Restoring

to get the latest latest

cd public_html
wget http://wordpress.org/latest.tar.gz

unziping that will create a directory called wordpress clobbering the existing install so you might want to temporarily rename the existing site

mv wordpress wordpress0

Then unzip the package using:

tar -xzvf latest.tar.gz 

then rename the nwe install to some convenient name

mv wordpress wordpress1

then rename the existing intall back to wordpess so it works

mv wordpress0 wordpress

(you can also do renaming from fetch)