Excellent Utilities: McFly – navigate through your shell history

Last Updated on May 22, 2022

This is a new series highlighting best-of-breed utilities. We’re covering a wide range of utilities including tools that boost your productivity, help you manage your workflow, and lots more besides.

I spend an inordinate amount of time tapping away at the command line. My default shell is bash. Like other shells, bash keeps a history of all the commands I’ve typed. For bash, this history is stored in the ~/.bash_history file. While the up arrow traverses through your history, it’s often not an efficient way of locating commands. Step forward ctrl-r. Anything that reduces the number of keystrokes improves my efficiency.

Press ctrl-r. The shell prompt changes to (reverse-i-search). Now start typing the command or a part of the command. In the example below, I’ve typed ss. There’s no need to remember long complicated commands.

Even though ctrl-r is a time-saver, you may not be aware of an improved method of navigating through your shell history. The tool is called McFly. No, not the English pop band. Instead, it’s a tiny utility that replaces the functionality offered by ctrl-r with an intelligent search engine. Unlike bash’s ctrl-r, it also takes into account your working directory and the context of recently executed commands. The tool’s suggestions are prioritized in real time with a small neural network instead of a simple linear function.

McFly is written in the Rust programming language. If you want to help the project, you might want to learn Rust. We’ve compiled an article recommending great free books to learn Rust.

Installation

I distro hop more often than the lifespan of the common fruit fly (~ 40-50 days). Currently my distro of the month is Arch Linux. There’s a package for McFly in the Arch User Repository. This packages installs mcfly.bash into /usr/share/doc/mcfly/

After installing the package, edit ~/.bashrc and add the following lines to the end of the file:

if [[ -r /usr/share/doc/mcfly/mcfly.bash ]]; then
source /usr/share/doc/mcfly/mcfly.bash
fi

The directory path to mcfly.bash depends on how the software is installed.

Run . ~/.bashrc or restart your terminal emulator. The first time this bash script is run you receive the following notification:

McFly: Importing Bash history for the first time. This may take a minute or two…done.

Now you’re ready to efficiently navigate your shell history.

Next page: Page 2 – In Operation

Pages in this article:
Page 1 – Introduction / Installation
Page 2 – In Operation
Page 3 – Other Features
Page 4 – Summary

Complete list of articles in this series: