I agree with you that a shell scripting language should be in every programmers toolkit (even DOS command prompt and batch files count). Also if a programmer is

I agree with you that a shell scripting language should be in every programmers toolkit (even DOS command prompt and batch files count). Also if a programmer is dealing with the web or web applications then JavaScript is a must. However I must disagree on the other two languages, they do not need to be added to the list. Regarding PHP, you don't actually need to know it, as once you know C (and HTML) you can easily interpret a PHP script, and make any minor modifications if need be. I would only say to learn PHP if you intend to actively develop in it (i.e. contribute actively to the development of an existing open-source PHP application), as I've found that the existing PHP applications to be sufficiently completed for my liking. As for Perl, you can just substitute Ruby or Python (both of which are on the list) for all of your text processing needs. Like the author I prefer Ruby, but both languages seem to have a reasonably powerful text processing library included.