pmload - show what files a given module loads at compile time
Given an argument of a module name, show all the files that are loaded directly or indirectly when the module is used at compile-time.
$ pmload IO::Handle /usr/local/devperl/lib/5.00554/Exporter.pm /usr/local/devperl/lib/5.00554/Carp.pm /usr/local/devperl/lib/5.00554/strict.pm /usr/local/devperl/lib/5.00554/vars.pm /usr/local/devperl/lib/5.00554/i686-linux/DynaLoader.pm /usr/local/devperl/lib/5.00554/i686-linux/IO/Handle.pm /usr/local/devperl/lib/5.00554/Symbol.pm /usr/local/devperl/lib/5.00554/i686-linux/IO/File.pm /usr/local/devperl/lib/5.00554/SelectSaver.pm /usr/local/devperl/lib/5.00554/i686-linux/Fcntl.pm /usr/local/devperl/lib/5.00554/AutoLoader.pm /usr/local/devperl/lib/5.00554/i686-linux/IO.pm /usr/local/devperl/lib/5.00554/i686-linux/IO/Seekable.pm $ cat `pmload IO::Socket` | wc -l 4015 $ oldperl -S pmload Tk /usr/lib/perl5/site_perl/Tk/Pretty.pm /usr/lib/perl5/Symbol.pm /usr/lib/perl5/site_perl/Tk/Frame.pm /usr/lib/perl5/site_perl/Tk/Toplevel.pm /usr/lib/perl5/strict.pm /usr/lib/perl5/Exporter.pm /usr/lib/perl5/vars.pm /usr/lib/perl5/site_perl/auto/Tk/Wm/autosplit.ix /usr/lib/perl5/site_perl/auto/Tk/Widget/autosplit.ix /usr/lib/perl5/site_perl/Tk.pm /usr/lib/perl5/i386-linux/5.00404/DynaLoader.pm /usr/lib/perl5/site_perl/auto/Tk/Frame/autosplit.ix /usr/lib/perl5/site_perl/auto/Tk/Toplevel/autosplit.ix /usr/lib/perl5/Carp.pm /usr/lib/perl5/site_perl/auto/Tk/autosplit.ix /usr/lib/perl5/site_perl/Tk/CmdLine.pm /usr/lib/perl5/site_perl/Tk/MainWindow.pm /usr/lib/perl5/site_perl/Tk/Submethods.pm /usr/lib/perl5/site_perl/Tk/Configure.pm /usr/lib/perl5/AutoLoader.pm /usr/lib/perl5/site_perl/Tk/Derived.pm /usr/lib/perl5/site_perl/Tk/Image.pm /usr/lib/perl5/site_perl/Tk/Wm.pm /usr/lib/perl5/site_perl/Tk/Widget.pm
If the programmers used a delayed require, those files won't show up. Furthermore, this doesn't show all possible files that get opened, just those that those up in %INC. Most systems have a way to trace system calls. You can use this to find the real answer. First, get a baseline with no modules loaded.
require
$ strace perl -e 1 2>&1 | perl -nle '/^open\("(.*?)".* = [^-]/ && print $1' /etc/ld.so.cache /lib/libnsl.so.1 /lib/libdb.so.2 /lib/libdl.so.2 /lib/libm.so.6 /lib/libc.so.6 /lib/libcrypt.so.1 /dev/null $ strace perl -e 1 2>&1 | grep -c '^open.*= [^-]' 8
Now add module loads and see what you get:
$ strace perl -MIO::Socket -e 1 2>&1 | grep -c '^open.*= [^-]' 24 $ strace perl -MTk -e 1 2>&1 | grep -c '^open.*= [^-]' 35
Devel::Loaded, plxload(1).
Copyright (c) 1999 Tom Christiansen
This is free software. You may modify it and distribute it under Perl's Artistic Licence. Modified versions must be clearly indicated.
To install Devel::Loaded, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Devel::Loaded
CPAN shell
perl -MCPAN -e shell install Devel::Loaded
For more information on module installation, please visit the detailed CPAN module installation guide.