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

int main (int argc, char *argv[])
{
    FILE *f_in;
    char *cadena = "/etc/passwd";
    char login[100], passwd[100], gecos[100], gid[100], home[100], shell[100];
    int uid;
    
    if(argv[1])
        cadena = argv[1];
    
    f_in = fopen(cadena, "r");
    
    while(!feof(f_in)){
            if(fscanf(f_in,"%99[^:],%99[^:]%*c,%d,%99[^:]%*c,%99[^:],%99[^:]%*c,%99[^:]%*c\n",login,passwd,&uid, gid,gecos,home,shell))
            {
                printf("--- Fichero:\n");
                printf("Usuario: %s\n", login);
                printf("login: %s\n", gecos);
                printf("uid: %d\n",uid);
            }
    }
    return 0;
}