Small sample program explaining how to use execl command

execl-example.c

#include<stdio.h>
#include<errno.h>
#include<stdlib.h>
#include<strings.h>
#include<unistd.h>

#define BASH_EXEC "/usr/bin/bash"
#define LS_EXEC "/usr/bin/ls"

#define BSIZE 50

int main(int argc, char* argv[]){

    if(argc < 2) {
	    //if we do not have path in our program arguments print help message and exit
	    printf("Usage: execl-example PATH \n eg. execl-example /usr/bin\n");
	    fflush(stdout);
	    return 0;
    }

    //this is a temp buffer used that will be used to build the argument
    char buffer[BSIZE];

    //get the buffer to be all NULLs
    bzero(buffer, BSIZE);

    //build the argument "ls -l /path/to/list/folders" and store it in buffer
    sprintf(buffer, "%s -l %s", LS_EXEC, argv[1]);
    //printf("buffer: %s\n", buffer);
    //build the argument vector

    //execute the command
    if(execl(BASH_EXEC, BASH_EXEC, "-c", buffer, NULL) < 0){
	    printf("Something terrible happended!");
	    return 1;
    }

    return 0;
}

Notes on compiling and running

$ gcc -g execl-example.c -o execl-example
$ ./execl-example /usr/bin