Control Characters

    change the behavior of the terminal or text display. A control character is a CONTROL + key combination (pressed simultaneously). A control character may also be written in octal or hexadecimal notation, following an escape.

    Control characters are not normally useful inside a script.

        *

          Ctl-A

          Moves cursor to beginning of line of text (on the command-line).
        *

          Ctl-B

          Backspace (nondestructive).
        *

          Ctl-C

          Break. Terminate a foreground job.
        *

          Ctl-D

          Log out from a shell (similar to exit).

          EOF (end-of-file). This also terminates input from stdin.

          When typing text on the console or in an xterm window, Ctl-D erases the character under the cursor. When there are no characters present, Ctl-D logs out of the session, as expected. In an xterm window, this has the effect of closing the window.
        *

          Ctl-E

          Moves cursor to end of line of text (on the command-line).
        *

          Ctl-F

          Moves cursor forward one character position (on the command-line).
        *

          Ctl-G

          BEL. On some old-time teletype terminals, this would actually ring a bell. In an xterm it might beep.
        *

          Ctl-H

          Rubout (destructive backspace). Erases characters the cursor backs over while backspacing.
        *

          Ctl-I

          Horizontal tab.
        *

          Ctl-J

          Newline (line feed). In a script, may also be expressed in octal notation -- '\012' or in hexadecimal -- '\x0a'.
        *

          Ctl-K

          Vertical tab.

          When typing text on the console or in an xterm window, Ctl-K erases from the character under the cursor to end of line. Within a script, Ctl-K may behave differently, as in Lee Lee Maschmeyer's example, below.
        *

          Ctl-L

          Formfeed (clear the terminal screen). In a terminal, this has the same effect as the clear command. When sent to a printer, a Ctl-L causes an advance to end of the paper sheet.
        *

          Ctl-M

          Carriage return.

        *

          Ctl-N

          Erases a line of text recalled from history buffer [7] (on the command-line).
        *

          Ctl-O

          Issues a newline (on the command-line).
        *

          Ctl-P

          Recalls last command from history buffer (on the command-line).
        *

          Ctl-Q

          Resume (XON).

          This resumes stdin in a terminal.
        *

          Ctl-R

          Backwards search for text in history buffer (on the command-line).
        *

          Ctl-S

          Suspend (XOFF).

          This freezes stdin in a terminal. (Use Ctl-Q to restore input.)
        *

          Ctl-T

          Reverses the position of the character the cursor is on with the previous character (on the command-line).
        *

          Ctl-U

          Erase a line of input, from the cursor backward to beginning of line. In some settings, Ctl-U erases the entire line of input, regardless of cursor position.
        *

          Ctl-V

          When inputting text, Ctl-V permits inserting control characters. For example, the following two are equivalent:

          echo -e '\x0a'
          echo

          Ctl-V is primarily useful from within a text editor.
        *

          Ctl-W

          When typing text on the console or in an xterm window, Ctl-W erases from the character under the cursor backwards to the first instance of whitespace. In some settings, Ctl-W erases backwards to first non-alphanumeric character.
        *

          Ctl-X

          In certain word processing programs, Cuts highlighted text and copies to clipboard.
        *

          Ctl-Y

          Pastes back text previously erased (with Ctl-U or Ctl-W).
        *

          Ctl-Z

          Pauses a foreground job.

          Substitute operation in certain word processing applications.

          EOF (end-of-file) character in the MSDOS filesystem.