perl -V

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

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Re: perl -V by eXile (Priest) on Jul 31, 2004 at 17:15 UTC
Q1: AFAIK there are 2 ways of externally modifying @INC 1. PERL5LIB environment-variable 2. -I<directory-to-library> Q2: only the directories in @INC, and not subdirectories are searched for modules. Of course for the module Data::Dumper all directories in @INC would be searched for a subdirectory called 'Data', with a file called Dumper.pm.	[reply]
Re^2: perl -V by water (Deacon) on Jul 31, 2004 at 17:24 UTC
Many thanks. Is there a way to ask perl which directories in @INC are "built-ins" (from the build), vs. "user-added" (via -I or PERLLIB or PERL5LIB activity?)	[reply]
Re^3: perl -V by Aristotle (Chancellor) on Jul 31, 2004 at 19:49 UTC
Use the toolkit. `env -i perl -V` [download] Makeshifts last the longest.	[reply] [d/l]
Re: perl -V by hossman (Prior) on Jul 31, 2004 at 23:46 UTC
Different distrobutions compile in different lists of "default" library paths. Usually as a way of making sure that modules you install with CPAN don't overwrite/get overwritten by modules installed using the distrobutions own packaging system. If a directory is in your @INC because of the $ENV{PERL5LIB}, then it will also show up in the %ENV section just above @INC. I don't believe anything similar happens for directories added using -I `laptop:~> setenv PERL5LIB /perl5lib/env/var laptop:~> perl -V -I /dash/I \| tail -15 Built under linux Compiled at Apr 4 2004 05:57:53 %ENV: PERL5LIB="/perl5lib/env/var" @INC: /dash/I /perl5lib/env/var /usr/local/lib/perl/5.6.1 /usr/local/share/perl/5.6.1 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.6.1 /usr/share/perl/5.6.1 /usr/local/lib/site_perl .` [download] The Config module tells you all sorts of info on how your perl was built... `laptop:~> perl -l -MConfig -e'while(($k,$v)=each(%Config)) { print "$k +=$v" if $k =~ /lib/i or $v =~ /lib/i }' \| head archlibexp=/usr/lib/perl/5.6.1 installarchlib=/usr/lib/perl/5.6.1 installprivlib=/usr/share/perl/5.6.1 libpth=/usr/local/lib /lib /usr/lib libs=-lgdbm -ldb -ldl -lm -lc -lcrypt privlibexp=/usr/share/perl/5.6.1 archlib=/usr/lib/perl/5.6.1 config_arg11=-Dsitelib=/usr/local/share/perl/5.6.1 config_arg12=-Dsitearch=/usr/local/lib/perl/5.6.1 config_arg21=-Duseshrplib` [download]	[reply] [d/l] [select]
Re: perl -V by davidj (Priest) on Jul 31, 2004 at 17:22 UTC
As for Q1: check your PERL5LIB environmental variable (`echo $PERL5LIB`). (setting PERL5LIB is a way of including directories that are not normally part of @INC. It lets you customize your environment). You might find some of the directories listed there. You might also want to take a look at your start-up scripts. If they inherit other environments, they too may have PERL5LIB set. As for the `-I` flag. If it is followed by a list of directories, those directories will be added to the front of @INC for the execution of that script only. It is a way of specifying search directories for individual scripts. As for Q2: all subdirectories of the directories included in @INC will be searched. In other words, yes, `/usr/local/lib/site_perl/lib` will be searched. davidj update: I am wrong about my answer to Q2. eXile is right. Subdirectories will not be searched. Not sure what I was thinking there :)	[reply] [d/l] [select]
Re: perl -V by pbeckingham (Parson) on Jul 31, 2004 at 23:13 UTC
The ways I know of modifying @INC: `use lib 'path';` `push @INC, 'path'` `unshift @INC, 'path'` `#! /usr/bin/perl -Ipath` `$ENV{PERL5LIB}`	[reply] [d/l] [select]
Re: perl -V by water (Deacon) on Jul 31, 2004 at 17:35 UTC
I can't find where in the perl docs is says subdirs of @INC are searched automatically -- looked in perlmod, perlmodlib, and perlmodstyle. Are not-explicitly-named subdirs of @INC searched? (Of course `use Foo::Bar::Baz;` needs to go into Foo/Bar/ to get to Baz, but that to me is explicit. I mean, you can't just say `use Baz;` and expect perl to search down to find it, yes? So, unable to find docs, and getting confusing test results (likely other errors), logic would indicate subdirs of @INC aren't automatically searched. WOuld be delighted for someone authoritative to weigh in, or post a pointer to the docs where this is explained. (One reason I am confused is that the code I am looking at -- which itself may not be correct, that's another issue -- seems to rely on the fact that `/usr/local/lib/site_perl/lib` [download] is part of @INC, where (I think) only `/usr/local/lib/site_perl` [download] is.) Confused I am.	[reply] [d/l] [select]