如何记录管道符左边命令的退出码?

问题描述：

有脚本如下:
1: make all | tee log
2: ???? # How to get the exit code of command 'make'?  

由于在编译的时候想看到编译进度，所以这里用了 tee， 而没用重定向。
在第二行代码处，想知道make是否成功了。
不知该如何实现？

解决方案：

To know the exit status of the elements of a pipeline
    cmd1 | cmd2 | cmd3
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}.