Mike Frysinger wrote:
> 	exec {mj_control_fd}<>${mj_control_pipe}

I'll have to remember that feature, but unfortunately it's new in bash 
4.1, so unless we're giving up 3.2 as the minimum for the tree....

> 	: $(( ++mj_num_jobs ))

Any reason not to do just

         (( ++mj_num_jobs ))

?

> 	: $(( --mj_num_jobs ))

> 		: $(( ret |= $? ))

Same.