execlp()

/* execlp.c */
#include <stdio.h>
#include <unistd.h>
int main(int argc,char *argv[])
{ 
    printf("Using *execlp* exec ls -l...\n");         
    execlp("ls","ls","-l",NULL); 
    printf("Program Terminated\n"); 
    return 0;
}

execlp() uses filename, argument list and original ENV to execute the program.

execlp("ls","ls","-l",NULL);

we only need to provide the name of the program, it will search accordingly in the locations specified in $PATH variable.

For the program arguments, they are included directly into execlp() functions.

Lastly, default environment variables in systm are used.