/*exec函数示例*/
#include <stdio.h>
#include <unistd.h>

int main(void)
{
	int flag;
	pid_t pid;
	char *const argv[] = {"%U", "--user-data-dir=/home/Administrator/.chromiun", NULL};
	//exec把当前进程印象替换成新的程序文件，故调用进程被覆盖

	// 如果不指定全路径，则只检查PATH变量中存储的命令
	if((pid = fork())==0) {
		printf("in child process 1......\n");
		//flag = execvp("./hello", NULL);
		//envp变量的用
		char *envp[]={"PATH=.", NULL};
		flag = execve("hello", NULL, envp);
		if(flag == -1)
			printf("exec error!\n");
	}

	if((pid = fork())==0) {
		printf("in child process 2......\n");
		//执行ls命令
		flag = execlp("ls", "-al", NULL);
		if(flag == -1)
			printf("exec error!\n");
	}
	
	if((pid = fork())==0) {
		printf("in child process 3......\n");
		//启动chrome浏览器
		flag = execv("/usr/bin/chromium-browser", argv);
		if(flag == -1)
			printf("exec error!\n");
	}
	printf("in parent process ......\n");
	return 0;
}

#include <stdio.h>  
  
int main(void)  
{  
    printf("Hello world!\n");  
    return 0;  
}  

root@ubuntu:.../Linux_C/Process# ./exec_t  
in child process 1......  
in parent process ......  
in child process 3......  
root@ubuntu:.../Linux_C/Process# in child process 2......  
Hello world!  
exec_t    fifo_read.c   fork_1.c  hello.c    msg_send.c   signal_1.c  
exec_t.c  fifo_write.c  hello     msg_receive.c  semop_P_V.c