--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/code/cut.c__system_iii.1980-04-11	Tue May 12 06:46:59 2015 +0200
@@ -0,0 +1,123 @@
+#
+/* cut : cut and paste columns of a table (projection of a relation)  (GWRL) */
+/* Release 1.5; handles single backspaces as produced by nroff    */
+# include <stdio.h>	/* make: cc cut.c */
+# define NFIELDS 512	/* max no of fields or resulting line length */
+# define BACKSPACE 8
+main(argc, argv)
+int argc; char **argv;
+{
+	int del = '\t';
+	int i, j, count, poscnt, r, s, t;
+	int endflag, supflag, cflag, fflag, backflag, filenr;
+	int sel[NFIELDS];
+	register int c;
+	register char *p1;
+	char *p2, outbuf[NFIELDS];
+	FILE *inptr;
+ 
+ 
+while (argc > 1 && argv[1][0] == '-'){
+	for (i = 1; (c = argv[1][i]) != '\0'; i++) {
+		switch(c) {
+			case 'd' : del = argv[1][++i];
+				if (del == '\0') diag("no delimiter\n");
+				break;
+			case 's': supflag++ ;
+				break;
+			case 'c': cflag++ ;
+				break;
+			case 'f': fflag++ ;
+				break;
+			default : diag("Usage: cut [-s] [-d<char>] {-c<list> | -f<list>} file ...\n");
+				break;
+		}
+		if (!endflag && (cflag || fflag)) {
+			endflag = 1;
+			r = s = t = 0;
+			do {	c = argv[1][++i];
+				switch(c) {
+					case '-' : if (r) diagl();
+						r = 1;
+						if (t == 0)  s = 1;
+						else {s = t; t = 0;}
+						continue;
+					case '\0' :
+					case ','  : if (t >= NFIELDS) diagl();
+						if (r) { if (t == 0) t = NFIELDS - 1;
+							if (t<s) diagl();
+							for(j = s; j <= t; j++) sel[j] = 1;
+							}
+						else sel[t] = (t > 0 ? 1 : 0);
+						r = s = t = 0;
+						if (c == '\0') {i--; break;}
+						continue;
+					default :
+						if (c< '0' || c> '9') diagl();
+						t = 10*t + c - '0';
+						continue;
+				}
+				for (j = t = 0; j < NFIELDS; j++) t += sel[j];
+				if (t == 0) diag("no fields\n");
+			} while (c != '\0');
+		}
+	}
+	--argc;
+	++argv;
+} /* end options */
+if (!(cflag || fflag)) diagl();
+
+--argc;
+filenr = 1;
+do {	/* for all input files */
+	if (argc > 0) inptr = fopen(argv[filenr], "r");
+	else inptr = stdin;
+  
+	if (inptr == NULL) {
+		write(2,"Cannot open :",14);
+		diag(argv[filenr]);
+	}
+	endflag = 0;
+	do {	/* for all lines of a file */
+		count = poscnt = backflag = 0;
+		p1 = &outbuf[0] - 1 ;
+		p2 = p1;
+		do { 	/* for all char of the line */
+			c = fgetc(inptr);
+			if (c == EOF) {
+				endflag = 1;
+				break;
+				}
+			if (count == NFIELDS - 1) diag("line too long\n");
+			if (c != '\n') *++p1 = c;
+			if (cflag && (c == BACKSPACE)) backflag++ ; else 
+				{ if ( !backflag ) poscnt += 1 ; else backflag-- ;}
+			if ( backflag > 1 ) diag("cannot handle multiple adjacent backspaces\n");
+			if ( ((c == '\n') && count > 0)  || c == del || cflag) {
+				count += 1;
+				if (fflag) poscnt = count  ;
+				if (sel[poscnt]) p2 = p1; else p1 = p2;
+			}
+		}while (c != '\n');
+		if ( !endflag && (count > 0 || !supflag)) {
+			if (*p1 == del) *p1 = '\0';
+				else *++p1 = '\0'; /*suppress trailing delimiter*/
+			puts(outbuf);
+			}
+	} while (!endflag) ;
+fclose(inptr);
+} while(++filenr <= argc);
+}
+
+diag(s)
+char *s;
+{
+	write(2, "cut : ", 6);
+	while(*s)
+		write(2,s++,1);
+	exit(2);
+}
+diagl()
+{
+diag("bad list for c/f option\n");
+}