GetOpt Example

getopts.c

#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

    int
main (int argc, char **argv)
{
    int verbose = 0;
    int help = 0;
    char *file = NULL;
    int index;
    int c;

    opterr = 0;

    while ((c = getopt (argc, argv, "vhf:")) != -1)
        switch (c)
        {
            case 'v':
                verbose = 1;
                break;
            case 'f':
                file = optarg;
                break;
            case 'h':
                help = 1;
                printf("Options:\n");
                printf("-h Print this message\n");
                printf("-v Verbose output\n");
                printf("-f <filename> (Required) Filename to send output\n");
                return 0;
            case '?':
                if (optopt == 'f')
                    fprintf (stderr, "Option -%c requires an argument.\n", optopt);
                else if (isprint (optopt))
                    fprintf (stderr, "Unknown option `-%c'.\n", optopt);
                else
                    fprintf (stderr,
                            "Unknown option character `\\x%x'.\n",
                            optopt);
                return 1;
            default:
                abort ();
        }

    printf ("verbose = %d, file = %s, help = %d\n",
            verbose, file, help);

    for (index = optind; index < argc; index++)
        printf ("Non-option argument %s\n", argv[index]);
    return 0;
}