How to diff one file to an arbitrary version in Git?

Question

How can I diff a file, say pom.xml, from the master branch to an arbitrary older version in Git?

Casilde

Answer 1

You can do:

git diff master~20:pom.xml pom.xml

... to compare your current pom.xml to the one from master 20 revisions ago through the first parent. You can replace master~20, of course, with the object name (SHA1sum) of a commit or any of the many other ways of specifying a revision.

Note that this is actually comparing the old pom.xml to the version in your working tree, not the version committed in master. If you want that, then you can do the following instead:

git diff master~20:pom.xml master:pom.xml

Serviceberry

Note that this doesn't just work for files, it also works for (sub)directories as well, for example git diff <revision>:foo/ HEAD:foo/. – Vaudevillian

Also note that on windows you need to use forward slashes for directories if you are using a revision specifier or git will give you an error about the file/directory not existing in that revision. – Tedda

@DylanNissley or it will give you no error and no diff. That's what I see. In any case, thank you for the hint about using forward slashes instead of backslashes. – Jim

With windows files I've found it easier to change directory and then call git diff master~20:./pom.xml ./pom.xml – Wanderjahr

Some version of git require "--" between the <revision> & <path> – Hunley

Answer 2

git diff <revision> <path>

For example:

git diff b0d14a4 foobar.txt

Thromboplastic

does not work for version 1.7.11 if file is not in current directory. Example: 'git diff f76d078 test/Config' yields "error: Could not access 'test/f76d078'" – Sensual

@user1663987 just pass a full path relative to the project root: git diff <revision> root/path/file. – Vaudevillian

test/Config is relative to the root (as in test is a sub-directory of the root). but then your example root/path/file would seem to INCLUDE the root? – Sensual

Answer 3

If you want to see the difference between the last commit of a single file you can do:

git log -p -1 filename

This will give you the diff of the file in git, is not comparing your local file.

Tutor

this is not returning anything – Simian

@AndreiCristianProdan Then you have no changes there. You can increment the -1 step by step until you get the changes. – Circus

This is very nice. I created a bash function that might be useful: gitlog () { git log -${3:-p} -${2:-1} $1; } Used like: gitlog Rakefile or gitlog Rakefile 5 and gitlog Rakefile 10 s. The first shows one diff; the second shows five diffs; the third shows ten --no-patch. – Deviltry

works just fine with WSL Ubuntu 20.04 LTS running on Windows 11. – Firebreak

Answer 4

To see what was changed in a file in the last commit:

git diff HEAD~1 -- path/to/file

You can change the number (~1) to the n-th commit which you want to diff with.

Galluses

This answer is really just a specific case of this more general answer, where HEAD~1 is substituted for <revision>, which makes this answer a duplicate. – Vaudevillian

this isn't working! fatal: ambiguous argument 'HEAD~1': unknown revision or path not in the working tree. Use '--' to separate paths from revisions – Simian

This answer is simple and functional for me. – Semination

"--" separator is missing, I have just fixed – Tanner

This works better for me! using WSL Ubuntu 20.04 LTS running on Windows 11. – Firebreak

Answer 5

git diff -w HEAD origin/master path/to/file

-w ignores whitespaces

Workingwoman

You could at least give some explanation as to what the -w flag means. Writing a solution that works is great, but I personally wouldn't use some random command without knowing what each flag in it means. – Heliograph

@TalKohavy You are right, I wrote that in a hurry, I have updated the answer. – Workingwoman

Answer 6

Generic Syntax :

$git diff oldCommit..newCommit -- **FileName.xml > ~/diff.txt

for all files named "FileName.xml" anywhere in your repo.

Notice the space between "--" and "**"

Answer for your question:

$git checkout master
$git diff oldCommit..HEAD -- **pom.xml 
or
$git diff oldCommit..HEAD -- relative/path/to/pom.xml 

as always with git, you can use a tag/sha1/"HEAD^" to id a commit.

Tested with git 1.9.1 on Ubuntu.

Bataan

too verbose, almost useless. – Firebreak

Answer 7

If neither commit is your HEAD then bash's brace expansion proves really useful, especially if your filenames are long, the example above:

git diff master~20:pom.xml master:pom.xml

Would become

git diff {master~20,master}:pom.xml

More on Brace expansion with bash.

Nesto

Answer 8

For comparing to 5 commit to the current one, both on master, just simply do:

git diff master~5:pom.xml master:pom.xml

Also you can refer to commit hash number, for example if the hash number is x110bd64, you can do something like this to see the difference:

git diff x110bd64 pom.xml

Zebedee

Answer 9

git diff master~20 -- pom.xml

Works if you are not in master branch too.

Baro

Answer 10

If you are fine using a graphical tool (or even prefer it) you can:

gitk pom.xml

In gitk you can then click any commit (to "select" it) and right click any other commit to select "Diff this -> selected" or "Diff selected -> this" in the popup menu, depending on what order you prefer.

Autolycus

Answer 11

For people interested in doing the same from GitHub, see comparing commits across time.

Sparge

Answer 12

If you need to diff on a single file in a stash for example you can do

git diff stash@{0} -- path/to/file

Applegate

Answer 13

lets say you want to diff the file interrupt.c located in firmware/src/

---

difftool between working area (what yet to be committed or staged) and latest commit:

git difftool head firmware/src/interrupt.c

or

git difftool head *interrupt.c

Note: to diff x versions before the last committed version replace "head" with head~x. For example replace "head" with "head~2" to diff between working area and 2 versions prior to the latest commit

---

difftool between two specific committed versions:

first get the ids for the versions you want to compare by using next line

git log --oneline

you will get a list of all your committed version. choose two and copy their id's.

enter the ids inside {}:

git difftool {2fae9e6,a21dd00} firmware/src/interrupt.c

or

git difftool {2fae9e6,a21dd00} *interrupt.c

Note: if there is no difference between the files, nothing will open. You will just get an empty line in the git bash

Immemorial

Answer 14

If you are looking for the diff on a specific commit and you want to use the github UI instead of the command line (say you want to link it to other folks), you can do:

https://github.com/<org>/<repo>/commit/<commit-sha>/<path-to-file>

For example:

https://github.com/grails/grails-core/commit/02942c5b4d832b856fbc04c186f1d02416895a7e/grails-test-suite-uber/build.gradle

Note the Previous and Next links at the top right that allow you to navigate through all the files in the commit.

This only works for a specific commit though, not for comparing between any two arbitrary versions.

Anglophobe