查看当前系统环境变量
cat test2:
#!/bin/bash # display user information from the system. echo "User info for userid:$USER" echo UID:$UID echo HOME:$HOME
添加执行权限：chmod u+x test2
运行：./test2 结果如下：
User info for userid:clarck UID:1000 HOME:/home/clarck
原文：http://www.cnblogs.com/tanlon/p/4027321.html