Shell Commands Inside NEdit

NEdit allows you to:

Run a command on an entire buffer (ex. sort, wc) using a menu item under the Shell menu (you can, of course, add commands to this menu yourself).
Run the current line of text, or currently selected text, as if you'd typed it into your terminal window -- stdout and stderr output appears below the text you just executed. (Shell --> Execute Command Line)
Select some text, then filter that text through any command you like. (Shell --> Filter Selection)
Run a command by typing it in to a dialog, and have the output appear in your file. (Shell --> Execute Command)