sbase/head.c

48 lines
914 B
C

/* See LICENSE file for copyright and license details. */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include "util.h"
static void head(FILE *, const char *, long);
int
main(int argc, char *argv[])
{
char *end, c;
long n = 10;
FILE *fp;
while((c = getopt(argc, argv, "n:")) != -1)
switch(c) {
case 'n':
n = strtol(optarg, &end, 0);
if(*end != '\0')
eprintf("%s: not a number\n", optarg);
break;
default:
exit(EXIT_FAILURE);
}
if(optind == argc)
head(stdin, "<stdin>", n);
else for(; optind < argc; optind++) {
if(!(fp = fopen(argv[optind], "r")))
eprintf("fopen %s:", argv[optind]);
head(fp, argv[optind], n);
fclose(fp);
}
return EXIT_SUCCESS;
}
void
head(FILE *fp, const char *str, long n)
{
char buf[BUFSIZ];
int i;
for(i = 0; i < n && fgets(buf, sizeof buf, fp); i++)
fputs(buf, stdout);
if(ferror(fp))
eprintf("%s: read error:", str);
}