18 Using rectangular region commands

Emacs has a set of commands which operate on the region as if it were rectangular. This turns out to be extremely useful when dealing with whitespace sensitive languages.

• C-x r o is "Open Rectangle".

  It will shift any text within the rectangle to the right side. Also see:

• C-x r t is "String Rectangle".

  It will replace any text within the rectangle with the given string on all the lines in the region. If comment-region didn’t already exist, you could use this instead, for example.

• C-x r d is "Delete Rectangle".

  It will delete the contents of the rectangle and move anything on the right over.

• C-x r r is "Copy Rectangle to Register".

  It will prompt you for a register number so it can save it for later.

• C-x r g is "Insert register".

  This will insert the contents of the given register, overwriting whatever happens to be within the target rectangle. (So make room)

• C-x r k is "Kill rectangle".

  Delete rectangle and save contents for:

• C-x r y is "Yank rectangle".

  This will insert the contents of the last killed rectangle.

As with all Emacs modifier combos, you can type C-x r C-h to find out what keys are bound beginning with the C-x r prefix.