Edit Menu

Undo Reverses (one at a time) a series of editor actions (except Save)
Redo Reverses (one at a time) a series of Undo commands
Cut Deletes the current selection and places it on the clipboard
Copy Copies the current selection to the clipboard
Paste Pastes the contents of the clipboard at the insert point

Delete Line Deletes the line the cursor is on

Insert File Inserts a file at the cursor position (activates a filechooser).

Find Finds a string of text
Replace Finds a string of text and then replaces it with a string you specify
Find Forward Finds the next forward match of the current search text
Find Backward Finds the next backward match of the current search text

Go To Line Takes you to a specified line in the file

See also:

Editing Source Code
Editor Menu and Toolbar Commands
Basic Editing