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