cis-lclient06:~/class/nov22>more exec4.c
#include <syscall.h>
#include <unistd.h>
#include <stdio.h>
int main(void) {
    execl("/bin/ls", "ls", (char *) NULL);
    printf("Only get here if execl() fails\n");
}

cis-lclient06:~/class/nov22>gcc exec4.c
cis-lclient06:~/class/nov22>./a.out
a.out    bsh.c     exec1.c  exec3.c  exec5.c  exec6.c  exec8.c  forkexec.c  little2.c    one
bobsh.c  exec10.c  exec2.c  exec4.c  exec6    exec7.c  exec9.c  little1.c   myinclude.h  one.c
cis-lclient06:~/class/nov22>