xterm, terminal, shortcut keys, function keys

time: 2016-07-16-Sat 14:36:57

Xterm and other terminals through terminal control characters based on the type of terminal emulation. Commons terminal type are VT100…

Note: Most of these keystrokes come from the readline library, and have nothing to do with the terminal type or terminal emulator used (except that some terminals emulators don’t play well with control/meta keys). When using bash (which uses readline), a list of shortcuts it offers is obtained by entering “bind -P” at the command prompt.

Clearing functions

Keyboard Commands	Function
ALT-Backspace	removes words, not single chars. (same as CTRL+W)
Backspace	deletes characters to the left or the cursor (this may vary depending on settings)
Ctrl-7 or Ctrl-Shift–	removes a number? of characters from the end
Ctrl-d	deletes characters to the right of cursor, if no characters, logs out and closes terminal
Ctrl-h or Ctrl-8 or Ctrl-Shift-/	deletes characters to the left or the cursor
Ctrl-k	clear all characters after the cursor
Ctrl-l	clear screen
Ctrl-u	clears all characters before the cursor
Ctrl-w	clears word before the cursor. a word is set of characters separated by spaces
Delete	deletes characters to the right of cursor (this may vary depending on settings)

Cursor movment

Keyboard Commands	Function
Ctrl-a or Home	returns cursor to Home, to the beginning of the line
Crtl-b	movers cursor to the left (backward)
Ctrl+e or End	Moves cursor to the end of the line
Ctrl-f	moves cursor right (forward)
Ctrl-n	same as down arrow
Ctrl-p	same as up arrow
Ctrl-[b (^[b)	move cursor backward by one word
Ctrl-[f (^[f)	move cursor forward by one word

Other

Keyboard Commands	Function
Ctrl-/	undo: changes made to a previous command, clear current cmd typed
Ctrl-[	escape, similar to Tab but not the same]
Ctrl-a	returns cursor to Home
Crtl-b	movers cursor to the left (backward)
Ctrl-c	kill process
Ctrl-e	return Terminal Status ???
Ctrl-f	moves cursor right (forward)
Ctrl-g	Bell (beep)
Ctrl-i	same as tab
Ctrl-m or Ctrl-j	carriage return, like enter
Ctrl-n	next command, if there is one, same a down arrow
Ctrl-o	Executes command without clearing the line
Ctrl-p	previous command, like up arrow
Ctrl-q	Unlocks the screen after a XOFF signal. XON signal for software flow control.
Ctrl-r	search: Reverse search for previous commands matching the pattern entered
Ctrl-s	In effect, locks the screen (Ctrl-q unlocks it). XOFF signal for software flow control.
Ctrl-t	Switched the character before the cursor with the one under the cursor
Ctrl-v	displays next typed characters (code?)
Ctrl-x	?
Ctrl-y	paste deleted content by clearing commands(ctrl-k, ctrl-u or ctrl-w)
Ctrl-z	pauses process and places it in terminal background (resume with command ‘fg’)

Determine “essentials” of keys

When you don’t known what the essentials of the shortcut keys you pressed, use Linux command showkey -ask to determine them. for example:

1. type showkey -ask
2. input Alt-leftarrow — this shortcut key is usually defined by the termial emulators
3. the output will be ^[b, which means press combination of ctrl key and [, and then press b, the cursor will move backward by one word
4. so, ^[b is “essential” of move cursor backwards by one word

References

How to use short-cut keys in xterm and other terminals Xterm Control Sequences key binding table?

Fun time

How many ways to execute a command? Say, ls

1. with Enter

    ls<Enter>
   

2. with ctrl-j

    ls<ctrl-j>
   

3. with ctrl-m

    ls<ctrl-m>
   

4. with ctrl-o

    ls<ctrl-o>