OS

 /* link.c */

#include <fcntl.h>
int main(int argc, char * argv[]) {
link(argv[1],argv[2]);
return 0;
}

/* mkdir.c */
#include <fcntl.h>
int main(int argc, char * argv[]) {
mkdir(argv[1],0700);
return 0;
}

/* unlink.c */
#include <fcntl.h>
int main(int argc, char * argv[]) {
unlink(argv[1]);
return 0;
}

/* myexec.c */ #include <stdio.h> main () { printf ("I'm process %d and I'm about to exec an ls -l\n",getpid ()); execl ("/bin/ls", "ls", "-l", NULL); /* Execute ls */ printf ("This line should never be executed\n"); }