UNIX — универсальная среда программирования

 #include <stdio.h>
 #define PERMS 0644 /* RW for owner, R for group, others */

 char *progname;

 main(argc, argv) /* cp: copy f1 to f2 */
  int argc;
  char *argv[];
 {
  char buf[BUFSIZ];

  progname = argv[0];
  if (argc != 3)
  error("Usage: %s from to", progname);
  if ((f1 = open(argv[1], 0)) == -1)
  error("can't open %s", argv[1]);
  if ((f2 = creat(argv[2] , PERMS)) == -1)
  error("can't create %s", argv[2]);
  while ((n = read(f1, buf, BUFSIZ)) > 0)
  if (write(f2, buf, n) != n)
  error("write error", (char*)0);
  exit(0);
 }
 #include "error.c"

3.8.15 doctype

 # doctype: synthesize proper command line for troff
 echo -n "cat $* | "
 egrep -h '^\.(EQ|TS|\[|PS|IS|PP)' $* |
 sort -u | awk '
 /^\.PP/ { ms++ }
 /^\.EQ/ { eqn++ }
 /^\.TS/ { tbl++ }
 /^\.PS/ { pic++ }
 /^\.IS/ { ideal++ }
 /^\.\[/ { refer++ }
 END {
  if (refer > 0) printf "refer | "
  if (pic > 0) printf "pic | "
  if (ideal > 0) printf "ideal | "
  if (tbl > 0) printf "tbl | "
  if (eqn > 0) printf "eqn | "
  printf "troff "
  if (ms > 0) printf "-ms"
  printf "\n"
 }'

3.8.16 double

 awk '
 FILENAME != prevfile { # new file
  NR = 1 # reset line number
  prevfile = FILENAME
 }
 NF > 0 {
  if ($1 == lastword)
  printf "double %s, file %s, line %d\n" ,$1,FILENAME,NR
  for (i = 2; i <= NF; i++)
  if ($i == $(i-1))
  printf "double %s, file %s, line %d\n" ,$i, FILENAME ,NR
  if (NF > 0)
  lastword = $NF
 }' $*

3.8.17 efopen.c

 FILE *efopen(file, mode) /* fopen file, die if can't */
  char *file, *mode;
 {
  FILE *fp, *fopen;
  extern char *progname;

  if ((fp = fopen(file, mode)) != NULL)
  return fp;
  fprintf (stderr, "%s: can't open file %s mode %s\n",
  progname, file, mode);
  exit(1);
 }

3.8.18 error.c

 error(s1, s2) /* print error message and die */
  char *s1, *s2;
 {
  extern int errno, sys_nerr;
  extern char *sys_errlist[], *progname;

  if (progname)
  fprintf(stderr, "%s: ", progname);
  fprintf(stderr, s1, s2);
  if (errno > 0 && errno < sys_nerr)
  fprintf (stderr, " (%s)", sys_errlist[errno]);
  fprintf(stderr, "\n");
  exit(1);
 }

3.8.19 field1

 awk '{ print $'$1' }'

3.8.20 field2

 awk "{ print \$$1 }"

3.8.21 fold

 # fold: fold long lines
 sed 's/\(->/ /g' $* | # convert tabs to spaces
 awk '
  BEGIN {
  N = 80 # folds at column 80
  for (i = 1; i <= N; i++) # make a string of blanks
  blanks = blanks " "
  }
  { if ((n = length($0)) <= N)
  print
  else {
  for (i = 1; n > N; n -= N) {
  printf "%s\\\n", substr($0, i ,N)
  i += N;
  }
  printf "%s%s\n", substr(blanks, 1, N-n), substr($0, i)
  }
  } '

3.8.22 frequent

 cat $* |
 tr -sc A-Za-z '\012' |
 sort |
 uniq -с |
 sort -n |
 tail |
 5

3.8.23 frequent2

 sed 's/[ \(->][ \(->]*/\
 /g' $* | sort | uniq -с | sort -nr | sed 10q

3.8.24 get

 # get: extract file from history

 PATH=/bin:/usr/bin

 VERSION=0
 while test "$1" != ""
 do
  case "$1" in