On Sun, Aug 11, 2013 at 11:42 PM, Linda Walsh <[email protected]> wrote: > > Ole Tange wrote: >> >> On Sun, Aug 11, 2013 at 12:28 AM, Linda Walsh <[email protected]> wrote: : >> Personally I hate introducing an unneeded variable, so I would write it >> as: >> >> parallel gunzip ::: *gz > > specialized syntax -- didn't know...
Consider watching the intro videos https://www.youtube.com/playlist?list=PL284C9FF2488BC6D1 and reading the examples: http://www.gnu.org/software/parallel/man.html#example__working_as_xargs__n1__argument_appending Another good thing is that it does not use semaphores, so even if --semaphore (i.e sem) does not work on your system, the above may. It has the added benefit of only starting parallel once: The startup time of GNU Parallel is around 0.3 seconds which you would pay every time with --semaphore. >>> * The bugid: Can't open semaphore file >>> /home/law/.parallel/semaphores/id-2fdev2fcons1.lock: Permission denied >> >> Why is GNU Parallel not allowed to create >> /home/law/.parallel/semaphores/id-2fdev2fcons1.lock? : > While it is running (14 minutes and climbing), it seems to be testing > and recreating (if necessary) the semaphores directory under ".parallel". > I created my own dir, and it stayed, but if I removed the 'semaphores' > dir, it immediately re-created it... > It doesn't look like it is using real semaphores...but a file interlock > which might explain it running single threaded? When run in --semaphore mode GNU Parallel uses hard links to create a counting semaphore. If your filesystem does not support hard links the behaviour is undefined - and that is likely what you see. >> What OS is Perl running on and what file system is /home/law/.parallel >> hosted on? > > CYGWIN_NT-6.1-WOW64 / NTFS > > (thats 32bit cygwin on 64-bit win7-sp1)... I have no idea whether that configuration supports hard links or not. So it is possible that --semaphore does not work on your file system. /Ole
