zle

Define a new widget from a shell function

$ zle -N [widget_name] [function_name]

$ zle -l

$ zle -la

$ zle -D [widget_name]

$ zle -A [old_widget] [new_widget]

$ zle -R

$ zle -M "[message]"

zle [-lLaD] [widget ...]
zle -N widget [function]
zle -C widget completion-widget function
zle -R [-c] [display-string] [string ...]
zle -M string
zle -U string
zle -K keymap
zle -F [-Lw] [fd [handler]]
zle widget [-n num] [-f flag] [-Nw] [-K keymap] [-- args ...]

zle is a builtin command of zsh that controls the Zsh Line Editor, the interactive command-line editing subsystem. It manages widgets (named editing actions), keymaps, display control, and the edit buffer. When called with no arguments, it returns zero if ZLE is currently active.
ZLE activates automatically in interactive zsh sessions. It operates in multiline mode (default) or single-line mode (when the SINGLE_LINE_ZLE option is set). Special parameters like BUFFER, CURSOR, LBUFFER, and RBUFFER allow widget functions to manipulate the edit buffer directly.

-N widget [function]

Define a new user-defined widget backed by a shell function. If function is omitted, defaults to the widget name

Create a user-defined completion widget inheriting behavior from an existing builtin completion widget

List user-defined widgets. -L: format as zle commands. -a: include builtins

Delete named user-defined widgets

Create an alias; both names refer to the same widget

Redisplay the command line. Optional display-string appears in status line. -c clears completion lists

Display a message string below the command line that persists after the widget returns

Push characters onto ZLE's input stack for processing after the current widget finishes

Select the named keymap for subsequent keystrokes

Install or remove a handler for a file descriptor. -w: handler is a widget. -L: list handlers

Invalidate the current display before external output

Set flags on the current widget: yank, yankbefore, kill, vichange, nolast

ZLE is configured primarily through .zshrc using bindkey commands and zle -N widget definitions. The KEYTIMEOUT parameter (default 40, in hundredths of a second) controls how long ZLE waits for multi-character key sequences. Hook widgets like zle-line-init, zle-line-finish, and zle-keymap-select run automatically at specific events.
Example custom widget that prepends sudo:

$ prepend-sudo() {
  BUFFER="sudo $BUFFER"
  CURSOR+=5
}
zle -N prepend-sudo
bindkey '^s' prepend-sudo

ZLE provides eight built-in keymaps:
emacs -- Emacs-style editing
viins -- Vi insert mode
vicmd -- Vi command mode
viopp -- Vi operator-pending mode
visual -- Vi visual selection mode
isearch -- Incremental search mode
command -- Command name reading mode
.safe -- Immutable fallback keymap
The main keymap links to either emacs or viins depending on the EDITOR environment variable, or can be set with bindkey -e (emacs) or bindkey -v (vi).

zle is only available inside zsh and is not a POSIX command or available in bash. Widgets can only be invoked when ZLE is active in interactive mode. Widget shell functions run with stdin redirected to /dev/null. Built-in widgets have a dot-prefixed variant (e.g., .end-of-line) that remains accessible even when the widget is overridden.

ZLE is a fundamental component of zsh, the Z Shell, originally written by Paul Falstad in 1990 at Princeton University. It provides zsh with sophisticated line editing modeled after both Emacs and vi editing modes but is zsh's own independent implementation with a widget-based architecture, distinct from GNU Readline used by bash.

zsh(1), bindkey(1), vared(1)