I think as startups grow, they tend to end up with something of a frankenstein-ish mix of languages as they write bits that are well suited to each language. For us I ended up checking C++, Java, Javascript, Perl and Ruby, though we have little bits also in Python, Scala and PHP as well.
As a sidenote, we track which programming languages our webservices customers are using and I made a graph of such here:
I find it a little surprising that you use both perl and ruby. Is it an issue of "one guy likes perl, another likes ruby", or are there things you find easier in one than the other, in both directions?
Or is ruby just there for your API and your internal stuff is perl?
I hadn't done web programming for about 8 years when we founded Directed Edge, and the last time I had Perl was still riding high. So the old stuff, and a lot of the maintenance scripts are in Perl. Ruby has, however, begun eating into the Perl usage.
I still find Perl a little better suited for straight text-processing tasks, not to mention that it's a lot faster than Ruby for such. It's tempting to say, "It doesn't matter." but when you're running tasks that process several gigs of text, the difference between waiting 5 minutes for a job to finish vs. 20 can impact overall productivity.
I feel the same way about text processing. I have yet to see anything else that rips through text like perl does. Over the summer, I rewrote a powershell script in perl and got three orders of magnitude improvement (reliably), all in the constant factor. Powershell is probably the worst language for text processing (it encapsulates every line in an object before passing it between processes in the stream), but I still found this impressive.
I do actually have a perl script that generates all the obnoxious boilerplate a rails application that does something slightly differen from what DHH likes requires, so I have no doubt that such a mix of languages may come to pass in other places, too.
As a sidenote, we track which programming languages our webservices customers are using and I made a graph of such here:
http://blog.directededge.com/2010/05/30/what-programming-lan...