Learn Perl! Perl has:
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* Great Community
* CPAN - With Perl you have one command to access literally tens of thousands of open sourced modules
* Awesome Tools:
- Moose for best way to model objects
- Plack for web application building
- perlbrew ...
And Perl is open source software among many other things.
I am programming Perl for a long time. I would say, to me, it is more or less a kind of identity.
It is free software. It has a great community. Perl can be used, for batch processing, web development (as you mentioned), data analysis and text manipulation. It is multi-platform. It can interact withe C, C++. Java, Python, etc.
Last but not least it has the CPAN (Comprehensive Perl Archive Network), a huge repository of free code. If you missing a functionality, surely you will find some options there.
Perl is healthy and growing and you can easily be part of its community.