There are many code syntax highlighter plugins available for WordPress (e.g. iG Syntax Highlighter, WP-Syntax, etc) but almost all of them have a problem. They want you to write the code in “HTML editing mode”. If you use any kind of WYSIWYG or visual editors (like built in TinyMCE or offline clients’ similar modes), there is a grave problem. Your code becomes garbled. e.g.
If you intend to write:
cat abc > /dev/null
It might turn out as: