Strangely, the investment bank I used to work at relied heavily on Perl, without most people even realising it. A huge volume of live rates information formed the basis for a large number of Seriously Enterprise Applications, all with architecture groups and best practice gurus and all that stuff. What was ironic was how the rates got into the bank: six instances of a single Perl script that almost noone knew about, connected to the Reuters Market Data System. And the reason that it was so poorly known was simple: it was cronned to start and stop at particular times during the day, and in the four years that I was there, it went down once, when the box it was on suffered a hardware failure.

Funnily enough, a few more people knew about it after that, whereupon I got funding and contingency hardware thrown at me until I could confidently tell the powers that be that a box failure would be followed up by immediate failover and a whole bunch of alerts being generated.

Overall, I think that's where Perl does a really good job: in holding stuff together. While the Rubyists and Pythonistas are arguing over who's got the better language, Perl hackers are just getting stuff done.