Can't find a module that is installed

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

Forks.pm is giving me problems with MAKER again, you'd think I would become a Perl coder instead of jsut a Perl user by now...

I tried running MAKER on a new cluster I installed it on and got the following response for every MPI process I created

Can't locate forks.pm in @INC (you may need to install the forks modul
+e) (@INC contains: /Data/Apps/maker/bin/../perl/lib /Data/Apps/maker/
+bin/../lib /Data/Apps/maker/bin/../src/inc/perl/lib /Data/Apps/CEGMA_
+v2.5/lib /etc/perl /usr/local/lib/x86_64-linux-gnu/perl/5.22.1 /usr/l
+ocal/share/perl/5.22.1 /usr/lib/x86_64-linux-gnu/perl5/5.22 /usr/shar
+e/perl5 /usr/lib/x86_64-linux-gnu/perl/5.22 /usr/share/perl/5.22 /usr
+/local/lib/site_perl /usr/lib/x86_64-linux-gnu/perl-base .) at /Data/
+Apps/maker/bin/maker line 42.
[download]

So I went looking

locate forks.pm
/home/seth/.cpan/build/forks-0.36-0/blib/lib/forks.pm
/home/seth/.cpan/build/forks-0.36-0/lib/forks.pm
/usr/local/lib/x86_64-linux-gnu/perl/5.22.1/forks.pm
[download]

Now, I might be crazy, but /usr/local/lib/x86_64-linux-gnu/perl/5.22.1 seems to be in both. Why can't it find forks.pm?

Comment on Can't find a module that is installed Select or Download Code

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Re: Can't find a module that is installed by stevieb (Canon) on Feb 16, 2017 at 18:52 UTC
Everything appears to be sane (less the mention of `Forks.pm` as opposed to `forks.pm` in the opening sentence, but that appears to be a simple typo). Can you post the output of `perl -v`? Also, does it still break if you do: `cp /usr/local/lib/x86_64-linux-gnu/perl/5.22.1/forks.pm . perl -E 'BEGIN{unshift @INC, ".";} use forks'` [download]	[reply] [d/l] [select]
Re^2: Can't find a module that is installed by Weebo (Novice) on Feb 16, 2017 at 19:53 UTC
Typing habits, I capitalize the first letter, so that should be forks.pm in the first line as well $ perl -v This is perl 5, version 22, subversion 1 (v5.22.1) built for x86_64-li +nux-gnu-thread-multi (with 58 registered patches, see perl -V for more detail) Copyright 1987-2015, Larry Wall Perl may be copied only under the terms of either the Artistic License + or the GNU General Public License, which may be found in the Perl 5 source ki +t. Complete documentation for Perl, including FAQ lists, should be found +on this system using "man perl" or "perldoc perl". If you have access to + the Internet, point your browser at http://www.perl.org/, the Perl Home Pa +ge. [download] I may be doing this part wrong; `$ cp /usr/local/lib/x86_64-linux-gnu/perl/5.22.1/forks . cp: omitting directory '/usr/local/lib/x86_64-linux-gnu/perl/5.22.1/fo +rks' $ perl -E 'BEGIN[unshift @INC, ".";} use forks' Illegal declaration of subroutine BEGIN at -e line 1.` [download] but the command for MAKER is `mpiexec -machinefile /Data/machinefile -n 4 maker maker_exe.ctl maker_opts.ctl maker_bopts.ctl` It doesn't explicitly call Perl	[reply] [d/l] [select]
Re^3: Can't find a module that is installed by RonW (Parson) on Feb 16, 2017 at 22:15 UTC
I may be doing this part wrong; `$ cp /usr/local/lib/x86_64-linux-gnu/perl/5.22.1/forks .` You did. The command should be: `cp /usr/local/lib/x86_64-linux-gnu/perl/5.22.1/forks.pm .` [download]	[reply] [d/l] [select]
Re^4: Can't find a module that is installed by stevieb (Canon) on Feb 16, 2017 at 22:19 UTC
Re^4: Can't find a module that is installed by Weebo (Novice) on Feb 17, 2017 at 16:15 UTC
Re^5: Can't find a module that is installed by poj (Abbot) on Feb 17, 2017 at 16:55 UTC
Some notes below your chosen depth have not been shown here
Re^5: Can't find a module that is installed by Anonymous Monk on Feb 17, 2017 at 22:25 UTC
Re^2: Can't find a module that is installed by Anonymous Monk on Feb 16, 2017 at 20:20 UTC
`perl -E 'BEGIN{unshift @INC, ".";} use forks' #gross #better perl -I. -e'use forks'` [download]	[reply] [d/l]
Re^3: Can't find a module that is installed by stevieb (Canon) on Feb 16, 2017 at 20:40 UTC
I wasn't sure if `-I` put the new directory at the beginning of `@INC` or appended it and was a bit pressed for time to go look at that moment ;) After a quick look at perlrun, it indeed does prepend.	[reply] [d/l] [select]
Re: Can't find a module that is installed by Weebo (Novice) on Feb 21, 2017 at 22:05 UTC
So I found the mistake. `Maker` is an MPI application, so I have a designated `machinefile`, well in this file the first entry was not the main node of the cluster. As such, `locate` was looking on node-1, while `maker` was looking on node-4. Checking node-4, it turns out `forks` was not installed. `CPAN` fixed that and now everything is working.	[reply] [d/l] [select]