JavaScript. Sure, in theory you can use it on the server for other things. Have you seen that happen lately?
Running on v8, it has an edge in terms of execution speed over other scripting languages. And the javascript syntax and semantics is something most of the developers are familiar with.
If you don't like writing nested closures, you have coffeescript which makes the code pretty, and also brings in some new features viz. list comprehensions, splats, satement modifiers etc.
EDIT: I don't hold that view because of the things I mentioned but I am pretty sure a lot of programmers do.
I will have to agree with you that PHP is perceived as a web language. Hopefully with more articles like these that perception will change.
They are a bad idea, in general. PHP is designed for a very specific purpose: Very quickly building web pages in a CGI or mod_php environment and spitting them out. Everything else is an afterthought, and it shows.
For example, if you try to manipulate the filesystem extensively using PHP you will eventually trip over its "stat cache". PHP caches the result of stat() calls, presumably assuming that, hey, it is more important to avoid redundantly calling stat() during the time-sensitive rendering of your web page than it is to actually return correct information about the state of the filesystem. I mean, how often do symlinks change or files get moved during the rendering of a typical web page? And how much web-page-rendering code really depends on being able to read a link, then read the link again after the link has changed on disk? You can afford to ignore that stuff at the language level, if you're PHP.
The result is that you have to learn about the stat cache and remember to call clearstatcache() all the time when manipulating the filesystem in PHP.
That's just one example of why it's better to use Ruby or Perl to write command-line scripts. These languages were designed with command-line scripting in mind. Indeed, this is the flip side of the reason why PHP eventually drove out Perl as a web development language: Perl was originally designed for command-line scripting, and PHP was originally designed for the web. Use tools for their proper purpose.
