76 lines
1.6 KiB
C
76 lines
1.6 KiB
C
#define _GNU_SOURCE
|
|
#include <stdint.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <unistd.h>
|
|
|
|
// You may assume that lines are no longer than 1024 bytes
|
|
#define LINELEN 1024
|
|
|
|
static void usage (void);
|
|
|
|
int
|
|
main (int argc, char *argv[])
|
|
{
|
|
int opt;
|
|
char *delimitter = " ";
|
|
long field = 1;
|
|
|
|
while ((opt = getopt (argc, argv, "d:f:")) != -1)
|
|
{
|
|
switch (opt)
|
|
{
|
|
case 'd':
|
|
delimitter = optarg;
|
|
break;
|
|
case 'f':
|
|
field = strtol (optarg, NULL, 10);
|
|
break;
|
|
default:
|
|
printf ("./bin/cut: invalid option -- \'%c\'\n", optopt);
|
|
exit (EXIT_FAILURE);
|
|
}
|
|
}
|
|
|
|
if (field < 1)
|
|
{
|
|
usage ();
|
|
exit (EXIT_FAILURE);
|
|
}
|
|
|
|
FILE *file = optind < argc ? fopen (argv[optind], "r") : stdin;
|
|
if (file == NULL)
|
|
{
|
|
perror ("Failed to open input file");
|
|
exit (EXIT_FAILURE);
|
|
}
|
|
|
|
char buffer[LINELEN];
|
|
|
|
while (fgets (buffer, sizeof (buffer), file) != NULL)
|
|
{
|
|
buffer[strcspn (buffer, "\n")] = '\0';
|
|
|
|
char *token = strtok (buffer, delimitter);
|
|
long i = 1;
|
|
while (i++ < field) token = strtok (NULL, delimitter);
|
|
|
|
printf("%s\n", token != NULL ? token : "");
|
|
}
|
|
|
|
return EXIT_SUCCESS;
|
|
}
|
|
|
|
static void
|
|
usage (void)
|
|
{
|
|
printf ("cut, splits each line based on a delimiter\n");
|
|
printf ("usage: cut [FLAG] FILE\n");
|
|
printf ("FLAG can be:\n");
|
|
printf (
|
|
" -d C split each line based on the character C (default ' ')\n");
|
|
printf (" -f N print the Nth field (1 is first, default 1)\n");
|
|
printf ("If no FILE specified, read from STDIN\n");
|
|
}
|