#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <errno.h>
 
void main(int argc, char *argv[])    
                // argc=#of parameters  
                // argv=array of strings for each parameter
{
int status;
char *prog = argv[0];
                // first argv string is the program name
                // load prog with the pointer to that string
 
char *new_cmd = "/bin/echo";
                // the command to be executed by the O/S
 
char *cmd_args[] = {"echo", "hello", "world", NULL};
                // an array of strings containing the arguments 
                // to the /bin/echo command:
                //          bin/echo  echo hello world
 
char *cmd_env[] = {NULL};
                // there are no environment parameters needed
 
status = execve(new_cmd, cmd_args, cmd_env);
                // execute the ECHO command with the parameters
 
/*
* execve does not return unless there is an error.
*/
 
fprintf(stderr, "%s: ", prog);  // output the program name
perror("execve");               // output the error status from the call
exit(1);
}

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <errno.h>
 
void
main(int argc, char *argv[])
{
int status;
char *prog = argv[0]; /* this is what you type to start THIS program (e.g. './a.out') */
char *new_cmd = "/bin/echo"; /* the command that you would like to execute */
char *cmd_args[] = {"echo", "hello", "world", NULL}; /* arguments to pass to the command Note that you must repeat the name of the program, as this is argv[0] */
char *cmd_env[] = {NULL};
status = execve(new_cmd, cmd_args, cmd_env); /* this will execute the program defined above. Note that you pass to it the location of the command, new_cmd, the arguments, cmd_args, and cmd_env, which is NULL */
/*
* Because you did not start another process to run this program, this program is replaced in memory with the program defined above in execve. Should that fail, then this program will continue below. Basically, if the program works correctly, you will never make it down here.
*/
fprintf(stderr, "%s: ", prog);
perror("execve");
exit(1);
}