1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
|
/*
* Mini head implementation for busybox
*
*
* Copyright (C) 1999 by Lineo, inc.
* Written by John Beppu <beppu@lineo.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include "internal.h"
#include <errno.h>
#include <stdio.h>
const char head_usage[] =
"head [OPTION] [FILE]...\n\n"
"Print first 10 lines of each FILE to standard output.\n"
"With more than one FILE, precede each with a header giving the\n"
"file name. With no FILE, or when FILE is -, read standard input.\n\n"
"Options:\n"
"\t-n NUM\t\tPrint first NUM lines instead of first 10\n";
int
head(int len, FILE *src)
{
int i;
char buffer[1024];
for (i = 0; i < len; i++) {
fgets(buffer, 1024, src);
if (feof(src)) { break; }
fputs(buffer, stdout);
}
return 0;
}
/* BusyBoxed head(1) */
int
head_main(int argc, char **argv)
{
char opt;
int len = 10, tmplen, i;
/* parse argv[] */
for (i = 1; i < argc; i++) {
if (argv[i][0] == '-') {
opt = argv[i][1];
switch (opt) {
case 'n':
tmplen = 0;
if (i++ < argc)
tmplen = atoi(argv[i]);
if (tmplen < 1)
usage(head_usage);
len = tmplen;
break;
case '-':
case 'h':
usage(head_usage);
default:
fprintf(stderr, "head: invalid option -- %c\n", opt);
usage(head_usage);
}
} else {
break;
}
}
/* get rest of argv[] or stdin if nothing's left */
if (i >= argc) {
head(len, stdin);
} else {
int need_headers = ((argc - i) > 1);
for ( ; i < argc; i++) {
FILE *src;
src = fopen(argv[i], "r");
if (!src) {
fprintf(stderr,"head: %s: %s\n", argv[i], strerror(errno));
} else {
/* emulating GNU behaviour */
if (need_headers) {
fprintf(stdout, "==> %s <==\n", argv[i]);
}
head(len, src);
if (i < argc - 1) {
fprintf(stdout, "\n");
}
}
}
}
exit(0);
}
/* $Id: head.c,v 1.5 2000/01/23 18:19:02 erik Exp $ */
|
