2 * Copyright (c) 1980, 1987, 1992, 1993
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * @(#) Copyright (c) 1980, 1987, 1992, 1993 The Regents of the University of California. All rights reserved.
34 * @(#)head.c 8.2 (Berkeley) 5/4/95
35 * $FreeBSD: src/usr.bin/head/head.c,v 1.10.2.1 2002/02/16 12:29:04 dwmalone Exp $
36 * $DragonFly: src/usr.bin/head/head.c,v 1.6 2008/06/05 18:06:33 swildner Exp $
47 * head - give the first few lines of a stream or of each of a set of files
49 * Bill Joy UCB August 24, 1977
52 static void head(FILE *, size_t);
53 static void head_bytes(FILE *, size_t);
54 static void obsolete(char *[]);
55 static void usage(void);
58 main(int argc, char **argv)
62 int first, linecnt = -1, bytecnt = -1, eval = 0;
66 while ((ch = getopt(argc, argv, "n:c:")) != -1)
69 bytecnt = strtol(optarg, &ep, 10);
70 if (*ep != 0 || bytecnt <= 0)
71 errx(1, "illegal byte count -- %s", optarg);
74 linecnt = strtol(optarg, &ep, 10);
75 if (*ep != 0 || linecnt <= 0)
76 errx(1, "illegal line count -- %s", optarg);
84 if (linecnt != -1 && bytecnt != -1)
85 errx(1, "can't combine line and byte counts");
89 for (first = 1; *argv; ++argv) {
90 if ((fp = fopen(*argv, "r")) == NULL) {
96 printf("%s==> %s <==\n",
97 first ? "" : "\n", *argv);
103 head_bytes(fp, bytecnt);
106 } else if (bytecnt == -1)
107 head(stdin, linecnt);
109 head_bytes(stdin, bytecnt);
115 head(FILE *fp, size_t cnt)
118 size_t error, readlen;
120 while (cnt && (cp = fgetln(fp, &readlen)) != NULL) {
121 error = fwrite(cp, sizeof(char), readlen, stdout);
122 if (error != readlen)
129 head_bytes(FILE *fp, size_t cnt)
135 if (cnt < sizeof(buf))
138 readlen = sizeof(buf);
139 readlen = fread(buf, sizeof(char), readlen, fp);
142 if (fwrite(buf, sizeof(char), readlen, stdout) != readlen)
149 obsolete(char **argv)
153 while ((ap = *++argv)) {
154 /* Return if "--" or not "-[0-9]*". */
155 if (ap[0] != '-' || ap[1] == '-' || !isdigit(ap[1]))
157 if ((ap = malloc(strlen(*argv) + 2)) == NULL)
158 err(1, "malloc failed");
161 strcpy(ap + 2, *argv + 1);
169 fprintf(stderr, "usage: head [-n lines | -c bytes] [file ...]\n");