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/* $OpenBSD: head.c,v 1.3 1997/01/15 23:42:33 millert Exp $ */
/*
* Copyright (c) 1980, 1987 Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#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[] = "from: @(#)head.c 5.5 (Berkeley) 6/1/90";*/
static char rcsid[] = "$OpenBSD: head.c,v 1.3 1997/01/15 23:42:33 millert Exp $";
#endif /* not lint */
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <unistd.h>
static void usage ();
/*
* head - give the first few lines of a stream or of each of a set of files
*
* Bill Joy UCB August 24, 1977
*/
int
main(argc, argv)
int argc;
char **argv;
{
register int ch, cnt;
int firsttime, linecnt = 10;
/* handle obsolete -number syntax */
if (argc > 1 && argv[1][0] == '-' && isdigit(argv[1][1])) {
if ((linecnt = atoi(argv[1] + 1)) < 0) {
usage ();
}
argc--; argv++;
}
while ((ch = getopt (argc, argv, "n:")) != -1)
switch (ch) {
case 'n':
if ((linecnt = atoi(optarg)) < 0)
usage ();
break;
default:
usage();
}
argc -= optind, argv += optind;
/* setlinebuf(stdout); */
for (firsttime = 1; ; 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*/
}
static void
usage ()
{
fputs("usage: head [-n line_count] [file ...]\n", stderr);
exit(1);
}
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