I have made some changes to a file which has been committed in a few times as part of a group of files, but now want to reset/revert the changes on it back to a previous version.
I have done a git log along with a git diff to find the revision I need, but just have no idea how to get the file back to its former state in the past.
Any help is greatly appreciated.
Assuming the commit you want is abcde:
git checkout abcde file/to/restore
The git checkout man page gives more information.
As a side note, I've always been uncomfortable with this command because it's used for both ordinary things (changing between branches) and unusual destructive things (discarding changes in the working directory).
I have to plug EasyGit here, which is a wrapper to make git more approachable to novices without confusing seasoned users. One of the things it does is give more meanings to git revert. In this case, you would say:
eg revert --since your_previous_commit foo/bar foo/baz
I had the same issue just now and I found this answer easiest to understand (commit-ref is the SHA value of the change in the log you want to go back to):
git checkout [commit-ref] [filename]
This will put that old version in your working directory and from there you can commit it if you want.