alligator's blog

Making your own little world with fzf

Mar 22, 2023

In-between the interesting tasks like writing code or debugging, there's lots of little, routine things to do. This post is about how I do these quicker with fzf.


fzf is a general purpose tool for picking a thing from a list of things. It reads the list from stdin, and writes the selected item to stdout. What's in the list is up to you, as is what you do with it.

Here's some ways I use it, in increasing complexity.

Level 1 - .sln files

We have a monorepo containing lots of services, each of which has it's own .sln file. This tiny script has saved me many minutes clicking around Windows explorer to open the .sln for a service:

devenv $(fd -a .sln | fzf)

It uses fd to recursively find files ending in .sln, then fzf to pick one, then opens that file in devenv (Visual Studio).

Level 2 - Recent git branches

This shows me a list of git branches, sorted by how recently I switched to them:

current_branch=$(git branch --show-current)

ref=$(git reflog -1000 --format="%cs %gs" \
| rg -i "checkout: moving from" \
| awk '!dupes[$5]++ { print $1, $5 }' \
| fzf -n 2 --header="current branch: $current_branch" \
| awk '{ print $2 }')

git checkout "$ref"

This looks complicated, but most of it is plumbing to get the list of branches. It uses git reflog, ripgrep and awk to get a list of branches and the date they were last used, like this:

2023-03-21 latest-branch
2023-03-14 old-branch
2023-01-12 older-branch

Which fzf then sorts alphabetically and shows from the bottom up, so you see the most recent branch first. The -n 2 flag tells fzf to search in the second field, i.e. the branch name.

Usually I want to switch to the most recent branch, which will be the default item selected. With this script I can run it, quickly check if the branch is what I expected, and press enter to switch to it.

Level 3 - As a filter in a larger program

We have lots of services with HTTP APIs and Swagger pages letting you poke at those APIs. I often want to open a service's swagger page, but I don't know it's address.

I can get that information from an API, so I have python script like this:

# get the service names from an API
fzf_input = '\n'.join(service_names)

p ='fzf', input=fzf_input, capture_output=True, encoding='utf-8')
if p.returncode != 0:
selected_service_name = p.stdout.strip()

# look up the service address for the selected name
# and open it in a browser

Shelling out to fzf is easy, especially in python since blocks until the program exits. This script shows me a list of services, I pick one, and it's Swagger page opens in my browser.

These are just some of the ways I use fzf to create my own little world of terminal utilities.

Speeding up these routine tasks isn't really about saving time. It's about staying focused and avoiding distractions. Clicking around a slow UI or a file explorer is prime distraction time for me.

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