as:
|
|
meillo@82
|
1000 .VS
|
|
meillo@82
|
1001 comp -editor prompter
|
|
meillo@82
|
1002 VE
|
|
meillo@20
|
1003 the resulting behavior is similar to
|
|
meillo@20
|
1004 .Pn mailx .
|
|
meillo@51
|
1005 Apparently,
|
|
meillo@20
|
1006 .Pn prompter
|
|
meillo@20
|
1007 hadn't been touched lately. Otherwise it's hardly explainable why it
|
|
meillo@20
|
1008 still offered the switches
|
|
meillo@84
|
1009 .Sw -erase
|
|
meillo@84
|
1010 .Ar chr
|
|
meillo@20
|
1011 and
|
|
meillo@84
|
1012 .Sw -kill
|
|
meillo@84
|
1013 .Ar chr
|
|
meillo@20
|
1014 to name the characters for command line editing.
|
|
meillo@21
|
1015 The times when this had been necessary are long time gone.
|
|
meillo@20
|
1016 Today these things work out-of-the-box, and if not, are configured
|
|
meillo@20
|
1017 with the standard tool
|
|
meillo@20
|
1018 .Pn stty .
|
|
meillo@20
|
1019
|
|
meillo@21
|
1020 .U2 "Vfork and Retry Loops
|
|
meillo@21
|
1021 .P
|
|
meillo@51
|
1022 MH creates many processes, which is a consequence of the tool chest approach.
|
|
meillo@21
|
1023 In earlier times
|
|
meillo@21
|
1024 .Fu fork()
|
|
meillo@21
|
1025 had been an expensive system call, as the process's whole image needed
|
|
meillo@21
|
1026 to be duplicated. One common case is replacing the image with
|
|
meillo@21
|
1027 .Fu exec()
|
|
meillo@21
|
1028 right after having forked the child process.
|
|
meillo@21
|
1029 To speed up this case, the
|
|
meillo@21
|
1030 .Fu vfork()
|
|
meillo@21
|
1031 system call was invented at Berkeley. It completely omits copying the
|
|
meillo@21
|
1032 image. If the image gets replaced right afterwards then unnecessary
|
|
meillo@21
|
1033 work is omited. On old systems this results in large speed ups.
|
|
meillo@21
|
1034 MH uses
|
|
meillo@21
|
1035 .Fu vfork()
|
|
meillo@21
|
1036 whenever possible.
|
|
meillo@21
|
1037 .P
|
|
meillo@21
|
1038 Memory management units that support copy-on-write semantics make
|
|
meillo@21
|
1039 .Fu fork()
|
|
meillo@21
|
1040 almost as fast as
|
|
meillo@21
|
1041 .Fu vfork()
|
|
meillo@21
|
1042 in the cases when they can be exchanged.
|
|
meillo@21
|
1043 With
|
|
meillo@21
|
1044 .Fu vfork()
|
|
meillo@51
|
1045 being more error-prone and hardly faster, it's preferable to simply
|
|
meillo@21
|
1046 use
|
|
meillo@21
|
1047 .Fu fork()
|
|
meillo@21
|
1048 instead.
|
|
meillo@21
|
1049 .P
|
|
meillo@21
|
1050 Related to the costs of
|
|
meillo@21
|
1051 .Fu fork()
|
|
meillo@21
|
1052 is the probability of its success.
|
|
meillo@21
|
1053 Today on modern systems, the system call will succeed almost always.
|
|
meillo@51
|
1054 In the Eighties on heavy loaded systems, as they were common at
|
|
meillo@21
|
1055 universities, this had been different. Thus, many of the
|
|
meillo@21
|
1056 .Fu fork()
|
|
meillo@21
|
1057 calls were wrapped into loops to retry to fork several times in
|
|
meillo@21
|
1058 short intervals, in case of previous failure.
|
|
meillo@21
|
1059 In mmh, the program aborts at once if the fork failed.
|
|
meillo@21
|
1060 The user can reexecute the command then. This is expected to be a
|
|
meillo@21
|
1061 very rare case on modern systems, especially personal ones, which are
|
|
meillo@21
|
1062 common today.
|
|
meillo@21
|
1063
|
|
meillo@12
|
1064
|
|
meillo@58
|
1065 .H2 "Attachments
|
|
meillo@22
|
1066 .P
|
|
meillo@58
|
1067 MIME
|
|
meillo@58
|
1068
|
|
meillo@58
|
1069
|
|
meillo@58
|
1070 .H2 "Digital Cryptography
|
|
meillo@22
|
1071 .P
|
|
meillo@58
|
1072 Signing and encryption.
|
|
meillo@58
|
1073
|
|
meillo@58
|
1074
|
|
meillo@58
|
1075 .H2 "Good Defaults
|
|
meillo@22
|
1076 .P
|
|
meillo@58
|
1077 foo
|
|
meillo@58
|
1078
|
|
meillo@58
|
1079
|
|
meillo@58
|
1080
|
|
meillo@58
|
1081
|
|
meillo@58
|
1082 .H1 "Code style
|
|
meillo@22
|
1083 .P
|
|
meillo@58
|
1084 foo
|
|
meillo@58
|
1085
|
|
meillo@58
|
1086
|
|
meillo@58
|
1087 .H2 "Standard Code
|
|
meillo@22
|
1088 .P
|
|
meillo@58
|
1089 POSIX
|
|
meillo@22
|
1090
|
|
meillo@22
|
1091
|
|
meillo@58
|
1092 .H2 "Separation
|
|
meillo@14
|
1093
|
|
meillo@58
|
1094 .U2 "MH Directory Split
|
|
meillo@0
|
1095 .P
|
|
meillo@19
|
1096 In MH and nmh, a personal setup had consisted of two parts:
|
|
meillo@19
|
1097 The MH profile, named
|
|
meillo@19
|
1098 .Fn \&.mh_profile
|
|
meillo@19
|
1099 and being located directly in the user's home directory.
|
|
meillo@19
|
1100 And the MH directory, where all his mail messages and also his personal
|
|
meillo@19
|
1101 forms, scan formats, other configuration files are stored. The location
|
|
meillo@19
|
1102 of this directory could be user-chosen. The default was to name it
|
|
meillo@19
|
1103 .Fn Mail
|
|
meillo@19
|
1104 and have it directly in the home directory.
|
|
meillo@19
|
1105 .P
|
|
meillo@19
|
1106 I've never liked the data storage and the configuration to be intermixed.
|
|
meillo@19
|
1107 They are different kinds of data. One part, are the messages,
|
|
meillo@19
|
1108 which are the data to operate on. The other part, are the personal
|
|
meillo@19
|
1109 configuration files, which are able to change the behavior of the operations.
|
|
meillo@19
|
1110 The actual operations are defined in the profile, however.
|
|
meillo@19
|
1111 .P
|
|
meillo@19
|
1112 When storing data, one should try to group data by its type.
|
|
meillo@19
|
1113 There's sense in the Unix file system hierarchy, where configuration
|
|
meillo@19
|
1114 file are stored separate (\c
|
|
meillo@19
|
1115 .Fn /etc )
|
|
meillo@19
|
1116 to the programs (\c
|
|
meillo@19
|
1117 .Fn /bin
|
|
meillo@19
|
1118 and
|
|
meillo@19
|
1119 .Fn /usr/bin )
|
|
meillo@19
|
1120 to their sources (\c
|
|
meillo@19
|
1121 .Fn /usr/src ).
|
|
meillo@19
|
1122 Such separation eases the backup management, for instance.
|
|
meillo@19
|
1123 .P
|
|
meillo@19
|
1124 In mmh, I've reorganized the file locations.
|
|
meillo@19
|
1125 Still there are two places:
|
|
meillo@19
|
1126 There's the mail storage directory, which, like in MH, contains all the
|
|
meillo@19
|
1127 messages, but, unlike in MH, nothing else.
|
|
meillo@19
|
1128 Its location still is user-chosen, with the default name
|
|
meillo@19
|
1129 .Fn Mail ,
|
|
meillo@19
|
1130 in the user's home directory. This is much similar to the case in nmh.
|
|
meillo@19
|
1131 The configuration files, however, are grouped together in the new directory
|
|
meillo@19
|
1132 .Fn \&.mmh
|
|
meillo@19
|
1133 in the user's home directory.
|
|
meillo@19
|
1134 The user's profile now is a file, named
|
|
meillo@19
|
1135 .Fn profile ,
|
|
meillo@19
|
1136 in this mmh directory.
|
|
meillo@19
|
1137 Consistently, the context file and all the personal forms, scan formats,
|
|
meillo@19
|
1138 and the like, are also there.
|
|
meillo@19
|
1139 .P
|
|
meillo@19
|
1140 The naming changed with the relocation.
|
|
meillo@19
|
1141 The directory where everything, except the profile, had been stored (\c
|
|
meillo@19
|
1142 .Fn $HOME/Mail ),
|
|
meillo@19
|
1143 used to be called \fIMH directory\fP. Now, this directory is called the
|
|
meillo@19
|
1144 user's \fImail storage\fP. The name \fImmh directory\fP is now given to
|
|
meillo@19
|
1145 the new directory
|
|
meillo@19
|
1146 (\c
|
|
meillo@19
|
1147 .Fn $HOME/.mmh ),
|
|
meillo@19
|
1148 containing all the personal configuration files.
|
|
meillo@19
|
1149 .P
|
|
meillo@19
|
1150 The separation of the files by type of content is logical and convenient.
|
|
meillo@19
|
1151 There are no functional differences as any possible setup known to me
|
|
meillo@19
|
1152 can be implemented with both approaches, although likely a bit easier
|
|
meillo@19
|
1153 with the new approach. The main goal of the change had been to provide
|
|
meillo@19
|
1154 sensible storage locations for any type of personal mmh file.
|
|
meillo@19
|
1155 .P
|
|
meillo@19
|
1156 In order for one user to have multiple MH setups, he can use the
|
|
meillo@19
|
1157 environment variable
|
|
meillo@19
|
1158 .Ev MH
|
|
meillo@19
|
1159 the point to a different profile file.
|
|
meillo@19
|
1160 The MH directory (mail storage plus personal configuration files) is
|
|
meillo@19
|
1161 defined by the
|
|
meillo@19
|
1162 .Pe Path
|
|
meillo@19
|
1163 profile entry.
|
|
meillo@19
|
1164 The context file could be defined by the
|
|
meillo@19
|
1165 .Pe context
|
|
meillo@19
|
1166 profile entry or by the
|
|
meillo@19
|
1167 .Ev MHCONTEXT
|
|
meillo@19
|
1168 environment variable.
|
|
meillo@19
|
1169 The latter is useful to have a distinct context (e.g. current folders)
|
|
meillo@19
|
1170 in each terminal window, for instance.
|
|
meillo@19
|
1171 In mmh, there are three environment variables now.
|
|
meillo@19
|
1172 .Ev MMH
|
|
meillo@19
|
1173 may be used to change the location of the mmh directory.
|
|
meillo@19
|
1174 .Ev MMHP
|
|
meillo@19
|
1175 and
|
|
meillo@19
|
1176 .Ev MMHC
|
|
meillo@19
|
1177 change the profile and context files, respectively.
|
|
meillo@19
|
1178 Besides providing a more consistent feel (which simply is the result
|
|
meillo@19
|
1179 of being designed anew), the set of personal configuration files can
|
|
meillo@19
|
1180 be chosen independently from the profile (including mail storage location)
|
|
meillo@19
|
1181 and context, now. Being it relevant for practical use or not, it
|
|
meillo@19
|
1182 de-facto is an improvement. However, the main achievement is the
|
|
meillo@19
|
1183 split between mail storage and personal configuration files.
|
|
meillo@17
|
1184
|
|
meillo@0
|
1185
|
|
meillo@58
|
1186 .H2 "Modularization
|
|
meillo@0
|
1187 .P
|
|
meillo@58
|
1188 whatnowproc
|
|
meillo@0
|
1189 .P
|
|
meillo@49
|
1190 The \fIMH library\fP
|
|
meillo@49
|
1191 .Fn libmh.a
|
|
meillo@49
|
1192 collects a bunch of standard functions that many of the MH tools need,
|
|
meillo@49
|
1193 like reading the profile or context files.
|
|
meillo@49
|
1194 This doesn't hurt the separation.
|
|
meillo@49
|
1195
|
|
meillo@58
|
1196
|
|
meillo@58
|
1197 .H2 "Style
|
|
meillo@58
|
1198 .P
|
|
meillo@58
|
1199 Code layout, goto, ...
|
|
meillo@58
|
1200
|
|
meillo@58
|
1201
|
|
meillo@58
|
1202
|
|
meillo@58
|
1203
|
|
meillo@58
|
1204 .H1 "Concept Exploitation/Homogeniety
|
|
meillo@58
|
1205
|
|
meillo@58
|
1206
|
|
meillo@58
|
1207 .H2 "Draft Folder
|
|
meillo@58
|
1208 .P
|
|
meillo@58
|
1209 Historically, MH provided exactly one draft message, named
|
|
meillo@58
|
1210 .Fn draft
|
|
meillo@58
|
1211 and
|
|
meillo@58
|
1212 being located in the MH directory. When starting to compose another message
|
|
meillo@58
|
1213 before the former one was sent, the user had been questioned whether to use,
|
|
meillo@58
|
1214 refile or replace the old draft. Working on multiple drafts at the same time
|
|
meillo@58
|
1215 was impossible. One could only work on them in alteration by refiling the
|
|
meillo@58
|
1216 previous one to some directory and fetching some other one for reediting.
|
|
meillo@58
|
1217 This manual draft management needed to be done each time the user wanted
|
|
meillo@58
|
1218 to switch between editing one draft to editing another.
|
|
meillo@58
|
1219 .P
|
|
meillo@58
|
1220 To allow true parallel editing of drafts, in a straight forward way, the
|
|
meillo@58
|
1221 draft folder facility exists. It had been introduced already in July 1984
|
|
meillo@58
|
1222 by Marshall T. Rose. The facility was deactivated by default.
|
|
meillo@58
|
1223 Even in nmh, the draft folder facility remained deactivated by default.
|
|
meillo@58
|
1224 At least, Richard Coleman added the man page
|
|
meillo@58
|
1225 .Mp mh-draft(5)
|
|
meillo@58
|
1226 to document
|
|
meillo@58
|
1227 the feature well.
|
|
meillo@58
|
1228 .P
|
|
meillo@58
|
1229 The only advantage of not using the draft folder facility is the static
|
|
meillo@58
|
1230 name of the draft file. This could be an issue for MH frontends like mh-e.
|
|
meillo@58
|
1231 But as they likely want to provide working on multiple drafts in parallel,
|
|
meillo@58
|
1232 the issue is only concerning compatibility. The aim of nmh to stay compatible
|
|
meillo@58
|
1233 prevented the default activation of the draft folder facility.
|
|
meillo@58
|
1234 .P
|
|
meillo@58
|
1235 On the other hand, a draft folder is the much more natural concept than
|
|
meillo@58
|
1236 a draft message. MH's mail storage consists of folders and messages,
|
|
meillo@58
|
1237 the messages named with ascending numbers. A draft message breaks with this
|
|
meillo@58
|
1238 concept by introducing a message in a file named
|
|
meillo@58
|
1239 .Fn draft .
|
|
meillo@58
|
1240 This draft
|
|
meillo@58
|
1241 message is special. It can not be simply listed with the available tools,
|
|
meillo@58
|
1242 but instead requires special switches. I.e. corner-cases were
|
|
meillo@58
|
1243 introduced. A draft folder, in contrast, does not introduce such
|
|
meillo@58
|
1244 corner-cases. The available tools can operate on the messages within that
|
|
meillo@58
|
1245 folder like on any messages within any mail folders. The only difference
|
|
meillo@58
|
1246 is the fact that the default folder for
|
|
meillo@58
|
1247 .Pn send
|
|
meillo@58
|
1248 is the draft folder,
|
|
meillo@58
|
1249 instead of the current folder, like for all other tools.
|
|
meillo@58
|
1250 .P
|
|
meillo@58
|
1251 The trivial part of the change was activating the draft folder facility
|
|
meillo@58
|
1252 by default and setting a default name for this folder. Obviously, I chose
|
|
meillo@58
|
1253 the name
|
|
meillo@58
|
1254 .Fn +drafts .
|
|
meillo@58
|
1255 This made the
|
|
meillo@82
|
1256 .Sw -draftfolder
|
|
meillo@58
|
1257 and
|
|
meillo@82
|
1258 .Sw -draftmessage
|
|
meillo@58
|
1259 switches useless, and I could remove them.
|
|
meillo@58
|
1260 The more difficult but also the part that showed the real improvement,
|
|
meillo@58
|
1261 was updating the tools to the new concept.
|
|
meillo@82
|
1262 .Sw -draft
|
|
meillo@58
|
1263 switches could
|
|
meillo@58
|
1264 be dropped, as operating on a draft message became indistinguishable to
|
|
meillo@58
|
1265 operating on any other message for the tools.
|
|
meillo@58
|
1266 .Pn comp
|
|
meillo@58
|
1267 still has its
|
|
meillo@82
|
1268 .Sw -use
|
|
meillo@58
|
1269 switch for switching between its two modes: (1) Compose a new
|
|
meillo@58
|
1270 draft, possibly by taking some existing message as a form. (2) Modify
|
|
meillo@58
|
1271 an existing draft. In either case, the behavior of
|
|
meillo@58
|
1272 .Pn comp is
|
|
meillo@58
|
1273 deterministic. There is no more need to query the user. I consider this
|
|
meillo@58
|
1274 a major improvement. By making
|
|
meillo@58
|
1275 .Pn send
|
|
meillo@58
|
1276 simply operate on the current
|
|
meillo@58
|
1277 message in the draft folder by default, with message and folder both
|
|
meillo@58
|
1278 overridable by specifying them on the command line, it is now possible
|
|
meillo@58
|
1279 to send a draft anywhere within the storage by simply specifying its folder
|
|
meillo@58
|
1280 and name.
|
|
meillo@58
|
1281 .P
|
|
meillo@58
|
1282 All theses changes converted special cases to regular cases, thus
|
|
meillo@58
|
1283 simplifying the tools and increasing the flexibility.
|
|
meillo@58
|
1284
|
|
meillo@58
|
1285
|
|
meillo@58
|
1286 .H2 "Trash Folder
|
|
meillo@58
|
1287 .P
|
|
meillo@58
|
1288 Similar to the situation for drafts is the situation for removed messages.
|
|
meillo@58
|
1289 Historically, a message was deleted by renaming. A specific
|
|
meillo@58
|
1290 \fIbackup prefix\fP, often comma (\c
|
|
meillo@58
|
1291 .Fn , )
|
|
meillo@58
|
1292 or hash (\c
|
|
meillo@58
|
1293 .Fn # ),
|
|
meillo@58
|
1294 being prepended to the file name. Thus, MH wouldn't recognize the file
|
|
meillo@58
|
1295 as a message anymore, as only files whose name consists of digits only
|
|
meillo@58
|
1296 are treated as messages. The removed messages remained as files in the
|
|
meillo@58
|
1297 same directory and needed some maintenance job to truly delete them after
|
|
meillo@58
|
1298 some grace time. Usually, by running a command similar to
|
|
meillo@82
|
1299 .VS
|
|
meillo@82
|
1300 find /home/user/Mail -ctime +7 -name ',*' | xargs rm
|
|
meillo@82
|
1301 VE
|
|
meillo@58
|
1302 in a cron job. Within the grace time interval
|
|
meillo@58
|
1303 the original message could be restored by stripping the
|
|
meillo@58
|
1304 the backup prefix from the file name. If however, the last message of
|
|
meillo@58
|
1305 a folder is been removed \(en say message
|
|
meillo@58
|
1306 .Fn 6
|
|
meillo@58
|
1307 becomes file
|
|
meillo@58
|
1308 .Fn ,6
|
|
meillo@58
|
1309 \(en and a new message enters the same folder, thus the same
|
|
meillo@58
|
1310 numbered being given again \(en in our case
|
|
meillo@58
|
1311 .Fn 6
|
|
meillo@58
|
1312 \(en, if that one
|
|
meillo@58
|
1313 is removed too, then the backup of the former message gets overwritten.
|
|
meillo@58
|
1314 Thus, the ability to restore removed messages does not only depend on
|
|
meillo@58
|
1315 the ``sweeping cron job'' but also on the removing of further messages.
|
|
meillo@58
|
1316 This is undesirable, because the real mechanism is hidden from the user
|
|
meillo@58
|
1317 and the consequences of further removals are not always obvious.
|
|
meillo@58
|
1318 Further more, the backup files are scattered within the whole mail
|
|
meillo@58
|
1319 storage, instead of being collected at one place.
|
|
meillo@58
|
1320 .P
|
|
meillo@58
|
1321 To improve the situation, the profile entry
|
|
meillo@58
|
1322 .Pe rmmproc
|
|
meillo@58
|
1323 (previously named
|
|
meillo@58
|
1324 .Pe Delete-Prog )
|
|
meillo@58
|
1325 was introduced, very early.
|
|
meillo@58
|
1326 It could be set to any command, which would care for the mail removal
|
|
meillo@58
|
1327 instead of taking the default action, described above.
|
|
meillo@58
|
1328 Refiling the to-be-removed files to some garbage folder was a common
|
|
meillo@58
|
1329 example. Nmh's man page
|
|
meillo@58
|
1330 .Mp rmm(1)
|
|
meillo@58
|
1331 proposes
|
|
meillo@58
|
1332 .Cl "refile +d
|
|
meillo@58
|
1333 to move messages to the garbage folder and
|
|
meillo@58
|
1334 .Cl "rm `mhpath +d all`
|
|
meillo@58
|
1335 the empty the garbage folder.
|
|
meillo@58
|
1336 Managing the message removal this way is a sane approach. It keeps
|
|
meillo@58
|
1337 the removed messages in one place, makes it easy to remove the backup
|
|
meillo@58
|
1338 files, and, most important, enables the user to use the tools of MH
|
|
meillo@58
|
1339 itself to operate on the removed messages. One can
|
|
meillo@58
|
1340 .Pn scan
|
|
meillo@58
|
1341 them,
|
|
meillo@58
|
1342 .Pn show
|
|
meillo@58
|
1343 them, and restore them with
|
|
meillo@58
|
1344 .Pn refile .
|
|
meillo@58
|
1345 There's no more
|
|
meillo@58
|
1346 need to use
|
|
meillo@58
|
1347 .Pn mhpath
|
|
meillo@58
|
1348 to switch over from MH tools to Unix tools \(en MH can do it all itself.
|
|
meillo@58
|
1349 .P
|
|
meillo@58
|
1350 This approach matches perfect with the concepts of MH, thus making
|
|
meillo@58
|
1351 it powerful. Hence, I made it the default. And even more, I also
|
|
meillo@58
|
1352 removed the old backup prefix approach, as it is clearly less powerful.
|
|
meillo@58
|
1353 Keeping unused alternative in the code is a bad choice as they likely
|
|
meillo@58
|
1354 gather bugs, by not being constantly tested. Also, the increased code
|
|
meillo@58
|
1355 size and more conditions crease the maintenance costs. By strictly
|
|
meillo@58
|
1356 converting to the trash folder approach, I simplified the code base.
|
|
meillo@58
|
1357 .Pn rmm
|
|
meillo@58
|
1358 calls
|
|
meillo@58
|
1359 .Pn refile
|
|
meillo@58
|
1360 internally to move the to-be-removed
|
|
meillo@58
|
1361 message to the trash folder (\c
|
|
meillo@58
|
1362 .Fn +trash
|
|
meillo@58
|
1363 by default). Messages
|
|
meillo@58
|
1364 there can be operated on like on any other message in the storage.
|
|
meillo@58
|
1365 The sweep clean, one can use
|
|
meillo@82
|
1366 .Cl "rmm -unlink +trash a" ,
|
|
meillo@58
|
1367 where the
|
|
meillo@82
|
1368 .Sw -unlink
|
|
meillo@58
|
1369 switch causes the files to be truly unliked instead
|
|
meillo@58
|
1370 of moved to the trash folder.
|
|
meillo@58
|
1371
|
|
meillo@58
|
1372
|
|
meillo@58
|
1373 .H2 "Path Notations
|
|
meillo@58
|
1374 .P
|
|
meillo@58
|
1375 foo
|
|
meillo@58
|
1376
|
|
meillo@58
|
1377
|
|
meillo@58
|
1378 .H2 "MIME Integration
|
|
meillo@58
|
1379 .P
|
|
meillo@58
|
1380 user-visible access to whole messages and MIME parts are inherently
|
|
meillo@58
|
1381 different
|
|
meillo@58
|
1382
|
|
meillo@58
|
1383
|
|
meillo@58
|
1384 .H2 "Of One Cast
|
|
meillo@58
|
1385 .P
|
