Annotation of src/usr.bin/head/head.c, Revision 1.10
1.10 ! millert 1: /* $OpenBSD: head.c,v 1.9 2002/03/14 16:44:24 mpech Exp $ */
1.2 deraadt 2:
1.1 deraadt 3: /*
4: * Copyright (c) 1980, 1987 Regents of the University of California.
5: * All rights reserved.
6: *
7: * Redistribution and use in source and binary forms, with or without
8: * modification, are permitted provided that the following conditions
9: * are met:
10: * 1. Redistributions of source code must retain the above copyright
11: * notice, this list of conditions and the following disclaimer.
12: * 2. Redistributions in binary form must reproduce the above copyright
13: * notice, this list of conditions and the following disclaimer in the
14: * documentation and/or other materials provided with the distribution.
1.10 ! millert 15: * 3. Neither the name of the University nor the names of its contributors
1.1 deraadt 16: * may be used to endorse or promote products derived from this software
17: * without specific prior written permission.
18: *
19: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29: * SUCH DAMAGE.
30: */
31:
32: #ifndef lint
33: char copyright[] =
34: "@(#) Copyright (c) 1980, 1987 Regents of the University of California.\n\
35: All rights reserved.\n";
36: #endif /* not lint */
37:
38: #ifndef lint
39: /*static char sccsid[] = "from: @(#)head.c 5.5 (Berkeley) 6/1/90";*/
1.10 ! millert 40: static char rcsid[] = "$OpenBSD: head.c,v 1.9 2002/03/14 16:44:24 mpech Exp $";
1.1 deraadt 41: #endif /* not lint */
42:
43: #include <stdio.h>
44: #include <stdlib.h>
45: #include <ctype.h>
1.4 aaron 46: #include <limits.h>
1.7 deraadt 47: #include <err.h>
1.4 aaron 48: #include <errno.h>
1.1 deraadt 49: #include <unistd.h>
50:
1.8 millert 51: static void usage(void);
1.1 deraadt 52:
53: /*
54: * head - give the first few lines of a stream or of each of a set of files
55: *
56: * Bill Joy UCB August 24, 1977
57: */
58:
59: int
60: main(argc, argv)
61: int argc;
62: char **argv;
63: {
1.9 mpech 64: long cnt;
1.4 aaron 65: int ch, firsttime;
66: long linecnt = 10;
67: char *inval = NULL, *p = NULL;
1.1 deraadt 68:
69: /* handle obsolete -number syntax */
70: if (argc > 1 && argv[1][0] == '-' && isdigit(argv[1][1])) {
1.4 aaron 71: linecnt = strtol((p = argv[1] + 1), &inval, 10);
1.1 deraadt 72: argc--; argv++;
73: }
74:
1.3 millert 75: while ((ch = getopt (argc, argv, "n:")) != -1)
1.1 deraadt 76: switch (ch) {
77: case 'n':
1.4 aaron 78: linecnt = strtol((p = optarg), &inval, 10);
1.1 deraadt 79: break;
80: default:
81: usage();
82: }
83: argc -= optind, argv += optind;
84:
1.4 aaron 85: if (p) {
86: if ((linecnt == LONG_MIN || linecnt == LONG_MAX) &&
87: errno == ERANGE)
1.5 aaron 88: err(1, "illegal line count -- %s", p);
1.4 aaron 89: else if (linecnt <= 0 || *inval)
1.5 aaron 90: errx(1, "illegal line count -- %s", p);
1.4 aaron 91: }
92:
1.1 deraadt 93: /* setlinebuf(stdout); */
94: for (firsttime = 1; ; firsttime = 0) {
95: if (!*argv) {
96: if (!firsttime)
97: exit(0);
98: }
99: else {
100: if (!freopen(*argv, "r", stdin)) {
1.5 aaron 101: warn("%s", *argv++);
1.4 aaron 102: continue;
1.1 deraadt 103: }
104: if (argc > 1) {
105: if (!firsttime)
106: putchar('\n');
107: printf("==> %s <==\n", *argv);
108: }
109: ++argv;
110: }
1.4 aaron 111: for (cnt = linecnt; cnt && !feof(stdin); --cnt)
1.1 deraadt 112: while ((ch = getchar()) != EOF)
113: if (putchar(ch) == '\n')
114: break;
115: }
116: /*NOTREACHED*/
117: }
118:
119:
120: static void
121: usage ()
122: {
123: fputs("usage: head [-n line_count] [file ...]\n", stderr);
124: exit(1);
125: }
126: