how to install the gedit regex/regexp plugin for unity in ubuntu linux 11.10 oneiric ocelot

download this file http://live.gnome.org/Gedit/Plugins?action=AttachFile&do=get&target=regex_replace-gedit3.tar.gz

close all instances of gedit

open a terminal/console and move to where you downloaded the file, e.g. /home/myuser/Downloads

cd /home/myuser/Downloads
tar xzvf regex_replace-gedit3.tar.gz
mkdir -p ~/.local/share/gedit/plugins
mv regex_replace ~/.local/share/gedit/plugins

start gedit > edit > preferences > plugins > put a checkmark on "regular expressions"
now when you want to use regular expressions in search and replace you go here: search > regular expressions

source: http://halfhourhacks.blogspot.com/2008/03/gedit-regular-expression-plugin.html