日常问题2011

本文档用于记录日常遇到的问题，因为比较零散，不便于分类，在此记录，便于查询。

201105

1. 如何记录管道符左边命令的退出码？

The exit codes are provided in the PIPESTATUS special array.cmd1 exit code is in ${PIPESTATUS[0]}, cmd3 exit code in ${PIPESTATUS[2]}, so that $? is always the same as ${PIPESTATUS: -1}.