菜鸟问题.

小小鸟4001

[root@linux scripts]# vi sh08-2.sh
#!/bin/bash
# Program:
#         Show "Hello" from $1.... by using case .... esac
# History:
# 2005/08/29        VBird        First release
PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin:~/bin
export PATH

case $1 in
  "hello")
        echo "Hello, how are you ?"
        ;;
  "")
        echo "You MUST input parameters, ex> $0 someword"
        ;;
  *)
        echo "Usage $0 {hello}" :D
        ;;
esac
在这个script中"ex> $0 someword"是什么意思?