sbase/head.c

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C
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/* See LICENSE file for copyright and license details. */
#include <stdio.h>
#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
#include "util.h"
static void head(FILE *, const char *, long);
int
main(int argc, char *argv[])
{
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char c;
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long n = 10;
FILE *fp;
while((c = getopt(argc, argv, "n:")) != -1)
switch(c) {
case 'n':
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n = strnum(optarg, 0);
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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];
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long i = 0;
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while(i < n && fgets(buf, sizeof buf, fp)) {
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fputs(buf, stdout);
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if(buf[strlen(buf)-1] == '\n')
i++;
}
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if(ferror(fp))
eprintf("%s: read error:", str);
}