CODEWITHSUNDEEP
diff
Defman
Defman

Reputation: 81

Generate diff with prefix

I have a file which is not under git control and I need to generate a patch for it. I know I can use diff -Naur file file_new > diff.patch but it will produce something like:

--- file    <timestamp>
+++ file_new    <timestamp>
<diff content>

But I want to get something like git diff does:

--- a/file <timestamp>
+++ b/file <timestamp>
<diff content>

Is there a way to generate this type of patch without using git diff and editing it manually?

Upvotes: 1

Views: 96

Answers (2)

ewaldc
ewaldc

Reputation: 1

The git diff --no-index command provides the capabilities of git diff without the need to have your files/directories added to the git system (e.g. using git add). git diff will by default add a/ and b/ to the source and destination files respectively, hence

git diff --noindex file file_new > diff.patch

should give the requested result.

In addition, the options --src-prefix= and --dst-prefix= allow to change /a and /b in whatever desired. As with regular diff, to create new content from (files in) a directory, you can not use /dev/null as the source, but need an empty directory instead.

mkdir /tmp/empty
git diff --no-index --dst-prefix="b/drivers/net/ethernet/" /tmp/empty mydriver/ >mydriver.patch

will create a patch file that, when executed, generates a new Linux kernel ethernet network driver in the proper drivers/net/ethernet/mydriver directory from the content of the local (development) folder mydriver

Upvotes: 0

Defman
Defman

Reputation: 81

Ok, I created a simple function in my ~/.zshrc file that does it. Hope this would be helpful for someone.

diffgit () {
        local dir_a=a/${$(dirname $1)#pwd}
        local dir_b=b/${$(dirname $1)#pwd}
        mkdir -p ./${dir_a} ./${dir_b}
        cp $1 ./${dir_a}
        cp $2 ./${dir_b}/$(basename $1)
        diff -Naur ${dir_a} ${dir_b}
        rm -rf ./{a,b}
}

Upvotes: 2

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