new copyright notice

[unix-history] / usr / src / usr.bin / head / head.c

/*
* Copyright (c) 1980, 1987 Regents of the University of California.
* All rights reserved.
*
* %sccs.include.redist.c%
*/

#ifndef lint
char copyright[] =
"@(#) Copyright (c) 1980, 1987 Regents of the University of California.\n\
All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char sccsid[] = "@(#)head.c      5.5 (Berkeley) %G%";
#endif /* not lint */

#include <stdio.h>
#include <ctype.h>
/*
* head - give the first few lines of a stream or of each of a set of files
*
* Bill Joy UCB August 24, 1977
*/

main(argc, argv)
       int     argc;
       char    **argv;
{
       register int    ch, cnt;
       int     firsttime, linecnt = 10;

       if (argc > 1 && argv[1][0] == '-') {
               if (!isdigit(argv[1][1])) {
                       fprintf(stderr, "head: illegal option -- %c\n", argv[1][1]);
                       goto usage;
               }
               if ((linecnt = atoi(argv[1] + 1)) < 0) {
usage:                  fputs("usage: head [-line_count] [file ...]\n", stderr);
                       exit(1);
               }
               --argc; ++argv;
       }
       /* setlinebuf(stdout); */
       for (firsttime = 1, --argc, ++argv;; firsttime = 0) {
               if (!*argv) {
                       if (!firsttime)
                               exit(0);
               }
               else {
                       if (!freopen(*argv, "r", stdin)) {
                               fprintf(stderr, "head: can't read %s.\n", *argv);
                               exit(1);
                       }
                       if (argc > 1) {
                               if (!firsttime)
                                       putchar('\n');
                               printf("==> %s <==\n", *argv);
                       }
                       ++argv;
               }
               for (cnt = linecnt; cnt; --cnt)
                       while ((ch = getchar()) != EOF)
                               if (putchar(ch) == '\n')
                                       break;
       }
       /*NOTREACHED*/
}