Overview
Teaching: 10 min
Exercises: 10 minQuestions
How can I tell Git to ignore files I don’t want to track?
Objectives
Configure Git to ignore specific files.
Explain why ignoring files can be useful.
What if we have files that we do not want Git to track for us? These could be backup files created by our editor, or intermediate files created during data analysis.
Our guac recipe has a “secret ingredient” that we don’t want anyone to know about. Our first thought is to hide it among lots of similar files, so we do this:
$ cd guac
$ touch secret_sauce_1.txt secret_sauce_2.txt secret_sauce_3.txt secret_sauce_4.txt
and see what Git says:
$ git status
On branch master
Untracked files:
(use "git add <file>..." to include in what will be committed)
secret_sauce_1.txt
secret_sauce_2.txt
secret_sauce_3.txt
secret_sauce_4.txt
nothing added to commit but untracked files present (use "git add" to track)
Putting these files under version control would be a waste of disk space. What’s worse, having them all listed could distract us from changes that actually matter. And, in fact, we don’t want to call attention to these files at all. So let’s tell Git to ignore them.
We do this by creating a file in the root directory of our project called .gitignore
:
$ nano .gitignore
$ cat .gitignore
secret_sauce*
These patterns tell Git to ignore any file whose name begins with
secret_sauce
.
(If any of these files were already being tracked,
Git would continue to track them.)
Once we have created this file,
the output of git status
is much cleaner:
$ git status
On branch master
Untracked files:
(use "git add <file>..." to include in what will be committed)
.gitignore
nothing added to commit but untracked files present (use "git add" to track)
The only thing Git notices now is the newly-created .gitignore
file.
You might think we wouldn’t want to track it,
but everyone we’re sharing our repository with will probably want to ignore
the same things that we’re ignoring.
Let’s add and commit .gitignore
:
$ git add .gitignore
$ git commit -m "Add the ignore file"
$ git status
# On branch master
nothing to commit, working directory clean
As a bonus, using .gitignore
helps us avoid accidentally adding to the repository files that we don’t want to track:
$ git add secret_sauce_4.txt
The following paths are ignored by one of your .gitignore files:
secret_sauce_4.txt
Use -f if you really want to add them.
If we really want to override our ignore settings,
we can use git add -f
to force Git to add something. For example,
git add -f secret_sauce_4.txt
.
We can also always see the status of ignored files if we want:
$ git status --ignored
On branch master
Ignored files:
(use "git add -f <file>..." to include in what will be committed)
secret_sauce_1.txt
secret_sauce_2.txt
secret_sauce_3.txt
secret_sauce_4.txt
nothing to commit, working directory clean
Ignoring Nested Files
Given a directory structure that looks like:
results/data results/plots
How would you ignore only
results/plots
and notresults/data
?Solution
As with most programming issues, there are a few ways that you could solve this. If you only want to ignore the contents of
results/plots
, you can change your.gitignore
to ignore only the/plots/
subfolder by adding the following line to your .gitignore:
results/plots/
If, instead, you want to ignore everything in
/results/
, but wanted to trackresults/data
, then you can addresults/
to your .gitignore and create an exception for theresults/data/
folder. The next challenge will cover this type of solution.Sometimes the
**
pattern comes in handy, too, which matches multiple directory levels. E.g.**/results/plots/*
would make git ignore theresults/plots
directory in any root directory.
Including Specific Files
How would you ignore all
.data
files in your root directory except forfinal.data
? Hint: Find out what!
(the exclamation point operator) doesSolution
You would add the following two lines to your .gitignore:
*.data # ignore all data files !final.data # except final.data
The exclamation point operator will include a previously excluded entry.
Ignoring all data Files in a Directory
Given a directory structure that looks like:
results/data/position/gps/a.data results/data/position/gps/b.data results/data/position/gps/c.data results/data/position/gps/info.txt results/plots
What’s the shortest
.gitignore
rule you could write to ignore all.data
files inresult/data/position/gps
? Do not ignore theinfo.txt
.Solution
Appending
results/data/position/gps/*.data
will match every file inresults/data/position/gps
that ends with.data
. The fileresults/data/position/gps/info.txt
will not be ignored.
The Order of Rules
Given a
.gitignore
file with the following contents:*.data !*.data
What will be the result?
Solution
The
!
modifier will negate an entry from a previously defined ignore pattern. Because the!*.data
entry negates all of the previous.data
files in the.gitignore
, none of them will be ignored, and all.data
files will be tracked.
Log Files
You wrote a script that creates many intermediate log-files of the form
log_01
,log_02
,log_03
, etc. You want to keep them but you do not want to track them throughgit
.
Write one
.gitignore
entry that excludes files of the formlog_01
,log_02
, etc.Test your “ignore pattern” by creating some dummy files of the form
log_01
, etc.You find that the file
log_01
is very important after all, add it to the tracked files without changing the.gitignore
again.Discuss with your neighbor what other types of files could reside in your directory that you do not want to track and thus would exclude via
.gitignore
.Solution
- append either
log_*
orlog*
as a new entry in your .gitignore- track
log_01
usinggit add -f log_01
Key Points
The
.gitignore
file tells Git what files to ignore.