SEQUENCE is the character sequence to bind to. These should be written as :ref:`fish escape sequences <escapes>`. For example, because pressing the Alt key and another character sends that character prefixed with an escape character, Alt-based key bindings can be written using the ``\e`` escape. For example, :kbd:`Alt+w` can be written as ``\ew``. The control character can be written in much the same way using the ``\c`` escape, for example :kbd:`Control+X` (^X) can be written as ``\cx``. Note that Alt-based key bindings are case sensitive and Control-based key bindings are not. This is a constraint of text-based terminals, not ``fish``.
The default key binding can be set by specifying a ``SEQUENCE`` of the empty string (that is, ``''`` ). It will be used whenever no other binding matches. For most key bindings, it makes sense to use the ``self-insert`` function (i.e. ``bind '' self-insert``) as the default keybinding. This will insert any keystrokes not specifically bound to into the editor. Non- printable characters are ignored by the editor, so this will not result in control sequences being printable.
If the ``-k`` switch is used, the name of the key (such as 'down', 'up' or 'backspace') is used instead of a sequence. The names used are the same as the corresponding curses variables, but without the 'key\_' prefix. (See ``terminfo(5)`` for more information, or use ``bind --key-names`` for a list of all available named keys.) If used in conjunction with the ``-s`` switch, ``bind`` will silently ignore bindings to named keys that are not found in termcap for the current ``$TERMINAL``, otherwise a warning is emitted.
``COMMAND`` can be any fish command, but it can also be one of a set of special input functions. These include functions for moving the cursor, operating on the kill-ring, performing tab completion, etc. Use ``bind --function-names`` for a complete list of these input functions.
When ``COMMAND`` is a shellscript command, it is a good practice to put the actual code into a `function <#function>`__ and simply bind to the function name. This way it becomes significantly easier to test the function while editing, and the result is usually more readable as well.
When multiple ``COMMAND``\s are provided, they are all run in the specified order when the key is pressed. Note that special input functions cannot be combined with ordinary shell script commands. The commands must be entirely a sequence of special input functions (from ``bind -f``) or all shell script commands (i.e., valid fish script).
If no ``SEQUENCE`` is provided, all bindings (or just the bindings in the specified ``MODE``) are printed. If ``SEQUENCE`` is provided without ``COMMAND``, just the binding matching that sequence is printed.
To save custom keybindings, put the ``bind`` statements into :ref:`config.fish <initialization>`. Alternatively, fish also automatically executes a function called ``fish_user_key_bindings`` if it exists.
Key bindings may use "modes", which mimics Vi's modal input behavior. The default mode is "default", and every bind applies to a single mode. The mode can be viewed/changed with the ``$fish_bind_mode`` variable.
-``-e`` or ``--erase`` Erase the binding with the given sequence and mode instead of defining a new one. Multiple sequences can be specified with this flag. Specifying ``-a`` or ``--all`` with ``-M`` or ``--mode`` erases all binds in the given mode regardless of sequence. Specifying ``-a`` or ``--all`` without ``-M`` or ``--mode`` erases all binds in all modes regardless of sequence.
-``--preset`` and ``--user`` specify if bind should operate on user or preset bindings. User bindings take precedence over preset bindings when fish looks up mappings. By default, all ``bind`` invocations work on the "user" level except for listing, which will show both levels. All invocations except for inserting new bindings can operate on both levels at the same time. ``--preset`` should only be used in full binding sets (like when working on ``fish_vi_key_bindings``).
-``backward-kill-path-component``, move one path component to the left of the cursor to the killring. A path component is everything likely to belong to a path component, i.e. not any of the following: `/={,}'\":@ |;<>&`, plus newlines and tabs.
-``repaint-mode`` reexecutes the fish_mode_prompt function and redraws the prompt. This is useful for vi-mode. If no fish_mode_prompt exists, it acts like a normal repaint.
The escape key can be used standalone, for example, to switch from insertion mode to normal mode when using Vi keybindings. Escape can also be used as a "meta" key, to indicate the start of an escape sequence, like for function or arrow keys. Custom bindings can also be defined that begin with an escape character.
fish waits for a period after receiving the escape character, to determine whether it is standalone or part of an escape sequence. While waiting, additional key presses make the escape key behave as a meta key. If no other key presses come in, it is handled as a standalone escape. The waiting period is set to 30 milliseconds (0.03 seconds). It can be configured by setting the ``fish_escape_delay_ms`` variable to a value between 10 and 5000 ms. This can be a universal variable that you set once from an interactive session.
