opening file from text wrangler to terminal
Open up Terminal.

Your Desktop is at ~/Desktop (the ~ is a shortcut for your home folder) so cd ~/Desktopreturn to go there then less test.txtreturn

By the way, if you are going to use TextWrangler and Terminal you might want to visit http://www.barebones.com/support/textwrangler/ and download the TextWrangler command line tools which allow you to open a file in TextWrangler from the command line, among other things.