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/*
* 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[] =
"Usage: head [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";
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)
{
int i = 1;
char opt;
int len = 10;
/* 1st option is potentially special */
if ((argc > 1) && (argv[1][0] == '-') && isDecimal(argv[1][1])) {
int tmplen = atoi(&argv[1][1]);
if (tmplen) { len = tmplen; }
i = 2;
}
/* parse argv[] */
for ( ; i < argc; i++) {
if (argv[i][0] == '-') {
opt = argv[i][1];
switch (opt) {
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 1.4 1999/12/17 18:52:06 erik Exp $ */
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