Calling a perl script from GNU Parallel

stevee has asked for the wisdom of the Perl Monks concerning the following question:

Greetings oh wise and venerable monks!

I need to be able to call a perl script on a number of servers (two in my test set-up) using GNU parallel that "does something" and returns the results through STDIN to the calling terminal. I have quite happily managed a form of command line distributed grep as thus

parallel -q --onall --sshloginfile mycomputers --tag grep -H -E '3864885157' ::: /home/stephen/TO174/Data/dgrep-test/*.txt

Now I want to run a perl script on the servers listed in the loginfile "mycomputers". I have tried

parallel -q -onall -sshloginfile mycomputers --tag ./test.pl

and a number of variations but I always get the error message about

parallel: Input is read from the terminal. Only experts do this on purpose. Press CTRL-D to exit.

I have looked at all the examples but nothing I try seems to work. Can anyone give me a hint, or the answer as it is late here and I have been on this screen since 0600 today!

Many thanks

Steve

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Re: Calling a perl script from GNU Parallel by kcott (Archbishop) on Jul 10, 2012 at 19:16 UTC
I'm not a `parallel` user but here's some suggestions for things to check (a few are very basic but I don't know what you've tried): Is `./test.pl` executable? Does `./test.pl` have a shebang line that is incompatible with your target servers? Is `./test.pl` trying to read from stdin? Does `./test.pl` run without errors or warnings if `use strict;` and `use warnings;` are used? Does calling `parallel ... perl ./test.pl` work any better? If none of that helps, please post the `./test.pl` code. -- Ken	[reply] [d/l] [select]
Re^2: Calling a perl script from GNU Parallel by stevee (Acolyte) on Jul 12, 2012 at 09:28 UTC
Ken et al Thanks for the suggestions: the script is executable and has a compatible shebang, it runs successfully on both machines using strict. The original script is not trying to read from STDIN, so I can get away without passing arguments with parallel The suggested syntax does not work either unfortunately The test script is purely so I can get parallel working in the first instance so it just prints "Hello world\n"! Kind regards Stephen	[reply]
Re: Calling a perl script from GNU Parallel by zentara (Archbishop) on Jul 10, 2012 at 19:25 UTC
Have you seen this bug report? bug report It has some debugging tips. I'm not really a human, but I play one on earth. Old Perl Programmer Haiku ................... flash japh	[reply]
Re^2: Calling a perl script from GNU Parallel by stevee (Acolyte) on Jul 12, 2012 at 09:33 UTC
Interesting bug report, but seems to garner a number of contradictory answers. I tried the --gnu switch but it unfortunately did not help! Thanks Steve	[reply]
Re: Calling a perl script from GNU Parallel by bennymack (Pilgrim) on Sep 21, 2012 at 12:35 UTC
I believe you're looking for '--nonall' instead of '--onall'. The former needs no arguments where the latter wants an argument list. Try this: `parallel -q --nonall --sshloginfile mycomputers --tag ./test.pl` [download]	[reply] [d/l]
Re: Calling a perl script from GNU Parallel by Anonymous Monk on Jul 11, 2012 at 00:00 UTC
Hi, Is test.pl on the remote machines? In the correct directory? J.C.	[reply]


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