Obtaining and using the Vim plain text editor.

Installing Vim

Vim is probably already on your machine (Linux and Mac OS X). Proceed to using Vim, if it doesn't seem to be there see about getting Vim.

Using Vim

See also:
http://larc.ee.nthu.edu.tw/~cthuang/vim/files/vim-intro.html
http://vim.wikia.com/wiki/Vim_Tips_Wiki
http://data.agaric.com/raw/indent-lines-vim

Check for trailing whitespace

In normal (command) mode, type : and then:
/\s\+$

Enable Syntax Checking

With two lines in your .vimrc file (vi ~/.vimrc to edit or create it) you can enable

In normal (command) mode, type :make% and press enter to run the PHP syntax check. If there are any errors, it will list them for you and take you to the first one when you press enter again.

Resources

http://drupal.org/project/vimrc