I've been using CommandShell for some operations on OSX with Pharo5. After doing a number of "PipeableOSProcess command:" calls (~150), I get an error inside ExternalPipe:makePipe. For my purposes, I can get around this by restarting Pharo and limiting the number of operations each session. But, it is an indication that some resource is not getting freed when the PipeableOSProcess is deleted (garbage collected). I just thought I'd mention the bug.
Cheers,
Jeff