Call UNIX crypt function from command line. Compile using: $gcc crypt.c -lcrypt -o crypt

crypt.c

#include <stdio.h>
#include <unistd.h>
#include <crypt.h>

int main(int argc, char **argv) {
    int option;
    int debug = 0;

    const char *salt;
    const char *pass;
 
    while ((option = getopt(argc, argv, "p:s:d")) != -1) {
        switch (option) {
            case 'p':
                pass = optarg;
                break;
            case 's':
                salt = optarg;
                break;
            case 'd':
                debug = 1;
                break;
            default:
                fprintf(stderr, "unknown parameter\n");
                return 1;
        }
    }
 
    if (pass == NULL) {
        fprintf(stderr, "password not specified\n");
        return 1;
    }
    if (salt == NULL) {
        fprintf(stderr, "salt not specified\n");
        return 1;
    }

    if (debug) {
        fprintf(stdout, "password:%s\nsalt:%s\n\n", pass, salt);
    }
 
    const char *out = crypt(pass, salt);

    if (out != NULL) {
        fprintf(stdout, "%s\n", out);
    } else {
        fprintf(stderr, "computation failed\n");
    }
 
    return 0;
}