Advanced fzf examples ====================== *(Last update: 2021/04/09)* * [Introduction](#introduction) * [Screen Layout](#screen-layout) * [`--height`](#--height) * [`fzf-tmux`](#fzf-tmux) * [Popup window support](#popup-window-support) * [Dynamic reloading of the list](#dynamic-reloading-of-the-list) * [Updating the list of processes by pressing CTRL-R](#updating-the-list-of-processes-by-pressing-ctrl-r) * [Toggling between data sources](#toggling-between-data-sources) * [Ripgrep integration](#ripgrep-integration) * [Using fzf as the secondary filter](#using-fzf-as-the-secondary-filter) * [Using fzf as interative Ripgrep launcher](#using-fzf-as-interative-ripgrep-launcher) * [Log tailing](#log-tailing) * [Key bindings for git objects](#key-bindings-for-git-objects) * [Files listed in `git status`](#files-listed-in-git-status) * [Branches](#branches) * [Commit hashes](#commit-hashes) * [Color themes](#color-themes) * [Generating fzf color theme from Vim color schemes](#generating-fzf-color-theme-from-vim-color-schemes) Introduction ------------ fzf is an interactive [Unix filter][filter] program that is designed to be used with other Unix tools. It reads a list of items from the standard input, allows you to select a subset of the items, and prints the selected ones to the standard output. You can think of it as an interactive version of *grep*, and it's already useful even if you don't know any of its options. ```sh # 1. ps: Feed the list of processes to fzf # 2. fzf: Interactively select a process using fuzzy matching algorithm # 3. awk: Take the PID from the selected line # 3. kill: Kill the process with the PID ps -ef | fzf | awk '{print $2}' | xargs kill -9 ``` [filter]: https://en.wikipedia.org/wiki/Filter_(software) While the above example succinctly summarizes the fundamental concept of fzf, you can build much more sophisticated interactive workflows using fzf once you learn its wide variety of features. - To see the full list of options and features, see `man fzf` - To see the latest additions, see [CHANGELOG.md](CHANGELOG.md) This document will guide you through some examples that will familiarize you with the advanced features of fzf. Screen Layout ------------- ### `--height` fzf by default opens in fullscreen mode, but it's not always desirable. Oftentimes, you want to see the current context of the terminal while using fzf. `--height` is an option for opening fzf below the cursor in non-fullscreen mode so you can still see the previous commands and their results above it. ```sh fzf --height=40% ``` ![image](https://user-images.githubusercontent.com/700826/113379893-c184c680-93b5-11eb-9676-c7c0a2f01748.png) You might also want to experiment with other layout options such as `--layout=reverse`, `--info=inline`, `--border`, `--margin`, etc. ```sh fzf --height=40% --layout=reverse fzf --height=40% --layout=reverse --info=inline fzf --height=40% --layout=reverse --info=inline --border fzf --height=40% --layout=reverse --info=inline --border --margin=1 fzf --height=40% --layout=reverse --info=inline --border --margin=1 --padding=1 ``` ![image](https://user-images.githubusercontent.com/700826/113379932-dfeac200-93b5-11eb-9e28-df1a2ee71f90.png) *(See `Layout` section of the man page to see the full list of options)* But you definitely don't want to repeat `--height=40% --layout=reverse --info=inline --border --margin=1 --padding=1` every time you use fzf. You could write a wrapper script or shell alias, but there is an easier option. Define `$FZF_DEFAULT_OPTS` like so: ```sh export FZF_DEFAULT_OPTS="--height=40% --layout=reverse --info=inline --border --margin=1 --padding=1" ``` ### `fzf-tmux` Before fzf had `--height` option, we would open fzf in a tmux split pane not to take up the whole screen. This is done using `fzf-tmux` script. ```sh # Open fzf on a tmux split pane below the current pane. # Takes the same set of options. fzf-tmux --layout=reverse ``` ![image](https://user-images.githubusercontent.com/700826/113379973-f1cc6500-93b5-11eb-8860-c9bc4498aadf.png) The limitation of `fzf-tmux` is that it only works when you're on tmux unlike `--height` option. But the advantage of it is that it's more flexible. (See `man fzf-tmux` for available options.) ```sh # On the right (50%) fzf-tmux -r # On the left (30%) fzf-tmux -l30% # Above the cursor fzf-tmux -u30% ``` ![image](https://user-images.githubusercontent.com/700826/113379983-fa24a000-93b5-11eb-93eb-8a3d39b2f163.png) ![image](https://user-images.githubusercontent.com/700826/113380001-0577cb80-93b6-11eb-95d0-2ba453866882.png) ![image](https://user-images.githubusercontent.com/700826/113380040-1d4f4f80-93b6-11eb-9bef-737fb120aafe.png) #### Popup window support But here's the really cool part; tmux 3.2 (stable version is not yet released as of now) supports popup windows. So if you have tmux built from the latest source, you can open fzf in a popup window, which is quite useful if you frequently use split panes. ```sh # Open tmux in a tmux popup window (default size: 50% of the screen) fzf-tmux -p # 80% width, 60% height fzf-tmux -p 80%,60% ``` ![image](https://user-images.githubusercontent.com/700826/113380106-4a9bfd80-93b6-11eb-8cee-aeb1c4ce1a1f.png) > You might also want to check out my tmux plugins which support this popup > window layout. > > - https://github.com/junegunn/tmux-fzf-url > - https://github.com/junegunn/tmux-fzf-maccy Dynamic reloading of the list ----------------------------- fzf can dynamically update the candidate list using an arbitrary program with `reload` bindings (The design document for `reload` can be found [here][reload]). [reload]: https://github.com/junegunn/fzf/issues/1750 ### Updating the list of processes by pressing CTRL-R This example shows how you can set up a binding for dynamically updating the list without restarting fzf. ```sh (date; ps -ef) | fzf --bind='ctrl-r:reload(date; ps -ef)' \ --header=$'Press CTRL-R to reload\n\n' --header-lines=2 \ --preview='echo {}' --preview-window=down,3,wrap \ --layout=reverse --height=80% | awk '{print $2}' | xargs kill -9 ``` ![image](https://user-images.githubusercontent.com/700826/113465047-200c7c00-946c-11eb-918c-268f37a900c8.png) - The initial command is `(date; ps -ef)`. It prints the current date and time, and the list of the processes. - With `--header` option, you can show any message as the fixed header. - To disallow selecting the first two lines (`date` and `ps` header), we use `--header-lines=2` option. - `--bind='ctrl-r:reload(date; ps -ef)'` binds CTRL-R to `reload` action that runs `date; ps -ef`, so we can update the list of the processes by pressing CTRL-R. - We use simple `echo {}` preview option, so we can see the entire line on the preview window below even if it's too long ### Toggling between data sources You're not limiited to just one reload binding. Set up multiple bindings so you can switch between data sources. ```sh find * | fzf --prompt 'All> ' \ --header 'CTRL-D: Directories / CTRL-F: Files' \ --bind 'ctrl-d:change-prompt(Directories> )+reload(find * -type d)' \ --bind 'ctrl-f:change-prompt(Files> )+reload(find * -type f)' ``` ![image](https://user-images.githubusercontent.com/700826/113465073-4af6d000-946c-11eb-858f-2372c0955f67.png) ![image](https://user-images.githubusercontent.com/700826/113465072-46321c00-946c-11eb-9b6f-cda3951df579.png) Ripgrep integration ------------------- ### Using fzf as the secondary filter * Requires [bat][bat] * Requires [Ripgrep][rg] [bat]: https://github.com/sharkdp/bat [rg]: https://github.com/BurntSushi/ripgrep fzf is pretty fast for filtering a list that you will rarely have to think about its performance. But it is not the right tool for searching for text inside many large files, and in that case you should definitely use something like [Ripgrep][rg]. In the next example, Ripgrep is the primary filter that searches for the given text in files, and fzf is used as the secondary fuzzy filter that adds interactivity to the workflow. And we use [bat][bat] to show the matching line in the preview window. This is a bash script and it will not run as expected on other non-compliant shells. To avoid the compatibility issue, let's save this snippet as a script file called `rfv`. ```bash #!/usr/bin/env bash # 1. Search for text in files using Ripgrep # 2. Interactively narrow down the list using fzf # 3. Open the file in Vim IFS=: read -ra selected < <( rg --color=always --line-number --no-heading --smart-case "${*:-}" | fzf --ansi \ --color "hl:-1:underline,hl+:-1:underline:reverse" \ --delimiter : \ --preview 'bat --color=always {1} --highlight-line {2}' \ --preview-window 'up,60%,border-bottom,+{2}+3/3,~3' ) [ -n "${selected[0]}" ] && vim "${selected[0]}" "+${selected[1]}" ``` And run it with an initial query string. ```sh # Make the script executable chmod +x rfv # Run it with the initial query "algo" ./rfv algo ``` > Ripgrep will perform the initial search and list all the lines that contain `algo`. Then we further narrow down the list on fzf. ![image](https://user-images.githubusercontent.com/700826/113683873-a42a6200-96ff-11eb-9666-26ce4091b0e4.png) I know it's a lot to digest, let's try to break down the code. - Ripgrep prints the matching lines in the following format ``` man/man1/fzf.1:54:.BI "--algo=" TYPE man/man1/fzf.1:55:Fuzzy matching algorithm (default: v2) man/man1/fzf.1:58:.BR v2 " Optimal scoring algorithm (quality)" src/pattern_test.go:7: "github.com/junegunn/fzf/src/algo" ``` The first token delimited by `:` is the file path, and the second token is the line number of the matching line. They respectively correspond to `{1}` and `{2}` in the preview command. - `--preview 'bat --color=always {1} --highlight-line {2}'` - As we run `rg` with `--color=always` option, we should tell fzf to parse ANSI color codes in the input by setting `--ansi`. - We customize how fzf colors various text elements using `--color` option. `-1` tells fzf to keep the original color from the input. See `man fzf` for available color options. - The value of `--preview-window` option consists of 5 components delimited by `,` 1. `up` — Position of the preview window 1. `60%` — Size of the preview window 1. `border-bottom` — Preview window border only on the bottom side 1. `+{2}+3/3` — Scroll offset of the preview contents 1. `~3` — Fixed header - Let's break down the latter two. We want to display the bat output in the preview window with a certain scroll offset so that the matching line is positioned near the center of the preview window. - `+{2}` — The base offset is extracted from the second token - `+3` — We add 3 lines to the base offset to compensate for the header part of `bat` output - ``` ───────┬────────────────────────────────────────────────────────── │ File: CHANGELOG.md ───────┼────────────────────────────────────────────────────────── 1 │ CHANGELOG 2 │ ========= 3 │ 4 │ 0.26.0 5 │ ------ ``` - `/3` adjusts the offset so that the matching line is shown at a third position in the window - `~3` makes the top three lines fixed header so that they are always visible regardless of the scroll offset - Once we selected a line, we open the file with `vim` (`vim "${selected[0]}"`) and move the cursor to the line (`+${selected[1]}`). ### Using fzf as interative Ripgrep launcher We have learned that we can bind `reload` action to a key (e.g. `--bind=ctrl-r:execute(ps -ef)`). In the next example, we are going to **bind `reload` action to `change` event** so that whenever the user *changes* the query string on fzf, `reload` action is triggered. Here is a variation of the above `rfv` script. fzf will restart Ripgrep every time the user updates the query string on fzf. Searching and filtering is completely done by Ripgrep, and fzf merely provides the interactive interface. So we lose the "fuzziness", but the performance will be better on larger projects, and it will free up memory as you narrow down the results. ```bash #!/usr/bin/env bash # 1. Search for text in files using Ripgrep # 2. Interactively restart Ripgrep with reload action # 3. Open the file in Vim RG_PREFIX="rg --column --line-number --no-heading --color=always --smart-case " INITIAL_QUERY="${*:-}" IFS=: read -ra selected < <( FZF_DEFAULT_COMMAND="$RG_PREFIX $(printf %q "$INITIAL_QUERY")" \ fzf --ansi \ --disabled --query "$INITIAL_QUERY" \ --bind "change:reload:sleep 0.1; $RG_PREFIX {q} || true" \ --delimiter : \ --preview 'bat --color=always {1} --highlight-line {2}' \ --preview-window 'up,60%,border-bottom,+{2}+3/3,~3' ) [ -n "${selected[0]}" ] && vim "${selected[0]}" "+${selected[1]}" ``` ![image](https://user-images.githubusercontent.com/700826/113684212-f9ff0a00-96ff-11eb-8737-7bb571d320cc.png) - Instead of starting fzf in `rg ... | fzf` form, we start fzf without an explicit input, but with a custom `FZF_DEFAULT_COMMAND` variable. This way fzf can kill the initial Ripgrep process it starts with the initial query. Otherwise, the initial Ripgrep process will keep consuming system resources even after `reload` is triggered. - Filtering is no longer a responsibitiliy of fzf; hence `--disabled` - `{q}` in the reload command evaluates to the query string on fzf prompt. - `sleep 0.1` in the reload command is for "debouncing". This small delay will reduce the number of intermediate Ripgrep processes while we're typing in a query. Log tailing ----------- fzf can run long-running preview commands and render partial results before completion. And when you specify `follow` flag in `--preview-window` option, fzf will "`tail -f`" the result, automatically scrolling to the bottom. ```bash # With "follow", preview window will automatically scroll to the bottom. # "\033[2J" is an ANSI escape sequence for clearing the screen. # When fzf reads this code it clears the previous preview contents. fzf --preview-window follow --preview 'for i in $(seq 100000); do echo "$i" sleep 0.01 (( i % 300 == 0 )) && printf "\033[2J" done' ``` ![image](https://user-images.githubusercontent.com/700826/113473303-dd669600-94a3-11eb-88a9-1f61b996bb0e.png) Admittedly, that was a silly example. Here's a practical one for browsing Kubernetes pods. ```bash #!/usr/bin/env bash read -ra tokens < <( kubectl get pods --all-namespaces | fzf --info=inline --layout=reverse --header-lines=1 --border \ --prompt "$(kubectl config current-context | sed 's/-context$//')> " \ --header $'Press CTRL-O to open log in editor\n\n' \ --bind ctrl-/:toggle-preview \ --bind 'ctrl-o:execute:${EDITOR:-vim} <(kubectl logs --namespace {1} {2}) > /dev/tty' \ --preview-window up,follow \ --preview 'kubectl logs --follow --tail=100000 --namespace {1} {2}' "$@" ) [ ${#tokens} -gt 1 ] && kubectl exec -it --namespace "${tokens[0]}" "${tokens[1]}" -- bash ``` ![image](https://user-images.githubusercontent.com/700826/113473547-1d7a4880-94a5-11eb-98ef-9aa6f0ed215a.png) - The preview window will *"log tail"* the pod - Holding on to a large amount of log will consume a lot of memory. So we limited the initial log amount with `--tail=100000`. - With `execute` binding, you can press CTRL-O to open the log in your editor without leaving fzf - Select a pod (with an enter key) to `kubectl exec` into it Key bindings for git objects ---------------------------- I have [blogged](https://junegunn.kr/2016/07/fzf-git) about my fzf+git key bindings a few years ago. I'm going to show them here again, because they are seriously useful. ### Files listed in `git status` CTRL-GCTRL-F ![image](https://user-images.githubusercontent.com/700826/113473779-a9d93b00-94a6-11eb-87b5-f62a8d0a0efc.png) ### Branches CTRL-GCTRL-B ![image](https://user-images.githubusercontent.com/700826/113473758-87dfb880-94a6-11eb-82f4-9218103f10bd.png) ### Commit hashes CTRL-GCTRL-H ![image](https://user-images.githubusercontent.com/700826/113473765-91692080-94a6-11eb-8d38-ed4d41f27ac1.png) The full source code can be found [here](https://gist.github.com/junegunn/8b572b8d4b5eddd8b85e5f4d40f17236). Color themes ------------ You can customize how fzf colors the text elements with `--color` option. Here are a few color themes. Note that you need a terminal emulator that can display 24-bit colors. ```sh # junegunn/seoul256.vim (dark) export FZF_DEFAULT_OPTS='--color=bg+:#3F3F3F,bg:#4B4B4B,border:#6B6B6B,spinner:#98BC99,hl:#719872,fg:#D9D9D9,header:#719872,info:#BDBB72,pointer:#E12672,marker:#E17899,fg+:#D9D9D9,preview-bg:#3F3F3F,prompt:#98BEDE,hl+:#98BC99' ``` ![seoul256](https://user-images.githubusercontent.com/700826/113475011-2c192d80-94ae-11eb-9d17-1e5867bae01f.png) ```sh # junegunn/seoul256.vim (light) export FZF_DEFAULT_OPTS='--color=bg+:#D9D9D9,bg:#E1E1E1,border:#C8C8C8,spinner:#719899,hl:#719872,fg:#616161,header:#719872,info:#727100,pointer:#E12672,marker:#E17899,fg+:#616161,preview-bg:#D9D9D9,prompt:#0099BD,hl+:#719899' ``` ![seoul256-light](https://user-images.githubusercontent.com/700826/113475022-389d8600-94ae-11eb-905f-0939dd535837.png) ```sh # morhetz/gruvbox export FZF_DEFAULT_OPTS='--color=bg+:#3c3836,bg:#32302f,spinner:#fb4934,hl:#928374,fg:#ebdbb2,header:#928374,info:#8ec07c,pointer:#fb4934,marker:#fb4934,fg+:#ebdbb2,prompt:#fb4934,hl+:#fb4934' ``` ![gruvbox](https://user-images.githubusercontent.com/700826/113475042-494dfc00-94ae-11eb-9322-cd03a027305a.png) ```sh # arcticicestudio/nord-vim export FZF_DEFAULT_OPTS='--color=bg+:#3B4252,bg:#2E3440,spinner:#81A1C1,hl:#616E88,fg:#D8DEE9,header:#616E88,info:#81A1C1,pointer:#81A1C1,marker:#81A1C1,fg+:#D8DEE9,prompt:#81A1C1,hl+:#81A1C1' ``` ![nord](https://user-images.githubusercontent.com/700826/113475063-67b3f780-94ae-11eb-9b24-5f0d22b63399.png) ```sh # tomasr/molokai export FZF_DEFAULT_OPTS='--color=bg+:#293739,bg:#1B1D1E,border:#808080,spinner:#E6DB74,hl:#7E8E91,fg:#F8F8F2,header:#7E8E91,info:#A6E22E,pointer:#A6E22E,marker:#F92672,fg+:#F8F8F2,prompt:#F92672,hl+:#F92672' ``` ![molokai](https://user-images.githubusercontent.com/700826/113475085-8619f300-94ae-11eb-85e4-2766fc3246bf.png) ### Generating fzf color theme from Vim color schemes The Vim plugin of fzf can generate `--color` option from the current color scheme according to `g:fzf_colors` variable. You can find the detailed explanation [here](https://github.com/junegunn/fzf/blob/master/README-VIM.md#explanation-of-gfzf_colors). Here is an example. Add this to your Vim configuration file. ```vim let g:fzf_colors = \ { 'fg': ['fg', 'Normal'], \ 'bg': ['bg', 'Normal'], \ 'preview-bg': ['bg', 'NormalFloat'], \ 'hl': ['fg', 'Comment'], \ 'fg+': ['fg', 'CursorLine', 'CursorColumn', 'Normal'], \ 'bg+': ['bg', 'CursorLine', 'CursorColumn'], \ 'hl+': ['fg', 'Statement'], \ 'info': ['fg', 'PreProc'], \ 'border': ['fg', 'Ignore'], \ 'prompt': ['fg', 'Conditional'], \ 'pointer': ['fg', 'Exception'], \ 'marker': ['fg', 'Keyword'], \ 'spinner': ['fg', 'Label'], \ 'header': ['fg', 'Comment'] } ``` Then you can see how the `--color` option is generated by printing the result of `fzf#wrap()`. ```vim :echo fzf#wrap() ``` Use this command to append `export FZF_DEFAULT_OPTS="..."` line to the end of the current file. ```vim :call append('$', printf('export FZF_DEFAULT_OPTS="%s"', matchstr(fzf#wrap().options, "--color[^']*"))) ```