C PROGRAMMING

A simple shell (command interpreter)

#define TRUE 1!

/* declare cmd, params, envp, stat, prompt, readcmd */!

!

while (TRUE) { ! !!!/* repeat forever */!

!prompt(); ! !!!!/* display prompt */

!readcmd(cmd, params); /* read input from terminal*/!

!if (fork() != 0) {! !/* fork child process */!

! !/* parent code */!

! !waitpid(

-

1, &stat, 0); ! !/* wait for child */!

!} else {!

! !/* child code */!

! !execve(cmd, params, envp);!/* execute command */!

!}!

}!