#include<stdio.h>#include<sys/wait.h>#include<unistd.h>#include<sys/types.h>#include<stdlib.h>void mysys(char *str){pid_t pid;if(str==NULL){printf("Error:wrong shell string!\n");exit(0);}pid=fork();if(pid==0)execl("/bin/sh","sh","-c",str,NULL);wait(NULL);
}int main(){printf("---------------------------------\n");mysys("echo a b c d");printf("---------------------------------\n");mysys("ls /");printf("---------------------------------\n");return0;
}