How can I split and re-join STDOUT from multiple processes?

Question

I am working on a pipeline that has a few branch points that subsequently merge-- they look something like this:

         command2
        /        \\
command1           


        

Answer 1

Please see also https://unix.stackexchange.com/questions/28503/how-can-i-send-stdout-to-multiple-commands. Amongst all answers, I found this answer particularly fits my need.

Expand a little bit @Soren's answer,

$ ((date | tee >( wc >&3) | wc) 3>&1) | cat -n
     1         1       6      29
     2         1       6      29

You can do without using tee but an environment variable,

$ (z=$(date); (echo "$z"| wc ); (echo "$z"| wc) ) | cat -n
     1         1       6      29
     2         1       6      29

In my case, I applied this technique and wrote a much complex script that runs under busybox.