DOKK / manpages / debian 12 / fish-common / fish_key_reader.1.en
FISH_KEY_READER(1) fish-shell FISH_KEY_READER(1)

fish_key_reader - explore what characters keyboard keys send

fish_key_reader [OPTIONS]

fish_key_reader is used to explain how you would bind a certain key sequence. By default, it prints the bind command for one key sequence read interactively over standard input.

If the character sequence matches a special key name (see bind --key-names), both bind CHARS ... and bind -k KEYNAME ... usage will be shown. In verbose mode (enabled by passing --verbose), additional details about the characters received, such as the delay between chars, are written to standard error.

The following options are available:

Begins a session where multiple key sequences can be inspected. By default the program exits after capturing a single key sequence.
Tells fish_key_reader to output timing information and explain the sequence in more detail.
Displays help about using this command.
Displays the current fish version and then exits.

In verbose mode, the delay in milliseconds since the previous character was received is included in the diagnostic information written to standard error. This information may be useful to determine the optimal fish_escape_delay_ms setting or learn the amount of lag introduced by tools like ssh, mosh or tmux.

fish_key_reader intentionally disables handling of many signals. To terminate fish_key_reader in --continuous mode do:

  • press Control+C twice, or
  • press Control+D twice, or
  • type exit, or
  • type quit

> fish_key_reader
Press a key:
# press up-arrow
bind \e\[A 'do something'
> fish_key_reader --verbose
Press a key:
# press alt+enter


           hex:   1B  char: \c[  (or \e)
(  0.027 ms)  hex:    D  char: \cM  (or \r)
bind \e\r 'do something'


2023, fish-shell developers

December 21, 2023 3.6