What does the caret (^) character mean in Git?

Question

HEAD^ means the first parent of the tip of the current branch.

Remember that git commits can have more than one parent. HEAD^ is short for HEAD^1, and you can also address HEAD^2 and so on as appropriate.

You can get to parents of any commit, not just HEAD. You can also move back through generations: for example, master~2 means the grandparent of the tip of the master branch, favoring the first parent in cases of ambiguity. These specifiers can be chained arbitrarily , e.g., topic~3^2. See related answer to What’s the difference between HEAD^ and HEAD~ in Git?

For the full details, see the “Specifying Revisions” section of git rev-parse --help.

It means "parent of". So HEAD^ means "the parent of the current HEAD". You can even chain them together: HEAD^^ means "the parent of the parent of the current HEAD" (i.e., the grandparent of the current HEAD), HEAD^^^ means "the parent of the parent of the parent of the current HEAD", and so forth.

The ^ (caret) can also be used when specifying ranges.

To exclude commits reachable from a commit, a prefix ^ notation is used. E.g. ^r1 r2 means commits reachable from r2 but exclude the ones reachable from r1.

<rev>

Include commits that are reachable from (i.e. ancestors of) .

^<rev>

Exclude commits that are reachable from (i.e. ancestors of) .

Here's a visual explanation. Suppose you have a history like so:

                      master  
  ... <- B <- C <- D
             /
... <- E <- F
              feature

When feature was merged into master, C was created with two ancestors. Git assigns these ancestors numbers. The mainline ancestor B is assigned 1 and the feature ancestor F is assigned 2.

Thus C^1 refers to B and C^2 refers to F. C^ is an alias for C^1.

You would only ever use <rev>^3. if you had performed a merge of three branches.

The caret refers to the parent of a particular commit. E.g. HEAD^ refers to the parent of the current HEAD commmit. (also, HEAD^^ refers to the grandparent).

The carat represents a commit offset (parent). So for instance, HEAD^ means "one commit from HEAD" and HEAD^^^ means "three commits from HEAD".

The (^) gets the parent source of the command i.e. HEAD^ will get the parent of HEAD.