SEQUENCE is the character sequence to bind to. These should be written as <a href="index.html#escapes">fish escape sequences</a>. 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, @key{Alt,w} can be written as `\ew`. The control character can be written in much the same way using the `\c` escape, for example @key{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.)
`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 <a href="#function">function</a> 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.
If such a script produces output, the script needs to finish by calling `commandline -f repaint` in order to tell fish that a repaint is in order.
Key bindings are not saved between sessions by default. To save custom keybindings, edit the `fish_user_key_bindings` function and insert the appropriate `bind` statements.