Pressing K when over a keyword in vim usually opens the keyword's manpage. In Python it invokes
pydoc instead. I wanted it to open PHP's online documentation when I press it over a function name in PHP. Easy.
I wrote a tiny shell script in my ~/bin directory first, phpman:
I then added to my .vimrc the line
autocmd FileType php set keywordprg=phpman
Done. And using
sensible-browser has the added bonus that it'll run whatever my preferred graphical browser is when I am in X or a textmode browser when I'm not.