听起来比较别口：
直接看代码：
shell如下：
[root@sevck_linux ~]# </etc/passwd grep root root:x:0:0:root:/root:/bin/bash operator:x:11:0:operator:/root:/sbin/nologin [root@sevck_linux ~]# cat /etc/passwd | grep root root:x:0:0:root:/root:/bin/bash operator:x:11:0:operator:/root:/sbin/nologin [root@sevck_linux ~]# < <(echo this is a test) wc 1 4 15 [root@sevck_linux ~]# echo this is a test | wc 1 4 15 [root@sevck_linux ~]#
just do it .
原文：http://www.cnblogs.com/sevck/p/7256051.html