You need to either fork or use threads (depending perhaps on the OS you are using). Note though that Tk can get grumpy working in a forked/threaded environment if you are not careful.

Peruse the following node for related discussion: Re: Perl/Tk question about starting programs via a button and PerlTk on a thread...

True laziness is hard work

In reply to Re: Launch External App in Tk And Return by GrandFather
in thread Launch External App in Tk And Return by ~~David~~

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