Linux Shell简介
http://www.linuxsir.org/main/?q=node/135
Linux下的命令解释器 ash
http://my.chinaunix.net/space.php?uid=13891171&do=blog&id=136016
浅析busybox-1.12.0中ash的脚本命令局限性
http://blog.chinaunix.net/space.php?uid=20564848&do=blog&cuid=1745642
Ash (Almquist Shell) Variants,ash各个变种的详细信息
http://www.in-ulm.de/~mascheck/various/ash/
the Bourne Shell参考
http://www.grymoire.com/Unix/Sh.html
Bourne Shell Programming
http://www.ooblick.com/text/sh/
Bourne Shell Scripting/Appendix C: Quick Reference
http://en.wikibooks.org/wiki/Bourne_Shell_Scripting/Appendix_C:_Quick_Reference
http://www.cnblogs.com/gudai/archive/2006/07/13/450246.html
Almquist shell(ash)