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 * 4. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 static const char copyright
[] =
32 "@(#) Copyright (c) 1980, 1987, 1992, 1993\n\
33 The Regents of the University of California. All rights reserved.\n";
38 static char sccsid
[] = "@(#)head.c 8.2 (Berkeley) 5/4/95";
41 #include <sys/cdefs.h>
42 __FBSDID("$FreeBSD$");
44 #include <sys/types.h>
55 * head - give the first few lines of a stream or of each of a set of files
57 * Bill Joy UCB August 24, 1977
60 static void head(FILE *, int);
61 static void head_bytes(FILE *, off_t
);
62 static void obsolete(char *[]);
63 static void usage(void);
66 main(int argc
, char *argv
[])
70 int first
, linecnt
= -1, eval
= 0;
75 while ((ch
= getopt(argc
, argv
, "n:c:")) != -1)
78 bytecnt
= strtoimax(optarg
, &ep
, 10);
79 if (*ep
|| bytecnt
<= 0)
80 errx(1, "illegal byte count -- %s", optarg
);
83 linecnt
= strtol(optarg
, &ep
, 10);
84 if (*ep
|| linecnt
<= 0)
85 errx(1, "illegal line count -- %s", optarg
);
94 if (linecnt
!= -1 && bytecnt
!= -1)
95 errx(1, "can't combine line and byte counts");
99 for (first
= 1; *argv
; ++argv
) {
100 if ((fp
= fopen(*argv
, "r")) == NULL
) {
106 (void)printf("%s==> %s <==\n",
107 first
? "" : "\n", *argv
);
113 head_bytes(fp
, bytecnt
);
116 } else if (bytecnt
== -1)
117 head(stdin
, linecnt
);
119 head_bytes(stdin
, bytecnt
);
125 head(FILE *fp
, int cnt
)
128 size_t error
, readlen
;
130 while (cnt
&& (cp
= fgetln(fp
, &readlen
)) != NULL
) {
131 error
= fwrite(cp
, sizeof(char), readlen
, stdout
);
132 if (error
!= readlen
)
139 head_bytes(FILE *fp
, off_t cnt
)
145 if ((uintmax_t)cnt
< sizeof(buf
))
148 readlen
= sizeof(buf
);
149 readlen
= fread(buf
, sizeof(char), readlen
, fp
);
152 if (fwrite(buf
, sizeof(char), readlen
, stdout
) != readlen
)
159 obsolete(char *argv
[])
163 while ((ap
= *++argv
)) {
164 /* Return if "--" or not "-[0-9]*". */
165 if (ap
[0] != '-' || ap
[1] == '-' || !isdigit(ap
[1]))
167 if ((ap
= malloc(strlen(*argv
) + 2)) == NULL
)
171 (void)strcpy(ap
+ 2, *argv
+ 1);
180 (void)fprintf(stderr
, "usage: head [-n lines | -c bytes] [file ...]\n");