问题：系统找不到环境变量
在终端输入:ls 后显示：
root@wei:/etc# ls
Command 'ls' is available in '/bin/ls'
The command could not be located because '/bin' is not included in the PATH environment variable.
ls: command not found
解决办法：
直接在终端输入：export PATH=/usr/bin:/bin
完成后则可以使用相关命令了。
