When I'm using a UITS shared central system at IU, why doesn't my keyboard's Backspace key work properly?

Note: The information in this document refers to the key labeled Backspace on Windows-compatible keyboards and delete on Macintosh keyboards. Your Windows keyboard may also have a Delete key, but it doesn't perform the same function as the Mac's delete (or Windows Backspace) key.

When you're logged into a UITS shared central system at Indiana University, if pressing your keyboard's Backspace (or delete) key does not perform a destructive backspace (i.e., it doesn't delete the character to the left of the cursor while moving the cursor to the left), the SSH client you're using (e.g., PuTTY or Mac OS X Terminal) is probably sending the wrong definition of the Backspace (or delete) key to the shared system to which you are connected.

In computing, a delete, a destructive backspace, and a non-destructive backspace are all different functions, which normally correspond to three different key codes. These, in turn, may correspond to three different keys, depending on your keyboard.

For example, on a Windows-compatible keyboard:

  • Pressing the left arrow key performs a non-destructive backspace, which moves the cursor one space to the left, but does not delete the previous character.
  • Pressing the Delete key performs a delete (sometimes called a forward delete), which deletes the character beneath the cursor and moves all following characters back one space.
  • Pressing the Backspace key, depending on how the key is defined, may either perform a destructive backspace (deleting the character to the left of the cursor while moving the cursor to the left) or move the cursor to the beginning of the line.

Many SSH clients let you modify the setting that controls how the Backspace (or delete) key functions. Depending on your client, look for a "Profile Settings", "Window Settings", or "Keyboard" option in the preferences or configuration panel. Generally, users on IU central systems prefer Backspace (or delete) to perform a destructive backspace (ASCII code 127).

For example, in PuTTY, right-click the top border of an open terminal window and then select Change Settings. In the PuTTY Configuration window, on the left, under the Terminal category, click Keyboard. Then, on the right, under "The Backspace key", make sure Control-? (127) is selected, and then close the PuTTY Configuration window.

Note: In Emacs, pressing the Backspace (or delete) key will open Emacs Help.

This is document aast in the Knowledge Base.
Last modified on 2017-01-18 16:48:16.

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