In Unix/Linux you can execute your perl scripts by typing “perl <filename>” at command prompt. But before you do that make sure you have both Perl and its Tk module. Most linux distributions have perl – but quite a few don’t have the Tk module. Make sure that the system you are using have the Tk module. If you don’t have it, go to http://www.cpan.org and download the perl module. Or you can use the perl’s CPAN module to install the Tk module. To do this, open a terminal and enter the following command
perl -MCPAN -e shell
cpan> install Bundle::CPAN
cpan> reload cpan
cpan> install Tk

via Perl/Tk Tutorial – Create GUI with Perl’s Tk Module.