How do I diff the same file between two different commits on the same branch?

Question

In Git, how could I compare the same file between two different commits (not contiguous) on the same branch (master for example)?

I'm searching for a compare feature like the one in Visual SourceSafe (VSS) or Team Foundation Server (TFS).
Is it possible in Git?

Answer 1

From the git-diff manpage:

git diff [--options] <commit> <commit> [--] [<path>...]

For instance, to see the difference for a file "main.c" between now and two commits back, here are three equivalent commands:

$ git diff HEAD^^ HEAD main.c
$ git diff HEAD^^..HEAD -- main.c
$ git diff HEAD~2 HEAD -- main.c

Answer 2

You can also compare two different files in two different revisions, like this:

git diff <revision_1>:<file_1> <revision_2>:<file_2>

Answer 3

If you have configured the "difftool" you can use

git difftool revision_1:file_1 revision_2:file_2

Example: Comparing a file from its last commit to its previous commit on the same branch: Assuming that if you are in your project root folder

$git difftool HEAD:src/main/java/com.xyz.test/MyApp.java HEAD^:src/main/java/com.xyz.test/MyApp.java

You should have the following entries in your ~/.gitconfig or in project/.git/config file. Install the p4merge [This is my preferred diff and merge tool]

[merge]
    tool = p4merge
    keepBackup = false
[diff]
    tool = p4merge
    keepBackup = false
[difftool "p4merge"]
    path = C:/Program Files (x86)/Perforce/p4merge.exe
[mergetool]
    keepBackup = false
[difftool]
    keepBackup = false
[mergetool "p4merge"]
    path = C:/Program Files (x86)/Perforce/p4merge.exe
    cmd = p4merge.exe \"$BASE\" \"$LOCAL\" \"$REMOTE\" \"$MERGED\"

Answer 4

Check $ git log, copy the SHA-1 ID of the two different commits, and run the git diff command with those IDs. for example:

$ git diff (sha-id-one) (sha-id-two)

Answer 5

If you want to see all changes to the file between the two commits on a commit-by-commit basis, you can also do

git log -u $start_commit..$end_commit -- path/to/file

Answer 6

Here is a Perl script that prints out Git diff commands for a given file as found in a Git log command.

E.g.

git log pom.xml | perl gldiff.pl 3 pom.xml

Yields:

git diff 5cc287:pom.xml e8e420:pom.xml
git diff 3aa914:pom.xml 7476e1:pom.xml
git diff 422bfd:pom.xml f92ad8:pom.xml

which could then be cut and pasted in a shell window session or piped to /bin/sh.

Notes:

1. the number (3 in this case) specifies how many lines to print
2. the file (pom.xml in this case) must agree in both places (you could wrap it in a shell function to provide the same file in both places) or put it in a binary directory as a shell script

Code:

# gldiff.pl
use strict;

my $max  = shift;
my $file = shift;

die "not a number" unless $max =~ m/\d+/;
die "not a file"   unless -f $file;

my $count;
my @lines;

while (<>) {
    chomp;
    next unless s/^commit\s+(.*)//;
    my $commit = $1;
    push @lines, sprintf "%s:%s", substr($commit,0,6),$file;
    if (@lines == 2) {
        printf "git diff %s %s\n", @lines;
        @lines = ();
    }
    last if ++$count >= $max *2;
}

Answer 7

If you want to make a diff with more than one file, with the method specified by @mipadi:

E.g. diff between HEAD and your master, to find all .coffee files:

git diff master..HEAD -- `find your_search_folder/ -name '*.coffee'`

This will recursively search your your_search_folder/ for all .coffee files and make a diff between them and their master versions.

Answer 8

If you have several files or directories and want to compare non continuous commits, you could do this:

Make a temporary branch ("revision" in this example)

git checkout -b revision

Rewind to the first commit target

git reset --hard <commit_target>

Cherry picking on those commit interested

git cherry-pick <commit_interested> ...

Apply diff

git diff <commit-target>^

When you done

git branch -D revision

Answer 9

Just another way to use Git's awesomeness...

git difftool HEAD HEAD@{N} /PATH/FILE.ext

Answer 10

If you want a simple visual comparison on Windows such as you can get in Visual SourceSafe or Team Foundation Server (TFS), try this:

• right-click on the file in File Explorer
• select 'Git History'

Note: After upgrading to Windows 10 I have lost the Git context menu options. However, you can achieve the same thing using 'gitk' or 'gitk filename' in a command window.

Once you call 'Git History', the Git GUI tool will start, with a history of the file in the top left pane. Select one of the versions you would like to compare. Then right-click on the second version and choose either

Diff this -> selected

or

Diff selected -> this

Colour-coded differences will appear in the lower left-hand pane.

Answer 11

All the other responses are more complete, so upvote them. This one is just to remember that you can avoid knowing the id of the recent commit. Usually, I set my self in the branch that I want to compare and run diff tools knowing the old commit uid (You can use other notations):

git checkout master
git difftool 6f8bba my/file/relative/path.py

Also, check this other response here to set the tool you want git open to compare the file: Configuring diff tool with .gitconfig And to learn more about difftool, go to the difftool doc