How can I get the version and location of an installed Perl module?

Question

Is there a smart way to detect whether a certain Perl module has been installed in your system? My old sutpid way is to write a Perl script in which the only thing I do is just to use the module. If nothing croaks when I run the detect script, then I know the module has been installed, although I still don't know which version and where the module has been installed .

thanks in advance.

Answer 1

Something like:

perl -MModule -e 'print "$Module::VERSION\n"' 2>/dev/null || echo "Not installed"

would give you the version of a given module, or tell you it isn't installed. Usage would look like:

perl -MXML::Parser -e 'print "$XML::Parser::VERSION\n"' 2>/dev/null || echo "Not installed"

To find the module path, you could examine @INC to find possible locations, or you could perhaps look into perlwhich. There is also pmpath from pmtools.

Answer 2

instmodsh

NAME
       instmodsh - A shell to examine installed modules

SYNOPSIS
           instmodsh

DESCRIPTION
       A little interface to ExtUtils::Installed to examine installed modules, validate your packlists and even create a tarball from an installed module.

SEE ALSO
       ExtUtils::Installed

Answer 3

Use pmvers. Like the name suggests, it shows the version of an installed module. If a module is not installed, it fails with the familiar error message: Can't locate … in @INC (@INC contains: …)

Use pmpath from the same distribution to find a module's installation path.

Answer 4

I use these bash function/Perl oneliners to find the version number and location of Perl modules:

# equivalent to perldoc -l <module>
perlwhere() {
    perl -wle'eval "require $ARGV[0]" or die; ($mod = $ARGV[0]) =~ s|::|/|g; print $INC{"${mod}.pm"}' $1
}

perlversion() {
    perl -M$1 -wle'print $ARGV[0]->VERSION' $1
}

: [ether ~].2$; perlwhere Test::More
/usr/lib/perl5/5.8.8/Test/More.pm
: [ether ~].2$; perlversion Test::More
0.94

Answer 5

The pmvers utility and the other pmtools will do what you need. Otherwise here is a one-liner to find a module version:

perl -le 'eval "require $ARGV[0]" and print $ARGV[0]->VERSION' Some::Module

Answer 6

The shortest thing I know of that doesn't involve a script or shell alias:

$ perl -MFoo::Bar\ 99
Foo::Bar version 99 required--this is only version 1.234.

(or the usual message about not being in @INC if it's not installed)

For the curious, this is the same as perl -e 'use Foo::Bar 99'.

Answer 7

Here's a program which does that:

!/usr/bin/perl

testmod - test to see if a module is available

use strict; use warnings;

my $mod = (shift @ARGV) || die "usage: $0 module\n";

convert module-name to path

my $file = $mod; $file =~ s{::}{/}gsmx; $file .= '.pm';

Pull in the module, if it exists

eval { require $file } or die "can't find module $mod\n";

Get the version from the module, if defined

my $ver; { no strict 'refs'; $ver = ${$mod . "::VERSION"} || 'UNKNOWN'; }

And its location

my $from = $INC{$file}; print "module $mod is version $ver loaded from $from\n";