122 lines
3.4 KiB
C
122 lines
3.4 KiB
C
/* $NetBSD: head.c,v 1.6 1997/01/09 20:19:50 tls Exp $ */
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/*
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* Copyright (c) 1980, 1987 Regents of the University of California.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef lint
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char copyright[] =
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"@(#) Copyright (c) 1980, 1987 Regents of the University of California.\n\
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All rights reserved.\n";
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#endif /* not lint */
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#ifndef lint
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/*static char sccsid[] = "from: @(#)head.c 5.5 (Berkeley) 6/1/90";*/
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static char rcsid[] = "$NetBSD: head.c,v 1.6 1997/01/09 20:19:50 tls Exp $";
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#endif /* not lint */
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#include <stdio.h>
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#include <stdlib.h>
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#include <ctype.h>
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#include <unistd.h>
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static void usage ();
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/*
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* head - give the first few lines of a stream or of each of a set of files
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*
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* Bill Joy UCB August 24, 1977
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*/
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int
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main(argc, argv)
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int argc;
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char **argv;
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{
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register int ch, cnt;
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int firsttime, linecnt = 10;
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/* handle obsolete -number syntax */
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if (argc > 1 && argv[1][0] == '-' && isdigit(argv[1][1])) {
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if ((linecnt = atoi(argv[1] + 1)) < 0) {
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usage ();
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}
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argc--; argv++;
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}
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while ((ch = getopt (argc, argv, "n:")) != EOF)
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switch (ch) {
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case 'n':
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if ((linecnt = atoi(optarg)) < 0)
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usage ();
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break;
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default:
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usage();
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}
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argc -= optind, argv += optind;
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/* setlinebuf(stdout); */
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for (firsttime = 1; ; firsttime = 0) {
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if (!*argv) {
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if (!firsttime)
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exit(0);
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}
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else {
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if (!freopen(*argv, "r", stdin)) {
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fprintf(stderr, "head: can't read %s.\n", *argv);
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exit(1);
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}
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if (argc > 1) {
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if (!firsttime)
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putchar('\n');
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printf("==> %s <==\n", *argv);
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}
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++argv;
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}
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for (cnt = linecnt; cnt; --cnt)
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while ((ch = getchar()) != EOF)
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if (putchar(ch) == '\n')
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break;
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}
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/*NOTREACHED*/
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}
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static void
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usage ()
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{
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fputs("usage: head [-n line_count] [file ...]\n", stderr);
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exit(1);
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}
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