Bash provides two modes for command line editing - emacs and vi. Emacs editing mode is the default and I already wrote an article and created a cheat sheet for this mode.
This time I am going to introduce you to bash’s vi editing mode and give out a detailed cheat sheet with the default keyboard mappings for this mode.
The difference between the two modes is what command each key combination (or key) gets bound to. You may inspect your current keyboard mappings with bash’s built in bind command:
$ bind -P
abort can be found on "\C-g", "\C-x\C-g", "\M-\C-g".
accept-line can be found on "\C-j", "\C-m".
alias-expand-line is not bound to any keys
...
To get into the vi editing mode type
$ set -o vi
in your bash shell (to switch back to emacs editing mode, type set -o emacs).
If you are used to a vi text editor you will feel yourself at home.
The editing happens in two modes - command mode and insert mode. In insert mode everything you type gets output to the terminal, but in the command mode the keys are used for various commands.
Here are a few examples with screenshots to illustrate the vi editing mode.
Let ’[i]’ be the position of cursor in insert mode in all the examples and ’[c]’ be the position of cursor in command mode.
Examples:
Once you have changed the readline editing mode to vi (by typing set -o vi), you will be working in insert mode.
The example will be performed on this command:
$ echo arg1 arg2 arg3 arg4[i]
Example 1:
Suppose you have typed a command with a few arguments and want to insert another argument before an argument which is three words backward.
$ echo arg1 (want to insert arg5 here) arg2 arg3 arg4[i]
Hit ’ESC’ to switch to command mode and press ’3’ followed by ’B’:
$ echo arg1 [c]arg2 arg3 arg4
Alternatively you could have hit ’B’ three times: ’BBB’.
Now, enter insert mode by hitting ’i’ and type ’arg5 ‘
$ echo arg1 arg5 [i]arg2 arg3 arg4
Example 2:
Suppose you wanted to change arg2 to arg5:
$ echo arg1 [c]arg2 arg3 arg4
To do this, you can type ’cw’ which means ‘change word’ and just type out ’arg5’:
$ echo arg1 arg5[c] arg3 arg4
Or even quicker, you can type ’f2r5’, where ’f2’ moves the cursor right to next occurrence of character ’2’ and ’r5’ replaces the character under the cursor with character ’5’.
Example 3:
Suppose you typed a longer command and you noticed that you had made several mistakes, and wanted to do the correction in the vi editor itself. You can type ’v’ to edit the command in the editor and not on the command line!
Example 4:
Suppose you typed a long command and remembered that you had to execute another one before it. No need to erase the current command! You can switch to command mode by hitting ESC and then type ’#’ which will send the current command as a comment in the command history. After you type the command you had forgotten, you may go two commands back in history by typing ’kk’ (or ’2k’), erase the ’#’ character which was appended as a comment and execute the command, this makes the whole command look like ’ESC 2k0x ENTER’.
These are really basic examples, and it doesn’t get much more complex than this. You should check out the cheat sheet for other tips and examples, and try them out!
To create the cheat sheet, I downloaded bash-2.05b source code and scanned through lib/readline/vi_keymap.c source code file and lib/readline/vi_mode.c to find all the default key bindings.
It turned out that the commands documented in vi_keymap.c were all documented in man 3 readline and I didn’t find anything new.
After that I checked bashline.c source file function initialize_readline to find how the default keyboard shortcuts were changed. I found that ’CTRL-e’ (which switched from vi mode to emacs) got undefined, ’v’ got defined which opens the existing command in the editor, and ’@’ which replaces a macro key (char) with the corresponding string.
The cheat sheet includes:
- Commands for entering input mode,
- Basic movement commands,
- Character finding commands,
- Character finding commands,
- Deletion commands,
- Undo, redo and copy/paste commands,
- Commands for history manipulation,
- Completion commands,
- A few misc. commands, and
- Tips and examples
http://www.catonmat.net/blog/wp-content/plugins/wp-downloadMonitor/user_uploads/bash-vi-editing-mode-cheat-sheet.txt
.---------------------------------------------------------------------------.
| |
| Readline VI Editing Mode |
| Default Keyboard Shortcuts for Bash |
| Cheat Sheet |
| |
'---------------------------------------------------------------------------'
| Peteris Krumins (peter@catonmat.net), 2008.01.08 |
| http://www.catonmat.net - good coders code, great reuse |
| |
| Released under the GNU Free Document License |
'---------------------------------------------------------------------------'
======================== Keyboard Shortcut Summary ========================
.--------------.------------------------------------------------------------.
| | |
| Shortcut | Description |
| | |
'--------------'------------------------------------------------------------'
| Switching to COMMAND Mode: |
'--------------.------------------------------------------------------------'
| ESC | Switch to command mode. |
'--------------'------------------------------------------------------------'
| Commands for Entering INPUT Mode: |
'--------------.------------------------------------------------------------'
| i | Insert before cursor. |
'--------------+------------------------------------------------------------'
| a | Insert after cursor. |
'--------------+------------------------------------------------------------'
| I | Insert at the beginning of line. |
'--------------+------------------------------------------------------------'
| A | Insert at the end of line. |
'--------------+------------------------------------------------------------'
| c<mov. comm> | Change text of a movement command <mov. comm> (see below). |
'--------------+------------------------------------------------------------'
| C | Change text to the end of line (equivalent to c$). |
'--------------+------------------------------------------------------------'
| cc or S | Change current line (equivalent to 0c$). |
'--------------+------------------------------------------------------------'
| s | Delete a single character under the cursor and enter input |
| | mode (equivalent to c[SPACE]). |
'--------------+------------------------------------------------------------'
| r | Replaces a single character under the cursor (without |
| | leaving command mode). |
'--------------+------------------------------------------------------------'
| R | Replaces characters under cursor. |
'--------------+------------------------------------------------------------'
| v | Edit (and execute) the current command in the text editor. |
| | (an editor defined in $VISUAL or $EDITOR variables, or vi |
'--------------'------------------------------------------------------------'
| Basic Movement Commands (in command mode): |
'--------------.------------------------------------------------------------'
| h | Move one character right. |
'--------------+------------------------------------------------------------'
| l | Move one character left. |
'--------------+------------------------------------------------------------'
| w | Move one word or token right. |
'--------------+------------------------------------------------------------'
| b | Move one word or token left. |
'--------------+------------------------------------------------------------'
| W | Move one non-blank word right. |
'--------------+------------------------------------------------------------'
| B | Move one non-blank word left. |
'--------------+------------------------------------------------------------'
| e | Move to the end of the current word. |
'--------------+------------------------------------------------------------'
| E | Move to the end of the current non-blank word. |
'--------------+------------------------------------------------------------'
| 0 | Move to the beginning of line |
'--------------+------------------------------------------------------------'
| ^ | Move to the first non-blank character of line. |
'--------------+------------------------------------------------------------'
| $ | Move to the end of line. |
'--------------+------------------------------------------------------------'
| % | Move to the corresponding opening/closing bracket. |
'--------------'------------------------------------------------------------'
| Character Finding Commands (these are also Movement Commands): |
'--------------.------------------------------------------------------------'
| fc | Move right to the next occurance of char c. |
'--------------+------------------------------------------------------------'
| Fc | Move left to the previous occurance of c. |
'--------------+------------------------------------------------------------'
| tc | Move right to the next occurance of c, then one char |
| | backward. |
'--------------+------------------------------------------------------------'
| Tc | Move left to the previous occurance of c, then one char |
| | forward. |
'--------------+------------------------------------------------------------'
| ; | Redo the last character finding command. |
'--------------+------------------------------------------------------------'
| , | Redo the last character finding command in opposite |
| | direction. |
'--------------+------------------------------------------------------------'
| | | Move to the n-th column (you may specify the argument n by |
| | typing it on number keys, for example, 20|) |
'--------------'------------------------------------------------------------'
| Deletion Commands: |
'--------------.------------------------------------------------------------'
| x | Delete a single character under the cursor. |
'--------------+------------------------------------------------------------'
| X | Delete a character before the cursor. |
'--------------+------------------------------------------------------------'
| d<mov. comm> | Delete text of a movement command <mov. comm> (see above). |
'--------------+------------------------------------------------------------'
| D | Delete to the end of the line (equivalent to d$). |
'--------------+------------------------------------------------------------'
| dd | Delete current line (equivalent to 0d$). |
'--------------+------------------------------------------------------------'
| CTRL-w | Delete the previous word. |
'--------------+------------------------------------------------------------'
| CTRL-u | Delete from the cursor to the beginning of line. |
'--------------'------------------------------------------------------------'
| Undo, Redo and Copy/Paste Commands: |
'--------------.------------------------------------------------------------'
| u | Undo previous text modification. |
'--------------+------------------------------------------------------------'
| U | Undo all previous text modifications. |
'--------------+------------------------------------------------------------'
| . | Redo the last text modification. |
'--------------+------------------------------------------------------------'
| y<mov. comm> | Yank a movement into buffer (copy). |
'--------------+------------------------------------------------------------'
| yy | Yank the whole line. |
'--------------+------------------------------------------------------------'
| p | Insert the yanked text at the cursor. |
'--------------+------------------------------------------------------------'
| P | Insert the yanked text before the cursor. |
'--------------'------------------------------------------------------------'
| Commands for Command History: |
'--------------.------------------------------------------------------------'
| k | Insert the yanked text before the cursor. |
'--------------+------------------------------------------------------------'
| j | Insert the yanked text before the cursor. |
'--------------+------------------------------------------------------------'
| G | Insert the yanked text before the cursor. |
'--------------+------------------------------------------------------------'
| /string or | Search history backward for a command matching string. |
| CTRL-r | |
'--------------+------------------------------------------------------------'
| ?string or | Search history forward for a command matching string. |
| CTRL-s | (Note that on most machines Ctrl-s STOPS the terminal |
| | output, change it with `stty' (Ctrl-q to resume)). |
'--------------+------------------------------------------------------------'
| n | Repeat search in the same direction as previous. |
'--------------+------------------------------------------------------------'
| N | Repeat search in the opposite direction as previous. |
'--------------'------------------------------------------------------------'
| Completion commands: |
'--------------.------------------------------------------------------------'
| TAB or = or | List all possible completions. |
| CTRL-i | |
'--------------+------------------------------------------------------------'
| * | Insert all possible completions. |
'--------------'------------------------------------------------------------'
| Miscellaneous commands: |
'--------------.------------------------------------------------------------'
| ~ | Invert case of the character under cursor and move a |
| | character right. |
'--------------+------------------------------------------------------------'
| # | Prepend '#' (comment character) to the line and send it to |
| | the history. |
'--------------+------------------------------------------------------------'
| _ | Inserts the n-th word of the previous command in the |
| | current line. |
'--------------+------------------------------------------------------------'
| 0, 1, 2, ... | Sets the numeric argument. |
'--------------+------------------------------------------------------------'
| CTRL-v | Insert a character literally (quoted insert). |
'--------------+------------------------------------------------------------'
| CTRL-r | Transpose (exchange) two characters. |
'--------------'------------------------------------------------------------'
===========================================================================
.---------------------------------------------------------------------------.
| Peteris Krumins (peter@catonmat.net), 2008.01.08. |
| http://www.catonmat.net - good coders code, great reuse |
| |
| Released under the GNU Free Document License |
'---------------------------------------------------------------------------'
–
Liu Lantao
College of Information Science and Technology, Beijing Normal University
EMAIL: liulantao ( at ) gmail ( dot ) com ;
WEBSITE: http://www.liulantao.com/ .
——
