As a programmer or someone who spends a lot of time in command line shells, it’s likely that you regularly move around directories in ways that might feel less than efficient. Especially if you often visit the same directories every day.
The routine probably goes a bit like this:
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cd ~/Development
ls # look around...
cd project
# whoops, never mind, let's go back...
cd ..
# time to start something new...
mkdir new_project
cd new_project
# need to check something in that other directory...
cd ../project
Maybe with a bit more experience, you have some tab-completion tricks up your sleeve to avoid typing these full directory names, so in reality it looks more like:
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cd ~/Dev<TAB>
ls # look around...
cd pro<TAB>
cd ..
mkdir new_project
cd new<TAB>
cd ../pro<TAB>
Great. You saved about 20 keystrokes. That’s commendable. Yes, you could
also use the return value from the mkdir command to immediately move
into the newly created directory (cd !$). And you could just remember
that project/ is nested inside Development/ so that you don’t need
to ls around to find your way. The reality is that people are not
computers and memorizing your entire directory’s tree structure is a
trick that only impresses people who far too much time on their hands.
But what about this?
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j d
j p
cd ..
mkdir new_project
cd new<TAB>
j p
The most obvious benefit is that this took 18 fewer keystrokes to
accomplish the same goals but what may not be so obvious is that the j
d (or j dev, j develop, etc.) command will now take you to
~/Development/ and j p to ~/Development/project from anywhere
inside your filesystem. So this relatively small gain in typing
efficiency will compound with time.
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cd /usr/local/lib/something/log/
j p
pwd
~/Development/project
How does it work? AutoJump
AutoJump is magic cape that lets you fly around directories in your command line. The official description of the tool is “a faster way to navigate your filesystem” — but that doesn’t quite do it justice. It a bit of an undersell. My completely made up estimate is that Autojump has saved me from at least a whole year of typing. At the very least that’s how it feels.
How Autojump works
This command:
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j project
/Users/olivierlacan/Development/project
Works just the same as this command:
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j p
/Users/olivierlacan/Development/project
Why? Because AutoJump remembers all of the directories you move
into with the cd command or with its own j command. And more
important, AutoJump does fuzzy matching. Meaning it will look
for a directory you’ve visited before that contains the same string of
letters you provide, even if you only provide one letter.
What if you have two directories that start with the letter p? That’s
where it gets interesting.
The first time you type cd directory_name, Autojump logs the absolute
path to that directory and assigns it as weight (or rating) of 10.0.
So if you do:
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cd /var
You will see the following in the j -s command (s stands for “stats”):
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10.0: /var
What if you visit /var again?
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14.1: /var
And so on. If you visit a directory often the rating for that directory will increase. In my case, you can easily guess what I spend most of my time doing by looking at my top 5:
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j -s
(...)
234.7: /Users/olivierlacan/Development/cs/campus
262.7: /Users/olivierlacan/Development/rubyheroes/rubyheroes.com
417.4: /Users/olivierlacan/Development/perso/orientation
874.1: /Users/olivierlacan/Development/cs/CodeSchool
________________________________________
10810: total weight
198: number of entries
0.00: current directory weight
data: /Users/olivierlacan/Library/autojump/autojump.txt
Since both my first (CodeSchool) and fourth (campus) directories
contain the letter c. How does AutoJump decide where to go? Once again,
the rating.
Since campus has a much lower rating, AutoJump will first take me to
CodeSchool. However, if I repeat the j c command, it will try the
next highest rated directory that matches the letter c.
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j c
/Users/olivierlacan/Development/cs/CodeSchool
j c
/Users/olivierlacan/Development/cs/campus
If you don’t like to fly blind and assume AutoJump will make the right choice for you, it’s also possible to see what directories match a specific string of letters you provide:
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j c<TAB><TAB><TAB>
$ j c__
c__1__/Users/olivierlacan/Development/cs/CodeSchool
c__2__/Users/olivierlacan/Development/cs/campus
c__3__/Users/olivierlacan/Development/perso/keep-a-changelog
c__4__/Users/olivierlacan/Development/perso/olivierlacan.com
$ j c__4
/Users/olivierlacan/Development/perso/olivierlacan.com
After display a numbered list of directories that match the supplied
argument, AutoJump will prefill the command j c__ and let you type
the number for whichever directory you which to jump to.
Advanced Features
- the
jc(child) command will scope the search to only subdirectories of the current directory, which is very useful to find nestedlogdirectories. - the
jo(open) command will open the matched directory in your operating system’s file manager. - the
j -icommand will increase the weight of the current directory. - the
j -dcommand will decrease the weight of the current directory. - the
j --purgecommand will wipe the weighted list of directories AutoJump relies on if you need to start from scratch.
Installing AutoJump
While AutoJump does require Python, it’s such a simple tool supported by
most shells (bash, zsh, fish) that you can install AutoJump via many
Linux package managers. For macOS I recommend Homebrew’s brew
install autojump which couldn’t be simplier although do remember that
you have to source AutoJump in your .bash_profile or .zshrc by
adding the following line:
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[ -f /usr/local/etc/profile.d/autojump.sh ] && . /usr/local/etc/profile.d/autojump.sh
It checks that the AutoJump script is available and simply loads it in your shell.
You can also clone the git repository and use the manual installation procedure if you want to stay on the bleeding edge but it’s an incredibly stable tool thanks to its simplicity. I don’t think I’ve encountered a single bug in years of usage.