GNU Parallel Bug Reports problem running most basic sem command

[Ghinwa Choueiter]

Hi,

I am running on an imac:

ProductName: Mac OS X

ProductVersion: 10.10.5

I brew install parallel 

and parallel --version gives

GNU parallel 20150822

Copyright (C) 2007,2008,2009,2010,2011,2012,2013,2014,2015 Ole Tange

and Free Software Foundation, Inc.

License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>

This is free software: you are free to change and redistribute it.

GNU parallel comes with no warranty.

Web site: http://www.gnu.org/software/parallel

When using programs that use GNU Parallel to process data for publication

please cite as described in 'parallel --bibtex'.

I am unable to run sem. Just the sem command with nothing else gives me:

parallel: Warning: Semaphore stuck for 30 seconds. Consider using --semaphoretimeout.

a lock file is being generated in ~/.parallel/semaphores

My activity monitor shows no cpu activity. 

What am I missing?

Thank you,

Ghinwa