File-level checkout

Checking out a file is similar to using git reset with a file path, except it updates the working directory instead of the stage. Unlike the commit-level version of this command, this does not move the HEAD reference, which means that you won’t switch branches.

For example, the following command makes foo.py in the working directory match the one from the 2nd-to-last commit:

git checkout HEAD~2 foo.py

Just like the commit-level invocation of git checkout, this can be used to inspect old versions of a project — but the scope is limited to the specified file.

If you stage and commit the checked-out file, this has the effect of “reverting” to the old version of that file. Note that this removes all of the subsequent changes to the file, whereas the git revert command undoes only the changes introduced by the specified commit.

Like git reset, this is commonly used with HEAD as the commit reference. For instance, git checkout HEAD foo.py has the effect of discarding unstaged changes to foo.py. This is similar behavior to git reset HEAD --hard, but it operates only on the specified file.

Continue...