Number of Commits between two Commitishes

Question

How can I find the number of commits between two commitishes in git?

Additionally, is there some way that I could do the same with any project on GitHub (using the UI, not the API)?

Answer 1

$ git log 375a1..58b20 --pretty=oneline | wc -l 

Specify your start commit followed by your end commit, and then count the lines. That should be the count of commits between those two commit ranges. Use the --pretty=oneline formatting so that each commit takes up a single line.

Note that using two dots (375a1..58b20) is different than using three dots (375a1...58b20); see What are the differences between double-dot “..” and triple-dot “…” in Git commit ranges? for more information about this and to figure out which one you want to use.

As for the GUI in GitHub, I don't know of a way to accomplish this same task. But that should be trivial, as the above is the possible way to do it directly using Git and Bash.

Answer 2

Before I give you an answer, consider this commit graph:

        o -----------        /             \ ... - A - o - o - o - B        \         /         o ----- o 

Each o represents a commit, as do A and B (they're just letters to let us talk about specific commits). How many commits are there between commits A and B?

That said, in more linear cases, just use git rev-list --count A..B and then decide what you mean by "between" (does it include B and exclude A? that's how git rev-list --count will behave). In branchy cases like this, you'll get all the commits down all the branches; add --first-parent, for instance, to follow just the "main line".

(You also mentioned "commitish", suggesting that we might have annotated tags. That won't affect the output from git rev-list, which only counts specific commits.)

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Edit: Since git rev-list --count A..B includes commit B (while omitting commit A), and you want to exclude both end-points, you need to subtract one. In modern shells you can do this with shell arithmetic:

count=$(($(git rev-list --count A..B) - 1)) 

For instance:

$ x=$(($(git rev-list --count HEAD~3..HEAD) - 1)) $ echo $x 2 

(this particular repo has a very linear graph structure, so there are no branches here and there are two commits "between" the tip and three-behind-the-tip). Note, however, that this will produce -1 if A and B identify the same commit:

$ x=$(($(git rev-list --count HEAD..HEAD) - 1)) $ echo $x -1 

so you might want to check that first:

count=$(git rev-list --count $start..$end) if [ $count -eq 0 ]; then     ... possible error: start and end are the same commit ... else     count=$((count - 1)) fi