Aaron Kelly's Blog

FZF

I discovered this program recently, and it’s so good I had to write a post about it

keybinds

The install script adds:

CTRL+R
CTRL+T
ALT-C

In my zsh shell these weren’t enabled by default, maybe one day I’ll figure out how to enable them.

Killer features

These options are what make fzf great for me

--preview
Opens a preview pane to view the output of the command. The preview pane also supports ANSI colours, so you can use any program that takes full advantage of this (syntax highlighting...)

--multi (-m)
Allows you to select multiple results with `TAB`. Pressing `ENTER` will echo the results back you to your terminal, or optionally, can be passed to a program.

Useful fzf queries

NOTE: more programming-specific queries are in A REPL for shell commands

Note: most of the below queries will by default have the --multi (-m) option enabled.

find and run program (e.g. midi player)

Here you go, a midi player which can easily search through 1000’s of files

fzf --multi --preview 'timidity {}'

find in file (put this in API if it looks useful):

#!/bin/bash

grep --line-buffered --color=never -r "" * | fzf

# with ag - respects .agignore and .gitignore
ag --nobreak --nonumbers --noheading . | fzf

# using ripgrep combined with preview
# find-in-file - usage: fif <searchTerm>
fif() {
  if [ ! "$#" -gt 0 ]; then echo "Need a string to search for!"; return 1; fi
  rg --files-with-matches --no-messages "$1" | fzf --preview "highlight -O ansi -l {} 2> /dev/null | rg --colors 'match:bg:yellow' --ignore-case --pretty --context 10 '$1' || rg --ignore-case --pretty --context 10 '$1' {}"
}

Find file by name and display contents

Find a file by name and display its contents in the preview pane:

fzf --preview 'find . -type f -name {q} | head -100 {}'

Search for file contents (using grep/ripgrep)

The contents of the file will be dispalyed in the search results:

grep --line-buffered --color=never --ignore-case --recursive "" | fzf

Generate a list, mark rows, perform action

This is useful for tasks such as:

searching bash history, marking command(s) you want to rerun, and running them as soon as fzf exits
searching currently installed programs, marking them, and upgrading only the marked ones

Searching bash history, execute command

A good replacement for bash’s history search CTRL+R is the built-in history search that comes with fzf:

You can also create your own!:

history | fzf -m | cut -c 8- | bash

Searching for installed applications and upgrading them

In this example, the results are processed using cut and then saved to a variable:

~ RST=$(apt list --installed | eval "fzf ${FZF_DEFAULT_OPTS} -m --header='search'" | cut -d '/' -f 1)
~ echo $RST
asciinema
baobab

Instead of saving to a variable, you could immediately pass those results to a program:

~ sudo apt install --only-upgrade $(apt list --installed | eval "fzf ${FZF_DEFAULT_OPTS} -m --header='search'" | cut -d '/' -f 1)

WARNING: apt does not have a stable CLI interface. Use with caution in scripts.

Reading package lists... Done
Building dependency tree       
Reading state information... Done
asciinema is already the newest version (2.0.2-1).
baobab is already the newest version (3.30.0-2).
0 upgraded, 0 newly installed, 0 to remove and 7 not upgraded

Instant search (WIKIs, search engines..)

Very handy when you want to get instant results! This uses w3m --dump to format the html page into plain text.

DuckDuckGo:

 : | fzf --multi --preview 'w3m -dump https://duckduckgo.com/\?q\={q}' --preview-window=up:70

Wikipedia - the exact title must match for the article to be found:

: | fzf --multi --preview 'w3m -dump https://en.wikipedia.org/wiki/{q}' --preview-window=up:70

Dark Souls 3 wiki - I remove the first n lines because it’s all boilerplate HTML:

: | fzf --multi --preview 'w3m -dump https://darksouls3.wiki.fextralife.com/{q} | tail -n +344' --preview-window=up:70

Resources

https://github.com/junegunn/fzf#preview-window

Or even better:

man fzf