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
35 static const char copyright[] =
36 "@(#) Copyright (c) 1980, 1987, 1992, 1993\n\
37 The Regents of the University of California. All rights reserved.\n";
42 static char sccsid[] = "@(#)head.c 8.2 (Berkeley) 5/4/95";
44 static const char rcsid[] =
48 #include <sys/types.h>
58 * head - give the first few lines of a stream or of each of a set of files
60 * Bill Joy UCB August 24, 1977
63 void head __P((FILE *, int));
64 void head_bytes __P((FILE *, int));
65 void obsolete __P((char *[]));
66 void usage __P((void));
77 int first, linecnt = -1, bytecnt = -1;
81 while ((ch = getopt(argc, argv, "n:c:")) != -1)
84 bytecnt = strtol(optarg, &ep, 10);
85 if (*ep || bytecnt <= 0)
86 errx(1, "illegal byte count -- %s", optarg);
89 linecnt = strtol(optarg, &ep, 10);
90 if (*ep || linecnt <= 0)
91 errx(1, "illegal line count -- %s", optarg);
100 if (linecnt != -1 && bytecnt != -1)
101 errx(1, "can't combine line and byte counts");
105 for (first = 1; *argv; ++argv) {
106 if ((fp = fopen(*argv, "r")) == NULL) {
112 (void)printf("%s==> %s <==\n",
113 first ? "" : "\n", *argv);
119 head_bytes(fp, bytecnt);
123 else if (bytecnt == -1)
124 head(stdin, linecnt);
126 head_bytes(stdin, bytecnt);
138 while (cnt && (ch = getc(fp)) != EOF) {
139 if (putchar(ch) == EOF)
152 register int readlen;
155 if (cnt < sizeof(buf))
158 readlen = sizeof(buf);
159 readlen = fread(buf, sizeof(char), readlen, fp);
162 if (fwrite(buf, sizeof(char), readlen, stdout) != readlen)
174 while ((ap = *++argv)) {
175 /* Return if "--" or not "-[0-9]*". */
176 if (ap[0] != '-' || ap[1] == '-' || !isdigit(ap[1]))
178 if ((ap = malloc(strlen(*argv) + 2)) == NULL)
182 (void)strcpy(ap + 2, *argv + 1);
190 (void)fprintf(stderr, "usage: head [-n lines] [-c bytes] [file ...]\n");