Finding when a line was deleted

git blame is a very useful tool for finding out when a line in a file was added or changed. I mostly use it through Magit, and it’s helped identify when a regression was introduced on many occasions. However, sometimes it’s useful to know the opposite: given a line in an older commit, when was it later modified or deleted?

Fortunately, there’s git blame --reverse, which works like:

git blame --reverse <old commit>..<new commit> <file>

For each line corresponding to file state in <old commit>, it reports last commit between <old commit> and <new commit> where the line remained unmodified.

Consider the following example with file test.txt:

In 2686bf3 we add A:

A

In 0bc06ca, we add B:

A
B

In 6983da5, we add C:

A
B
C

And in c7e761c, we delete B:

A
C

Suppose we want to find the commit that deleted B. We can start at 0bc06ca (or any commit where B is still present) and stop at HEAD¹:

git blame --reverse 0bc06ca..HEAD test.txt

This gives the following:

c7e761c7 (Tianxiang Xiong 2025-06-19 12:48:12 -0700 1) A
6983da5c (Tianxiang Xiong 2025-06-19 12:48:03 -0700 2) B

We can see that 6983da5c was the last commit where B was unmodified. The next commit would be the one to delete it. We can find that commit with git log (or better yet, git log --reverse, so older commits are shown first and we don’t need to scroll):

git log --reverse 6983da5c^..HEAD

commit 6983da5c7bca0c2b1a81f8611ba1eeeb83b7f9fd
Author: Tianxiang Xiong <tianxiang.xiong@gmail.com>
Date:   Thu Jun 19 12:48:03 2025 -0700

    Add C

commit c7e761c7c87540f69e2cae8749b0e3a89c69a794 (HEAD -> master)
Author: Tianxiang Xiong <tianxiang.xiong@gmail.com>
Date:   Thu Jun 19 12:48:12 2025 -0700

    Delete B

So we see that c7e761c is the one that deleted B.