UNIX — универсальная среда программирования - Керниган Брайан Уилсон

 int argc;

 char *argv[];

{

 struct stat buf;

 char *name, *getlogin();

 int lastsize = 0;

 progname = argv[0];

 if ((name = getlogin()) == NULL)

  error("can't get login name", (char*)0);

 if (chdir(maildir) == -1)

  error("can't cd to %s", maildir);

 for (;;) {

  if (stat(name, &buf) == -1) /* no mailbox */

   buf.st_size = 0;

  if (buf.st_size > lastsize)

   fprintf(stderr, "nYou have mail07n");

  lastsize = buf.st_size;

  sleep(60);

 }

}

#include "error.c"

3.8.13 checkmail.sh

# checkmail: watch mailbox for growth

PATH=/bin:/usr/bin

MAIL=/usr/spool/mail/`getname` # system dependent

t=${1-60}

x="`ls -l $MAIL`"

while :

do

 y="`ls -l $MAIL`"

 echo $x $y x="$y"

 sleep $t

done | awk '$4 < $12 { print "You have mail" }'

3.8.14 cp.c

/* cp: minimal version */

#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 %dn" ,$1,FILENAME,NR

 for (i = 2; i <= NF; i++)

  if ($i == $(i-1))

   printf "double %s, file %s, line %dn" ,$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)