Life is short, skim!

We spend so much of our time navigating through files, lines, and commands. That's where Skim comes in! It's a powerful fuzzy finder designed to make your workflow faster and more efficient.

Skim provides a single executable called sk. Think of it as a smarter alternative to tools like grep - once you try it, you'll wonder how you ever lived without it!

Table of contents

• Installation
  • Package Managers
  • Manually
• Usage
  • As Vim plugin
  • As filter
  • As Interactive Interface
  • Shell Bindings
  • Key Bindings
  • Search Syntax
  • exit code
• Tools compatible with skim
  • fzf-lua neovim plugin
  • nu_plugin_skim
• Customization
  • Keymap
  • Sort Criteria
  • Color Scheme
  • Misc
• Advanced Topics
  • Interactive mode
    • How does it work?
  • Executing external programs
  • Algorithms
  • Preview Window
    • How does it work?
  • Fields support
  • Use as a library
• FAQ
  • How to ignore files?
  • Some files are not shown in Vim plugin
• Differences from fzf
• How to contribute
• Troubleshooting
  • No line feed issues with nix, FreeBSD, termux

Installation

The skim project contains several components:

1. sk executable - the core program
2. Vim/Nvim plugin - to call sk inside Vim/Nvim. Check skim.vim for Vim support.

Package Managers

OS	Package Manager	Command
macOS	Homebrew	brew install sk
macOS	MacPorts	sudo port install skim
Alpine	apk	apk add skim
Arch	pacman	pacman -S skim
Fedora	COPR	see below
Gentoo	Portage	emerge --ask app-misc/skim
Guix	guix	guix install skim
Void	XBPS	xbps-install -S skim

Fedora

Up to date Fedora packages are provided via an unofficial community-maintained COPR repository.

sudo dnf copr enable sisyphus1813/skim
sudo dnf install skim

Manually

Any of the following applies:

• Using the install script:

  # Always check the content of the script before running it !
  $ curl --proto '=https' --tlsv1.2 -LsSf https://github.com/skim-rs/skim/releases/latest/download/skim-installer.sh | sh
  

• Using Binary: Simply download the sk executable directly.
• Install from crates.io: cargo install skim
• Build Manually:

  $ git clone --depth 1 git@github.com:skim-rs/skim.git ~/.skim
  $ cd ~/.skim
  $ cargo build --release
  $ # Add the resulting `target/release/sk` executable to your PATH
  

You will then have access to:

• The man page, which you can either write to the correct path or run man --local-file <(sk --man)
• The shell completions (and optional keybinds), using source <(sk --shell \<shell> \[--shell-bindings]), see below for details

Usage

Skim can be used either as a general filter (similar to grep) or as an interactive interface for running commands.

As Vim plugin (on neovim, checkout fzf-lua with the skim profile)

Via vim-plug (recommended):

Install skim, then :

Plug 'skim-rs/skim'

As filter

Here are some examples to get you started:

# directly invoke skim
sk

# Or pipe some input to it (press TAB key to select multiple items when -m is enabled)
vim $(find . -name "*.rs" | sk -m)

This last command lets you select files with the ".rs" extension and opens your selections in Vim - a great time-saver for developers!

As Interactive Interface

skim can invoke other commands dynamically. Normally you would want to integrate it with grep, ack, ag, or rg for searching contents in a project directory:

# works with grep
sk --ansi -i -c 'grep -rI --color=always --line-number {q} .'
# works with ack
sk --ansi -i -c 'ack --color {q}'
# works with ag
sk --ansi -i -c 'ag --color {q}'
# works with rg
sk --ansi -i -c 'rg --color=always --line-number {q}'

Note

: In these examples, {q} will be literally expanded to the current input query (wrapped in single quotes). This means these examples will search for the exact query string, not fuzzily. For fuzzy searching, pipe the command output into sk without using interactive mode.

Shell Bindings

Bindings for Fish, Bash and Zsh are available in the shell directory:

• completion.{shell} contains the completion scripts for sk cli usage
• key-bindings.{shell} contains key-binds and shell integrations:
  • ctrl-t to select a file through sk
  • ctrl-r to select an history entry through sk
  • alt-c to cd into a directory selected through sk
  • (not available in fish) ** to complete file paths, for example ls **<tab> will show a sk widget to select a folder

To enable these features, source the key-bindings.{shell} file and set up completions according to your shell's documentation or see below.

Shell Completions

You can generate shell completions for your preferred shell using the --shell flag with one of the supported shells: bash, zsh, fish, powershell, or elvish:

Note: While PowerShell completions are supported, Windows is not supported for now.

Option 1: Source directly in your current shell session

# For bash
source <(sk --shell bash)

# For zsh
source <(sk --shell zsh)

# For fish
sk --shell fish | source

Option 2: Save to a file to be loaded automatically on shell startup

# For bash, add to ~/.bashrc
echo 'source <(sk --shell bash)' >> ~/.bashrc  # Or save to ~/.bash_completion

# For zsh, add to ~/.zshrc
sk --shell zsh > ~/.zfunc/_sk  # Create ~/.zfunc directory and add to fpath in ~/.zshrc

# For fish, add to ~/.config/fish/completions/
sk --shell fish > ~/.config/fish/completions/sk.fish

Key Bindings

Some commonly used key bindings:

Key	Action
Enter	Accept (select current one and quit)
ESC/Ctrl-G	Abort
Ctrl-P/Up	Move cursor up
Ctrl-N/Down	Move cursor Down
TAB	Toggle selection and move down (with -m)
Shift-TAB	Toggle selection and move up (with -m)

For a complete list of key bindings, refer to the man page (man sk).

Search Syntax

skim borrows fzf's syntax for matching items:

Token	Match type	Description
text	fuzzy-match	items that match text
^music	prefix-exact-match	items that start with music
.mp3$	suffix-exact-match	items that end with .mp3
'wild	exact-match (quoted)	items that include wild
!fire	inverse-exact-match	items that do not include fire
!.mp3$	inverse-suffix-exact-match	items that do not end with .mp3

skim also supports the combination of tokens.

• Whitespace has the meaning of AND. With the term src main, skim will search for items that match both src and main.

• | means OR (note the spaces around |). With the term .md$ | .markdown$, skim will search for items ends with either .md or .markdown.

• OR has higher precedence. For example, readme .md$ | .markdown$ is interpreted as readme AND (.md$ OR .markdown$).

• When using the --split-match option, each part around spaces or | will be matched in a split way:

  • If the option's value (defaulting to :) is absent from the query, do a normal match
  • If it is present, match everything before to everything before it in the items, and everything after it (including potential other occurences of the delimiter) to the part after it in the items. This is particularly useful when piping in input from rg to match on both file name and content.

If you prefer using regular expressions, skim offers a regex mode:

sk --regex

You can switch to regex mode dynamically by pressing Ctrl-R (Rotate Mode).

exit code

Exit Code	Meaning
0	Exited normally
1	No Match found
130	Aborted by Ctrl-C/Ctrl-G/ESC/etc...

Tools compatible with skim

These tools are or aim to be compatible with skim:

fzf-lua neovim plugin

A neovim plugin allowing fzf and skim to be used in a to navigate your code.

Install it with your package manager, following the README. For instance, with lazy.nvim:

{
  "ibhagwan/fzf-lua",
  -- enable `sk` support instead of the default `fzf`
  opts = {'skim'}
}

nu_plugin_skim

A nushell plugin to allow for better interaction between skim and nushell.

Following the instruction in the plugin's README, you can install it with cargo:

cargo install nu_plugin_skim
plugin add ~/.cargo/bin/nu_plugin_skim

sqlite extension

An sqlite loadable module which enables a skim_score function in SQL queries.

Customization

The doc here is only a preview, please check the man page (man sk) for a full list of options.

Keymap

Specify the bindings with comma separated pairs (no space allowed). For example:

sk --bind 'alt-a:select-all,alt-d:deselect-all'

Additionally, use + to concatenate actions, such as execute-silent(echo {} | pbcopy)+abort.

See the KEY BINDINGS section of the man page for details.

Sort Criteria

There are five sort keys for results: score, index, begin, end, length. You can specify how the records are sorted by sk --tiebreak score,index,-begin or any other order you want.

Color Scheme

You probably have your own aesthetic preferences! Fortunately, you aren't limited to the default appearance - Skim supports comprehensive customization of its color scheme.

--color=[BASE_SCHEME][,COLOR:ANSI]

Skim also respects the NO_COLOR environment variable. Set it to anything and sk (and many other terminal apps) will disable all colored output. See no-color.org for more details.

Available Base Color Schemes

Skim comes with several built-in color schemes that you can use as a starting point:

sk --color=dark      # Default dark theme (256 colors)
sk --color=light     # Light theme (256 colors)
sk --color=16        # Simple 16-color theme
sk --color=bw        # Minimal black & white theme (no colors, just styles)
sk --color=none      # Minimal black & white theme (no colors, no styles)
sk --color=molokai   # Molokai-inspired theme (256 colors)

Customizing Colors

You can customize individual UI elements by specifying color values after the base scheme:

sk --color=light,fg:232,bg:255,current_bg:116,info:27

Colors can be specified in several ways:

• ANSI colors (0-255): sk --color=fg:232,bg:255
• RGB hex values: sk --color=fg:#FF0000 (red text)

Available Color Customization Options

The following UI elements can be customized:

Element	Description	Example
fg	Normal text foreground color	--color=fg:232
bg	Normal text background color	--color=bg:255
matched	Matched text in search results	--color=matched:108
matched_bg	Background of matched text	--color=matched_bg:0
current	Current line foreground color	--color=current:254
current_bg	Current line background color	--color=current_bg:236
current_match	Matched text in current line	--color=current_match:151
current_match_bg	Background of matched text in current line	--color=current_match_bg:236
spinner	Progress indicator color	--color=spinner:148
info	Information line color	--color=info:144
prompt	Prompt color	--color=prompt:110
cursor	Cursor color	--color=cursor:161
selected	Selected item marker color	--color=selected:168
header	Header text color	--color=header:109
border	Border color for preview/layout	--color=border:59

Examples

# Use light theme but change the current line background
sk --color=light,current_bg:24

# Custom theme with multiple colors
sk --color=dark,matched:#00FF00,current:#FFFFFF,current_bg:#000080

# High contrast theme
sk --color=fg:232,bg:255,matched:160,current:255,current_bg:20

For more details, check the man page (man sk).

Misc

• --ansi: to parse ANSI color codes (e.g., \e[32mABC) of the data source
• --regex: use the query as regular expression to match the data source

Advanced Topics

Interactive mode

In interactive mode, you can invoke a command dynamically. Try it out:

sk --ansi -i -c 'rg --color=always --line-number {q}'

How does it work?

• Skim accepts two kinds of sources: Command output or piped input
• Skim has two kinds of prompts: A query prompt to specify the query pattern and a command prompt to specify the "arguments" of the command
• -c is used to specify the command to execute and defaults to SKIM_DEFAULT_COMMAND
• -i tells skim to open command prompt on startup, which will show c> by default.

To further narrow down the results returned by the command, press Ctrl-Q to toggle interactive mode.

Executing external programs

You can configure key bindings to start external processes without leaving Skim (execute, execute-silent).

# Press F1 to open the file with less without leaving skim
# Press CTRL-Y to copy the line to clipboard and aborts skim (requires pbcopy)
sk --bind 'f1:execute(less -f {}),ctrl-y:execute-silent(echo {} | pbcopy)+abort'

Algorithms

Skim offers multiple algorithms, check the help or manpage for an exhaustive list. Among them are:

• skim_v2, the default algorithm, loosely based on fzf's algorithm
• frizbee(crate, the typo-resistant algorithm used in the blink.cmp neovim plugin
• fzy, based on fzy's algorithm expanded for basic typo-resistance
• arinae, skim's newest algorithm, designed in-house with typo-resistance in mind, expanding on all the above to make typo-resistant matching feel more natural while keeping the per-item performance up to the best standards

Preview Window

This is a great feature of fzf that skim borrows. For example, we use 'ag' to find the matched lines, and once we narrow down to the target lines, we want to finally decide which lines to pick by checking the context around the line. grep and ag have the option --context, and skim can make use of --context for a better preview window. For example:

sk --ansi -i -c 'ag --color {q}' --preview "preview.sh {}"

(Note that preview.sh is a script to print the context given filename:lines:columns)

You get things like this:

How does it work?

If the preview command is given by the --preview option, skim will replace the {} with the current highlighted line surrounded by single quotes, call the command to get the output, and print the output on the preview window.

Sometimes you don't need the whole line for invoking the command. In this case you can use {}, {1..}, {..3} or {1..5} to select the fields. The syntax is explained in the section Fields Support.

Lastly, you might want to configure the position of preview window with --preview-window:

• --preview-window up:30% to put the window in the up position with height 30% of the total height of skim.
• --preview-window left:10:wrap to specify the wrap allows the preview window to wrap the output of the preview command.
• --preview-window wrap:hidden to hide the preview window at startup, later it can be shown by the action toggle-preview.

Fields support

Normally only plugin users need to understand this.

For example, you have the data source with the format:

<filename>:<line number>:<column number>

However, you want to search <filename> only when typing in queries. That means when you type 21, you want to find a <filename> that contains 21, but not matching line number or column number.

You can use sk --delimiter ':' --nth 1 to achieve this.

You can also use --with-nth to re-arrange the order of fields.

Range Syntax

• <num> -- to specify the num-th fields, starting with 1.
• start.. -- starting from the start-th fields and the rest.
• ..end -- starting from the 0-th field, all the way to end-th field, including end.
• start..end -- starting from start-th field, all the way to end-th field, including end.

Use as a library

Skim can be used as a library in your Rust crates.

First, add skim into your Cargo.toml:

[dependencies]
skim = { version = "<version>", default-features = false, features = [..] }

Note on features: - the cli feature is required to use skim as a cli, it should not be needed when using it as a library.

Basic usage

Then try to run this simple example:

extern crate skim;
use skim::prelude::*;
use std::io::Cursor;

pub fn main() {
    let options = SkimOptionsBuilder::default()
        .height("50%")
        .multi(true)
        .build()
        .unwrap();

    let input = "aaaaa\nbbbb\nccc".to_string();

    // `SkimItemReader` is a helper to turn any `BufRead` into a stream of `SkimItem`
    // `SkimItem` was implemented for `AsRef<str>` by default
    let item_reader = SkimItemReader::default();
    let items = item_reader.of_bufread(Cursor::new(input));

    // `run_with` would read and show items from the stream
    let selected_items = Skim::run_with(&options, Some(items))
        .map(|out| out.selected_items)
        .unwrap_or_else(|| Vec::new());

    for item in selected_items.iter() {
        println!("{}", item.output());
    }
}

Fine-grained usage

You can also gain fine-grained usage of skim as a library using tokio and async code, allowing you to dynamically interact with

Internal workings

Given an Option<SkimItemReceiver>, skim will read items accordingly, do its job and bring us back the user selection including the selected items, the query, etc. Note that:

• SkimItemReceiver is crossbeam::channel::Receiver<Arc<dyn SkimItem>>
• If it is none, it will invoke the given command and read items from command output
• Otherwise, it will read the items from the (crossbeam) channel.

Trait SkimItem is provided to customize how a line could be displayed, compared and previewed. It is implemented by default for AsRef<str>

Plus, SkimItemReader is a helper to convert a BufRead into SkimItemReceiver (we can easily turn a File or String into BufRead), so that you could deal with strings or files easily.

Check out more examples under the examples/ directory.

FAQ

How to ignore files?

Skim invokes find . to fetch a list of files for filtering. You can override this by setting the environment variable SKIM_DEFAULT_COMMAND. For example:

$ SKIM_DEFAULT_COMMAND="fd --type f || git ls-tree -r --name-only HEAD || rg --files || find ."
$ sk

You could put it in your .bashrc or .zshrc if you like it to be default.

Some files are not shown in Vim plugin

If you use the Vim plugin and execute the :SK command, you may find some of your files not shown.

As described in #3, in the Vim plugin, SKIM_DEFAULT_COMMAND is set to the command by default:

let $SKIM_DEFAULT_COMMAND = "git ls-tree -r --name-only HEAD || rg --files || ag -l -g \"\" || find ."

This means files not recognized by git won't be shown. You can either override the default with let $SKIM_DEFAULT_COMMAND = '' or locate the missing files by yourself.

Differences from fzf

fzf is a command-line fuzzy finder written in Go and skim tries to implement a new one in Rust!

This project is written from scratch. Some decisions of implementation are different from fzf. For example:

1. skim has an interactive mode.
2. skim supports pre-selection.
3. The fuzzy search algorithm is different.

More generally, skim's maintainers allow themselves some freedom of implementation. The goal is to keep skim as feature-full as fzf is, but the command flags might differ.

How to contribute

Create new issues if you encounter any bugs or have any ideas. Pull requests are warmly welcomed.

Troubleshooting

To troubleshoot what's happening, you can set the environment variable RUST_LOG to either debug or even trace, and set --log-file to a path. You can then read those logs during or after the execution to better understand what's happening. Don't hesitate to add those logs to an issue if you need help.

No line feed issues with nix, FreeBSD, termux

If you encounter display issues like:

$ for n in {1..10}; do echo "$n"; done | sk
  0/10 0/0.> 10/10  10  9  8  7  6  5  4  3  2> 1

For example

• https://github.com/skim-rs/skim/issues/412
• https://github.com/skim-rs/skim/issues/455

You need to set TERMINFO or TERMINFO_DIRS to the path of a correct terminfo database path

For example, with termux, you can add this in your bashrc:

export TERMINFO=/data/data/com.termux/files/usr/share/terminfo

Benchmarks

Shell script

The bench.sh script is available to benchmark the code against other versions or fzf using tmux and querying the output. This is by no means a precise or foolproof way of running benchmarks, but it has the added benefit of allowing us to benchmark against fzf and of giving us resource metrics.

You can use it directly using ./bench.sh <binary> -n <number of items> -r <number of runs>, or generate the data using ./bench.sh -g <output file> -n <number of items>, then ./bench.sh <binary> -f <file> -r <number of runs>

Criterion benchmarks

Criterion benchmarks are available to measure skim's performance more precisely. To run them, you need to generate input data using ./bench.sh -g benches/fixtures/10M.txt -n 10000000 && ./bench.sh -g benches/fixtures/1M.txt -n 1000000, then run cargo bench -j 1.

These will run for several minutes.