shell1.c

UNIX编程高级环境（第二版）的进程部分的程序源码

#include    <sys/types.h>
#include    <sys/wait.h>
#include    "ourhdr.h"

int
main(void)
{
    char    buf[MAXLINE];
    pid_t   pid;
    int     status;

    printf("%% ");    /* print prompt (printf requires %% to print %) */
    while (fgets(buf, MAXLINE, stdin) != NULL) {
        buf[strlen(buf) - 1] = 0;    /* replace newline with null */

        if ( (pid = fork()) < 0)
            err_sys("fork error");

        else if (pid == 0) {        /* child */
            execlp(buf, buf, (char *) 0);
            err_ret("couldn't execute: %s", buf);
            exit(127);
        }

        /* parent */
        if ( (pid = waitpid(pid, &status, 0)) < 0)
            err_sys("waitpid error");
        printf("%% ");
    }
    exit(0);
}