如何获取上一次提交的SHA编号？

Question

For my research I need few data, one of which is the SHA number for the previous commit ie if I give a particular commit number/SHA number, I should be able to get the SHA number before it.

Help me with the git command to get the same.

Answer 1

The command to translate any specifier into a hash ID is git rev-parse .

The syntax that means "find the parent commit of a commit" is from gitrevisions , and is commit ^ or commit ~ —use whichever you prefer to type. The commit part can be nearly any valid commit specifier, including a branch name, another commit hash ID, the special name HEAD , or another one of these suffixed expressions.

Hence:

HEAD^

is the parent of HEAD , and:

HEAD^^

is the parent of HEAD^ , and so on.

The tilde syntax is actually a compressed version of many hat suffixes, so:

HEAD~5

means the same thing as:

HEAD^^^^^

If the number after the tilde is missing, Git assumes you meant 1 .

What all this means, put together, is that:

git rev-parse HEAD^

(or HEAD~ ) will get you the actual hash ID. But you can just write HEAD^ or HEAD~ instead, with any normal Git command. Similarly, if 1234567 is a valid shortened commit hash ID, you can write 1234567^ or 1234567~1 to refer to its parent commit.

(Commits that are merge commits have two or more parents, in which case there is more syntax available to extract each parent one at a time, or to refer to all parents. Again, see gitrevisions for details.)

Answer 2

git rev-list --parents -n 1 SOME_COMMIT将为您提供您指定的提交的SHA，然后是其父级的SHA。

Answer 3

git log --format="%H" -n 1 <commit>~仅输出哈希值（％H），并将输出限制为提交父项（〜）的1个条目（而不显示所有祖先）。