How get git commit hash by it number (--count)

Question

I get a position of commit by command

git rev-list HEAD --count

For example, output is 1164. I want checkout to this commit number. How can I do this? I think, need get hash of this commit and checkout to commit by it hash.

Answer 1

Here's another solution:

git rev-list HEAD --reverse | nl | grep <your build number>

git rev-list HEAD --reverse prints out all the commit hashes from oldest to newest. nl prefixes each line with a line number (effectively the count). And finally, good ol' grep filters to just the line you want.

You could further refine this to just the commit hash with awk:

git rev-list HEAD --reverse | nl | grep <your build number> | awk '{print $2}'

or take it to the next level with a git alias:

git config --global alias.build-number '!f() { git rev-list HEAD --reverse | nl | grep $1 | awk '"'"'{print $2}'"'"'; }; f'

Alias usage:

git build-number <your build number>

That quoting madness in the git config command above is explained here: https://stackoverflow.com/a/1250279/320737

Answer 2

By adding --count to the git rev-list command line you tell it to not display the revisions list but only the number of revisions it would display without the --count argument.

Basically git rev-list HEAD --count and git rev-list HEAD | wc -l produce the same output (the number of lines in the output of git rev-list HEAD).

---

The answer to your question depends on what exactly do you mean by "commit #1164".

If you count the commits as they are listed by rev-list then the first commit is the current commit (aka HEAD) and commit #1164 is the oldest commit that is reachable starting from HEAD. To get its hash, don't tell git rev-list to display the count but let it display the revisions (it displays their hashes) and pipe its output to tail -1 to get the last hash in the list:

git rev-list HEAD | tail -1

But please note that by adding a new commit to the current branch, the numbering will change and commit #1164 will be a different commit.

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If you count the commits in chronological order, commit #1 being the first commit created in the repository then commit #1164 is the current commit. In this case you don't even need to use git rev-list (it walks the entire repository but you don't need this). It's enough to use:

git rev-parse HEAD

to get the hash of the current commit (HEAD).

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Either way, the number you produced (1164) does not have any relevance to Git and it is not associated in any way with any commits. If you check out a different branch that has at least 1164 commits and follow the same procedure you get a different commit as commit #1164.

Answer 3

Thanks all for yours answers, but it not what I was looking for. I know that use git --count it`s not good idea, but at the moment we mark our bilds by this method.

I write little bash snippet, that doing what I need.

#!/bin/bash
SEARCH=$1
LAST=$(git rev-list HEAD --count)
DIFF=$((LAST-SEARCH))
git rev-list --skip=$DIFF --topo-order HEAD | head -n1

Where SEARCH it is --count of commit that you what to search.