fish_key_reader - explore what characters keyboard keys send

Synopsis

fish_key_reader [OPTIONS]

Description

fish_key_reader is used to study input received from the terminal and can help with key binds. The program is interactive and works on standard input. Individual characters themselves and their hexadecimal values are displayed.

The tool will write an example bind command matching the character sequence captured to stdout. If the character sequence matches a special key name (see bind --key-names), both bind CHARS ... and bind -k KEYNAME ... usage will be shown. Additional details about the characters received, such as the delay between chars, are written to stderr.

The following options are available:

  • -c or --continuous begins a session where multiple key sequences can be inspected. By default the program exits after capturing a single key sequence.
  • -d or --debug=CATEGORY_GLOB enables debug output and specifies a glob for matching debug categories (like fish -d). Defaults to empty.
  • -D or --debug-stack-frames=DEBUG_LEVEL specify how many stack frames to display when debug messages are written. The default is zero. A value of 3 or 4 is usually sufficient to gain insight into how a given debug call was reached but you can specify a value up to 128.
  • -h or --help prints usage information.
  • -v or --version prints fish_key_reader's version and exits.

Usage Notes

The delay in milliseconds since the previous character was received is included in the diagnostic information written to stderr. 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 Ctrl-C twice, or
  • press Ctrl-D twice, or
  • type exit, or
  • type quit