http://wiki.ubuntu.org.cn/Shell%E7%BC%96%E7%A8%8B%E5%9F%BA%E7%A1%80
http://scc.qibebt.cas.cn/docs/linux/script/Shell%20%B1%E0%B3%CC.pdf
http://wiki.ubuntu.org.cn/Shell%E7%BC%96%E7%A8%8B%E5%9F%BA%E7%A1%80
http://scc.qibebt.cas.cn/docs/linux/script/Shell%20%B1%E0%B3%CC.pdf