Ivy User Manual

Table of Contents

1 Copying

Ivy manual, version 0.8.0

Ivy is an interactive interface for completion in Emacs. Emacs uses completion mechanism in a variety of contexts: code, menus, commands, variables, functions, etc. Completion entails listing, sorting, filtering, previewing, and applying actions on selected items. When active, ivy-mode completes the selection process by narrowing available choices while previewing in the minibuffer. Selecting the final candidate is either through simple keyboard character inputs or through powerful regular expressions.

Copyright (C) 2015 Free Software Foundation, Inc.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, with the Front-Cover Texts being ``A GNU Manual,'' and with the Back-Cover Texts as in (a) below. A copy of the license is included in the section entitled ``GNU Free Documentation License.''

(a) The FSF's Back-Cover Text is: ``You have the freedom to copy and modify this GNU manual.''

This manual source

2 Introduction

Ivy is for quick and easy selection from a list. When Emacs prompts for a string from a list of several possible choices, Ivy springs into action to assist in narrowing and picking the right string from a vast number of choices.

Ivy strives for minimalism, simplicity, customizability and discoverability.

Uncluttered minibuffer is minimalism. Ivy shows the completion defaults, the number of matches, and 10 candidate matches below the input line. Customize ivy-height to adjust the number of candidate matches displayed in the minibuffer.
Simplicity is about Ivy's behavior in the minibuffer. It is also about the code interface to extend Ivy's functionality. The minibuffer area behaves as close to fundamental-mode as possible. SPC inserts a space, for example, instead of being bound to the more complex minibuffer-complete-word. Ivy's code uses easy-to-examine global variables; avoids needless complications with branch-introducing custom macros.
Customizability is about being able to use different methods and interfaces of completion to tailor the selection process. For example, adding a custom display function that points to a selected candidate with >, instead of highlighting the selected candidate with the ivy-current-match face (see ivy-format-function). Or take the customization of actions, say after the candidate function is selected. RET uses counsel-describe-function to describe the function, whereas M-o d jumps to that function's definition in the code. The M-o prefix can be uniformly used with characters like d to group similar actions.
Ivy displays easily discoverable commands through the hydra facility. C-o in the minibuffer displays a hydra menu. It opens up within an expanded minibuffer area. Each menu item comes with short documentation strings and highlighted one-key completions. So discovering even seldom used keys is simply a matter of C-o in the minibuffer while in the midst of the Ivy interaction. This discoverability minimizes exiting Ivy interface for documentation look-ups.

3 Installation

Install Ivy automatically through Emacs's package manager, or manually from Ivy's development repository.

Emacs 24.3.1 is the oldest version to run Ivy. Emacs 24.5.1 is the oldest version that runs Ivy with fancy faces display.

3.1 Installing from Emacs Package Manager

M-x package-install RET ivy RET

Ivy is installed as part of ivy package, which is available from two different package archives, GNU ELPA and MELPA. For the latest stable version, use the GNU ELPA archives using the above M-x command.

For current hourly builds, use the MELPA archives. In MELPA, Ivy is split into three packages: ivy, swiper and counsel; you can simply install counsel which will bring in the other two as dependencies. See the code below for adding MELPA to the list of package archives:

(require 'package)
(add-to-list 'package-archives
             '("melpa" . "http://melpa.org/packages/"))

After this do M-x package-refresh-contents RET, followed by M-x package-install RET counsel RET.

For package manager details, see emacs#Packages.

3.2 Installing from the Git repository

Why install from Git?
  • No need to wait for MELPA's hourly builds
  • Easy to revert to previous versions
  • Contribute to Ivy's development; send patches; pull requests
Configuration steps

First clone the Swiper repository with:

cd ~/git && git clone https://github.com/abo-abo/swiper
cd swiper && make compile

Second, add these lines to the Emacs init file:

(add-to-list 'load-path "~/git/swiper/")
(require 'ivy)

Then, update the code with:

git pull

4 Getting started

First enable Ivy completion everywhere:

(ivy-mode 1)

Note: ivy-mode can be toggled on and off with M-x ivy-mode.

4.1 Basic customization

Here are some basic settings particularly useful for new Ivy users:

(setq ivy-use-virtual-buffers t)
(setq ivy-count-format "(%d/%d) ")

If you want, you can go without any customizations at all. The above settings are the most bang for the buck in terms of customization. So users that typically don't like customize a lot are advised to look at these settings first.

For more advanced customizations, refer to M-x describe-variable documentation.

5 Key bindings

5.1 Global key bindings

The recommended key bindings are:

Ivy-based interface to standard commands
(global-set-key (kbd "C-s") 'swiper)
(global-set-key (kbd "M-x") 'counsel-M-x)
(global-set-key (kbd "C-x C-f") 'counsel-find-file)
(global-set-key (kbd "<f1> f") 'counsel-describe-function)
(global-set-key (kbd "<f1> v") 'counsel-describe-variable)
(global-set-key (kbd "<f1> l") 'counsel-find-library)
(global-set-key (kbd "<f2> i") 'counsel-info-lookup-symbol)
(global-set-key (kbd "<f2> u") 'counsel-unicode-char)
Ivy-based interface to shell and system tools
(global-set-key (kbd "C-c g") 'counsel-git)
(global-set-key (kbd "C-c j") 'counsel-git-grep)
(global-set-key (kbd "C-c k") 'counsel-ag)
(global-set-key (kbd "C-x l") 'counsel-locate)
(global-set-key (kbd "C-S-o") 'counsel-rhythmbox)
Ivy-resume and other commands

ivy-resume resumes the last Ivy-based completion.

(global-set-key (kbd "C-c C-r") 'ivy-resume)

5.2 Minibuffer key bindings

Ivy includes several minibuffer bindings, which are defined in the ivy-minibuffer-map keymap variable. The most frequently used ones are described here.

swiper or counsel-M-x add more key bindings through the keymap argument to ivy-read. These keys, also active in the minibuffer, are described under their respective commands.

A key feature of ivy-minibuffer-map is its full editing capability where the familiar C-a, C-f, M-d, M-DEL, M-b, M-w, C-k, C-y key bindings work the same as in fundamental-mode.

5.2.1 Key bindings for navigation

  • C-n (ivy-next-line) selects the next candidate
  • C-p (ivy-previous-line) selects the previous candidate
  • M-< (ivy-beginning-of-buffer) selects the first candidate
  • M-> (ivy-end-of-buffer) selects the last candidate
  • C-v (ivy-scroll-up-command) scrolls up by ivy-height lines
  • M-v (ivy-scroll-down-command) scrolls down by ivy-height lines
User Option ivy-wrap

Specifies the wrap-around behavior for C-n and C-p. When ivy-wrap is set to t, ivy-next-line and ivy-previous-line will cycle past the last and the first candidates respectively.

Warp-around behavior is off by default.

User Option ivy-height

Use this option to adjust the minibuffer height, which also affects scroll size when using C-v and M-v key bindings.

ivy-height is 10 lines by default.

5.2.2 Key bindings for single selection, action, then exit minibuffer

Ivy can offer several actions from which to choose which action to run. This "calling an action" operates on the selected candidate. For example, when viewing a list of files, one action could open it for editing, one to view it, another to invoke a special function, and so on. Custom actions can be added to this interface. The precise action to call on the selected candidate can be delayed until after the narrowing is completed. No need to exit the interface if unsure which action to run. This delayed flexibility and customization of actions extends usability of lists in Emacs.

C-m or RET (ivy-done)
Calls the default action and then exits the minibuffer.
M-o (ivy-dispatching-done)
Presents valid actions from which to choose. When only one action is available, there is no difference between M-o and C-m.
C-j (ivy-alt-done)
When completing file names, selects the current directory candidate and starts a new completion session there. Otherwise, it is the same as ivy-done.
TAB (ivy-partial-or-done)

Attempts partial completion, extending current input as much as possible. TAB TAB is the same as C-j (ivy-alt-done).

Example ERT test:

 (equal (ivy-with
           (ivy-read "Test: " '("can do" "can't, sorry" "other"))
         "c <tab>")
C-M-j (ivy-immediate-done)

Exits with the current input instead of the current candidate (like other commands).

This is useful e.g. when you call find-file to create a new file, but the desired name matches an existing file. In that case, using C-j would select that existing file, which isn't what you want - use this command instead.

C-' (ivy-avy)
Uses avy to select one of the candidates on the current candidate page. This can often be faster than multiple C-n or C-p keystrokes followed by C-m.

5.2.3 Key bindings for multiple selections and actions, keep minibuffer open

For repeatedly applying multiple actions or acting on multiple candidates, Ivy does not close the minibuffer between commands. It keeps the minibuffer open for applying subsequent actions.

Adding an extra meta key to the normal key chord invokes the special version of the regular commands that enables applying multiple actions.

C-M-m (ivy-call)

Is the non-exiting version of C-m (ivy-done).

Instead of closing the minibuffer, C-M-m allows selecting another candidate or another action. For example, C-M-m on functions list invokes describe-function. When combined with C-n, function descriptions can be invoked quickly in succession.

C-M-o (ivy-dispatching-call)

Is the non-exiting version of M-o (ivy-dispatching-done).

For example, during the counsel-rhythmbox completion, press C-M-o e to en-queue the selected candidate, followed by C-n C-m to play the next candidate - the current action reverts to the default one after C-M-o.

C-M-n (ivy-next-line-and-call)

Combines C-n and C-M-m. Applies an action and moves to next line.

Comes in handy when opening multiple files from counsel-find-file, counsel-git-grep, counsel-ag, counsel-rg, or counsel-locate lists. Just hold C-M-n for rapid-fire default action on each successive element of the list.

C-M-p (ivy-previous-line-and-call)

Combines C-p and C-M-m.

Similar to the above except it moves through the list in the other direction.


Recalls the state of the completion session just before its last exit.

Useful after an accidental C-m (ivy-done).

5.2.4 Key bindings that alter the minibuffer input

M-n (ivy-next-history-element)

Cycles forward through the Ivy command history.

Ivy updates an internal history list after each action. When this history list is empty, M-n inserts symbol (or URL) at point into the minibuffer.

M-p (ivy-previous-history-element)
Cycles forward through the Ivy command history.
M-i (ivy-insert-current)

Inserts the current candidate into the minibuffer.

Useful for copying and renaming files, for example: M-i to insert the original file name string, edit it, and then C-m to complete the renaming.

M-j (ivy-yank-word)

Inserts the sub-word at point into the minibuffer.

This is similar to C-s C-w with isearch. Ivy reserves C-w for kill-region.

S-SPC (ivy-restrict-to-matches)

Deletes the current input, and resets the candidates list to the currently restricted matches.

This is how Ivy provides narrowing in successive tiers.

C-r (ivy-reverse-i-search)

Starts a recursive completion session through the command's history.

This works just like C-r at the bash command prompt, where the completion candidates are the history items. Upon completion, the selected candidate string is inserted into the minibuffer.

5.2.5 Other key bindings

M-w (ivy-kill-ring-save)

Copies selected candidates to the kill ring.

Copies the region if the region is active.

5.2.6 Hydra in the minibuffer

C-o (hydra-ivy/body)
Invokes the hydra menu with short key bindings.

When Hydra is active, minibuffer editing is disabled and menus display short aliases:

Short Normal Command name
o C-g keyboard-escape-quit
j C-n ivy-next-line
k C-p ivy-previous-line
h M-< ivy-beginning-of-buffer
l M-> ivy-end-of-buffer
d C-m ivy-done
f C-j ivy-alt-done
g C-M-m ivy-call
u C-c C-o ivy-occur

Hydra reduces key strokes, for example: C-n C-n C-n C-n is C-o jjjj in Hydra.

Hydra menu offers these additioanl bindings:

c (ivy-toggle-calling)
Toggle calling the action after each candidate change. It modifies j to jg, k to kg etc.
m (ivy-toggle-fuzzy)
Toggle the current regexp matcher.
> (ivy-minibuffer-grow)
Increase ivy-height for the current minibuffer.
< (ivy-minibuffer-shrink)
Decrease ivy-height for the current minibuffer.
w (ivy-prev-action)
Select the previous action.
s (ivy-next-action)
Select the next action.
a (ivy-read-action)
Use a menu to select an action.
C (ivy-toggle-case-fold)
Toggle case folding (match both upper and lower case characters for lower case input).

5.2.7 Saving the current completion session to a buffer

C-c C-o (ivy-occur)
Saves the current candidates to a new buffer and exits completion.

The new buffer is read-only and has a few useful bindings defined.

RET or j (ivy-occur-press)
Call the current action on the selected candidate.
mouse-1 (ivy-occur-click)
Call the current action on the selected candidate.
j (next-line)
Move to next line.
k (previous-line)
Move to previous line.
a (ivy-occur-read-action)
Read an action and make it current for this buffer.
o (ivy-occur-dispatch)
Read an action and call it on the selected candidate.
q (quit-window)
Bury the current buffer.

Ivy has no limit on the number of active buffers like these.

Ivy takes care of naming buffers uniquely by constructing descriptive names. For example: *ivy-occur counsel-describe-variable "function$*.

6 Completion Styles

Ivy's completion functions rely on a regex builder - a function that transforms a string input to a string regex. All current candidates simply have to match this regex. Each collection can be assigned its own regex builder by customizing ivy-re-builders-alist.

The keys of this alist are collection names, and the values are one of the following:

  • ivy--regex
  • ivy--regex-plus
  • ivy--regex-ignore-order
  • ivy--regex-fuzzy
  • regexp-quote

A catch-all key, t, applies to all collections that don't have their own key.

The default is:

(setq ivy-re-builders-alist
      '((t . ivy--regex-plus)))

This example shows a custom regex builder assigned to file name completion:

(setq ivy-re-builders-alist
      '((read-file-name-internal . ivy--regex-fuzzy)
        (t . ivy--regex-plus)))

Here, read-file-name-internal is a function that is passed as the second argument to completing-read for file name completion.

The regex builder resolves as follows (in order of priority):

  1. re-builder argument passed to ivy-read.
  2. collection argument passed to ivy-read is a function and has an entry on ivy-re-builders-alist.
  3. caller argument passed to ivy-read has an entry on ivy-re-builders-alist.
  4. this-command has an entry on ivy-re-builders-alist.
  5. t has an entry on ivy-re-builders-alist.
  6. ivy--regex.

6.1 ivy–regex-plus

ivy--regex-plus is Ivy's default completion method.

ivy--regex-plus matches by splitting the input by spaces and rebuilding it into a regex.

As the search string is typed in Ivy's minibuffer, it is transformed into valid regex syntax. If the string is "for example", it is transformed into


which in regex terminology matches "for" followed by a wild card and then "example". Note how Ivy uses the space character to build wild cards. To match a literal white space, use an extra space. So to match one space type two spaces, to match two spaces type three spaces, and so on.

As Ivy transforms typed characters into regex strings, it provides an intuitive feedback through font highlights.

Ivy supports regexp negation with "!". For example, "define key ! ivy quit" first selects everything matching "define.*key", then removes everything matching "ivy", and finally removes everything matching "quit". What remains is the final result set of the negation regexp.

Since Ivy treats minibuffer input as a regexp, the standard regexp identifiers work: "^", "$", "\b" or "[a-z]". The exceptions are spaces, which translate to ".*", and "!" that signal the beginning of a negation group.

6.2 ivy–regex-ignore-order

ivy--regex-ignore-order ignores the order of regexp tokens when searching for matching candidates. For instance, the input "for example" will match "example test for".

6.3 ivy–regex-fuzzy

ivy--regex-fuzzy splits each character with a wild card. Searching for "for" returns all "f.*o.*r" matches, resulting in a large number of hits. Yet some searches need these extra hits. Ivy sorts such large lists using flx package's scoring mechanism, if it's installed.

C-o m toggles the current regexp builder.

7 Customization

7.1 Faces

Highlights the currently selected candidate.
Highlights the background of the match.
Highlights the first (modulo 3) matched group.
Highlights the second (modulo 3) matched group.
Highlights the third (modulo 3) matched group.

Highlights the "(confirm)" part of the prompt.

When confirm-nonexistent-file-or-buffer set to t, then confirming non-existent files in ivy-mode requires an additional RET.

The confirmation prompt will use this face.

For example:

(setq confirm-nonexistent-file-or-buffer t)

Then call find-file, enter "eldorado" and press RET - the prompt will be appended with "(confirm)". Press RET once more to confirm, or any key to continue the completion.


Highlights the "(match required)" part of the prompt.

When completions have to match available candidates and cannot take random input, the "(match required)" prompt signals this constraint.

For example, call describe-variable, enter "waldo" and press RET - "(match required)" is prompted. Press any key for the prompt to disappear.

Highlights directories when completing file names.
Highlights remote files when completing file names.

Highlights virtual buffers when completing buffer names.

Virtual buffers correspond to bookmarks and recent files list, recentf.

Enable virtual buffers with:

(setq ivy-use-virtual-buffers t)

7.2 Defcustoms

User Option ivy-count-format

A string that specifies display of number of candidates and current candidate, if one exists.

The number of matching candidates by default is shown as a right- padded integer value.

To disable showing the number of candidates:

(setq ivy-count-format "")

To also display the current candidate:

(setq ivy-count-format "(%d/%d) ")

The format-style switches this variable uses are described in the format documentation.

User Option ivy-display-style

Specifies highlighting candidates in the minibuffer.

The default setting is 'fancy and valid only in Emacs versions 24.5 or newer.

Set ivy-display-style to nil for a plain minibuffer.

User Option ivy-on-del-error-function

Specify what when DEL (ivy-backward-delete-char) throws.

The default behavior is to quit the completion after DEL – a handy key to invoke after mistakenly triggering a completion.

7.3 Actions

7.3.1 What are actions?

An action is a function that is called after you select a candidate during completion. This function takes a single string argument, which is the selected candidate.

Window context when calling an action

Currently, the action is executed in the minibuffer window context. This means e.g. that if you call insert the text will be inserted into the minibuffer.

If you want to execute the action in the initial window from which the completion started, use the with-ivy-window wrapper macro.

(defun ivy-insert-action (x)
    (insert x)))

7.3.2 How can different actions be called?

  • C-m (ivy-done) calls the current action.
  • M-o (ivy-dispatching-done) presents available actions for selection, calls it after selection, and then exits.
  • C-M-o (ivy-dispatching-call) presents available actions for selection, calls it after selection, and then does not exit.

7.3.3 How to modify the actions list?

Currently, you can append any amount of your own actions to the default list of actions. This can be done either for a specific command, or for all commands at once.

Usually, the command has only one default action. The convention is to use single letters when selecting a command, and the letter o is designated for the default command. This way, M-o o should be always equivalent to C-m.

7.3.4 Example - add two actions to each command

The first action inserts the current candidate into the Ivy window - the window from which ivy-read was called.

The second action copies the current candidate to the kill ring.

(defun ivy-yank-action (x)
  (kill-new x))

(defun ivy-copy-to-buffer-action (x)
    (insert x)))

 '(("i" ivy-copy-to-buffer-action "insert")
   ("y" ivy-yank-action "yank")))

Then in any completion session, M-o y invokes ivy-yank-action, and M-o i invokes ivy-copy-to-buffer-action. How to undo adding the two actions

Since ivy-set-actions modifies the internal dictionary with new data, set the extra actions list to nil by assigning nil value to the t key as follows:

(ivy-set-actions t nil) How to add actions to a specific command

Use the command name as the key:

 '(("i" ivy-copy-to-buffer-action "insert")
   ("y" ivy-yank-action "yank")))

7.3.5 Example - define a new command with several actions

(defun my-action-1 (x)
  (message "action-1: %s" x))

(defun my-action-2 (x)
  (message "action-2: %s" x))

(defun my-action-3 (x)
  (message "action-3: %s" x))

(defun my-command-with-3-actions ()
  (ivy-read "test: " '("foo" "bar" "baz")
            :action '(1
                      ("o" my-action-1 "action 1")
                      ("j" my-action-2 "action 2")
                      ("k" my-action-3 "action 3"))))

The number 1 above is the index of the default action. Each action has its own string description for easy selection. Test the above function with ivy-occur

To examine each action with each candidate in a key-efficient way, try:

  • Call my-command-with-3-actions
  • Press C-c C-o to close the completion window and move to an ivy-occur buffer
  • Press kkk to move to the first candidate, since the point is most likely at the end of the buffer
  • Press oo to call the first action
  • Press oj and ok to call the second and the third actions
  • Press j to move to the next candidate
  • Press oo, oj, ok
  • Press j to move to the next candidate
  • and so on…

7.4 Packages

org-mode versions 8.3.3 or later obey completing-read-function (which ivy-mode sets). Try refiling headings with similar names to appreciate ivy-mode.

Magit requires this setting for ivy completion:

(setq magit-completing-read-function 'ivy-completing-read)
It uses ivy by default if Ivy is installed.

Projectile requires this setting for ivy completion:

(setq projectile-completion-system 'ivy)

Helm-make requires this setting for ivy completion.

(setq helm-make-completion-method 'ivy)

8 Commands

8.1 File Name Completion

Since file name completion is ubiquitous, Ivy provides extra bindings that work here:

C-j (ivy-alt-done)

On a directory, restarts completion from that directory.

On a file or ./, exit completion with the selected candidate.

DEL (ivy-backward-delete-char)
Restart the completion in the parent directory if current input is empty.
// (self-insert-command)
Switch to the root directory.
~ (self-insert-command)
Switch to the home directory.
/ (self-insert-command)
If the current input matches an existing directory name exactly, switch the completion to that directory.
M-q (ivy-toggle-regexp-quote)

Toggle between input as regexp or not.

Switch to matching literally since file names include ., which is for matching any char in regexp mode.

User Option ivy-extra-directories

Decide if you want to see ../ and ./ during file name completion.

Reason to remove: ../ is the same as DEL.

Reason not to remove: navigate anywhere with only C-n, C-p and C-j.

Likewise, ./ can be removed.


From any directory, with the empty input, inputting /ssh: and pressing C-j (or RET, which is the same thing) completes for host and user names.

For /ssh:user@ input, completes the domain name.

C-i works in a similar way to the default completion.

You can also get sudo access for the current directory by inputting /sudo:: RET. Using /sudo: (i.e. single colon instead of double) will result in a completion session for the desired user.

File history works the same with M-p, M-n, and C-r, but uses a custom code for file name completion that cycles through files previously opened. It also works with TRAMP files.

8.2 Buffer Name Completion

User Option ivy-use-virtual-buffers

When non-nil, add recentf-mode and bookmarks to ivy-switch-buffer completion candidates.

Adding this to Emacs init file:

(setq ivy-use-virtual-buffers t)

will add additional virtual buffers to the buffers list for recent files. Selecting such virtual buffers, which are highlighted with ivy-virtual face, will open the corresponding file.

8.3 Counsel commands

The main advantages of counsel- functions over their basic equivalents in ivy-mode are:

  1. Multi-actions and non-exiting actions work.
  2. ivy-resume can resume the last completion session.
  3. Customize ivy-set-actions, ivy-re-builders-alist.
  4. Customize individual keymaps, such as counsel-describe-map, counsel-git-grep-map, or counsel-find-file-map, instead of customizing ivy-minibuffer-map that applies to all completion sessions.


The main (and only) entry point is the ivy-read function. It takes two required arguments and many optional arguments that can be passed by a key. The optional :action argument is highly recommended for features such as multi-actions, non-exiting actions, ivy-occur and ivy-resume.

9.1 Required arguments for ivy-read


A format string normally ending in a colon and a space.

%d anywhere in the string is replaced by the current number of matching candidates. To use a literal % character, escape it as %%. See also ivy-count-format.


Either a list of strings, a function, an alist or a hash table.

If a function, then it has to be compatible with all-completions.

9.2 Optional arguments for ivy-read

Is a function to filter the initial collection. It has to be compatible with all-completions. Tip: most of the time, it's simpler to just apply this filter to the collection argument itself, e.g. (cl-remove-if-not predicate collection).
When set to a non-nil value, input must match one of the candidates. Custom input is not accepted.

This string argument is included for compatibility with completing-read, which inserts it into the minibuffer.

It's recommended to use the preselect argument instead of this.

Name of the symbol to store history. See completing-read.

When set to a string value, select the first candidate matching this value.

When set to an integer value, select the candidate with that index value.

Every time the input becomes empty, the item corresponding to to preselect is selected.

A keymap to be composed with ivy-minibuffer-map. This keymap has priority over ivy-minibuffer-map and can be modified at any later stage.
Is the function called each time the current candidate changes. This function takes no arguments and is called in the minibuffer's post-command-hook. See swiper for an example usage.
When non-nil, use ivy-sort-functions-alist to sort the collection as long as the collection is not larger than ivy-sort-max-size.
Is the function to call after selection. It takes a string argument.
Is the function to call before exiting completion. It takes no arguments. This function is called even if the completion is interrupted with C-g. See swiper for an example usage.
Is a function that takes a string and returns a valid regex. See Completion Styles for details.
Is a function that takes a regex string and a list of strings and returns a list of strings matching the regex. Any ordinary Emacs matching function will suffice, yet finely tuned matching functions can be used. See counsel-find-file for an example usage.
When non-nil, collection will be used to dynamically generate the candidates each time the input changes, instead of being used once statically with all-completions to generate a list of strings. See counsel-locate for an example usage.
Is a symbol that uniquely identifies the function that called ivy-read, which may be useful for further customizations.

9.3 Example - counsel-describe-function

This is a typical example of a function with a non-async collection, which is a collection where all the strings in the collection are known prior to any input from the user.

Only the first two arguments (along with action) are essential - the rest of the arguments are for fine-tuning, and could be omitted.

The action argument could also be omitted - but then ivy-read would do nothing except returning the string result, which you could later use yourself. However, it's recommended that you use the action argument.

(defun counsel-describe-function ()
  "Forward to `describe-function'."
  (ivy-read "Describe function: "
            (let (cands)
               (lambda (x)
                 (when (fboundp x)
                   (push (symbol-name x) cands))))
            :keymap counsel-describe-map
            :preselect (counsel-symbol-at-point)
            :history 'counsel-describe-symbol-history
            :require-match t
            :sort t
            :action (lambda (x)
                       (intern x)))
            :caller 'counsel-describe-function))

Here are the interesting features of the above function, in the order that they appear:

  • The prompt argument is a simple string ending in ": ".
  • The collection argument evaluates to a (large) list of strings.
  • The keymap argument is for a custom keymap to supplement ivy-minibuffer-map.
  • The preselect is provided by counsel-symbol-at-point, which returns a symbol near the point. Ivy then selects the first candidate from the collection that matches this symbol. To select this pre-selected candidate, a RET will suffice. No further user input is necessary.
  • The history argument is for keeping the history of this command separate from the common history in ivy-history.
  • The require-match is set to t since it doesn't make sense to call describe-function on an un-interned symbol.
  • The sort argument is set to t so choosing between similar candidates becomes easier. Sometimes, the collection size will exceed ivy-sort-max-size, which is 30000 by default. In that case the sorting will not happen to avoid delays.

    Adjust this variable to choose between sorting time and completion start-up time.

  • The action argument calls describe-function on the interned selected candidate.
  • The caller argument identifies this completion session. This is important, since with the collection being a list of strings and not a function name, the only other way for ivy-read to identify "who's calling" and to apply the appropriate customizations is to examine this-command. But this-command would be modified if another command called counsel-describe-function.

9.4 Example - counsel-locate

This is a typical example of a function with an async collection. Since the collection function cannot pre-compute all the locatable files in memory within reasonable limits (time or memory), it relies on user input to filter the universe of possible candidates to a manageable size while also continuing to search asynchronously for possible candidates. Both the filtering and searching continues with each character change of the input with rapid updates to the collection presented without idle waiting times. This live update will continue as long as there are likely candidates. Eventually updates to the minibuffer will stop after user input, filtering, and searching have exhausted looking for possible candidates.

Async collections suit long-running shell commands, such as locate. With each new input, a new process starts while the old process is killed. The collection is refreshed anew with each new process. Meanwhile the user can provide more input characters (for further narrowing) or select a candidate from the visible collection.

(defun counsel-locate-function (str)
  (if (< (length str) 3)
      (counsel-more-chars 3)
     (format "locate %s '%s'"
             (mapconcat #'identity counsel-locate-options " ")
              (ivy--regex str))))
    '("" "working...")))

(defun counsel-locate (&optional initial-input)
  "Call the \"locate\" shell command.
INITIAL-INPUT can be given as the initial minibuffer input."
  (ivy-read "Locate: " #'counsel-locate-function
            :initial-input initial-input
            :dynamic-collection t
            :history 'counsel-locate-history
            :action (lambda (file)
                        (when file
                          (find-file file))))
            :unwind #'counsel-delete-process
            :caller 'counsel-locate))

Here are the interesting features of the above functions, in the order that they appear:

  • counsel-locate-function takes a string argument and returns a list of strings. Note that it's not compatible with all-completions, but since we're not using that here, might as well use one argument instead of three.
  • counsel-more-chars is a simple function that returns e.g. '("2 chars more") asking the user for more input.
  • counsel--async-command is a very easy API simplification that takes a single string argument suitable for shell-command-to-string. So you could prototype your function as non-async using shell-command-to-string and split-string to produce a collection, then decide that you want async and simply swap in counsel--async-command.
  • counsel-locate is an interactive function with an optional initial-input.
  • #'counsel-locate-function is passed as the collection argument.
  • dynamic-collection is set to t, since this is an async collection.
  • action argument uses with-ivy-window wrapper, since we want to open the selected file in the same window from which counsel-locate was called.
  • unwind argument is set to #'counsel-delete-process: when we press C-g we want to kill the running process created by counsel--async-command.
  • caller argument identifies this command for easier customization.

9.5 Example - ivy-read-with-extra-properties

This is another example to show how to associate additional values to each displayed strings.

(defun find-candidates-function (str pred _)
  (let ((props '(1 2))
        (strs '("foo" "foo2")))
    (cl-mapcar (lambda (s p) (propertize s 'property p))

(defun find-candidates ()
  (ivy-read "Find symbols: "
            :action (lambda (x)
                      (message "Value: %s" (get-text-property 0 'property x)

Here are the interesting features of the above function:

  • find-candidates-function builds up a list of strings and associates "foo" with the value 1 and "foo2" with 2.
  • find-candidates is an interactive function.
  • #'find-candidates is passed as the collection argument.
  • action gets passed the selected string with the associated value. It then retrieves that value and displays it.

10 Variable Index

11 Keystroke Index