You already have perl installed, or else you would have gotten an Operating System error when you ran it. The way you're calling the script is correct.

To check perl's version:

perl -v

This is perl 5, version 24, subversion 0 (v5.24.0) built for x86_64-li
+nux
(with 1 registered patch, see perl -V for more detail)

...
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Upgrading (or otherwise mucking about in any way) your system perl is *highly* recommended against. I, personally have hosed a system or two in the past by doing this (same goes for system Python). You're on Linux, so I say take a look at Perlbrew. If you must upgrade your system perl, use Ubuntu's package manager, and do a complete backup/snapshot before you do.

To both check if a module is installed, and get its version if it is:

perl -MData::Dumper -E 'say Data::Dumper->VERSION'
2.160
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If the module isn't installed, you'll get a similar error to what you got:

perl -MTkx -E 'say Tkx->VERSION'

Can't locate Tkx.pm in @INC (you may need to install the Tkx module) (
+@INC contains: /home/spek/perl5/perlbrew/perls/perl-5.24.0/lib/site_p
+erl/5.24.0/x86_64-linux /home/spek/perl5/perlbrew/perls/perl-5.24.0/l
+ib/site_perl/5.24.0 /home/spek/perl5/perlbrew/perls/perl-5.24.0/lib/5
+.24.0/x86_64-linux /home/spek/perl5/perlbrew/perls/perl-5.24.0/lib/5.
+24.0 .).
BEGIN failed--compilation aborted.
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The -M flag is akin to having use Module::Name within a perl script.

To install a module, use cpan or if it's installed on your system, cpanm:

cpan install Tkx
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...or:

cpanm Tkx
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