How to ignore changes to a file when committing with Git?

Question

I did search for the solution, yet I believe my situation is a bit different than those I read about.

I am working on a particular branch and made a mistake, having edited a file in a way that is unrelated to the theme of the branch, and now want these changes to not make it into the commit. I do not want to lose these changes, as I will try to commit them on another branch later, one way or another.

I tried git rm --cached but then I see status deleted in my git status - will the file be removed from the repository? I don't want that - I want it to stay unchanged from whatever it is in previous commit on my working branch.

Answer 1

If you do not stage the changes, they will not be part of the commit, something like this:

git status
# On branch development
# Changes not staged for commit:
#   (use "git add <file>..." to update what will be committed)
#   (use "git checkout -- <file>..." to discard changes in working directory)
#
#   modified:   ResearchProposal.tex

Here, ResearchProposal.tex has changes, but they will not be committed by git commit.

If you have two sets of changes in a single file, some that you want to commit and some that you don't, read this.

If you've run git add on a file that you don't want to commit, you need to unstage it:

git reset HEAD <file>

like this:

$ git add ResearchProposal.tex
$ git status
# On branch development
# Changes to be committed:
#   (use "git reset HEAD <file>..." to unstage)
#
#   modified:   ResearchProposal.tex

$ git reset HEAD ResearchProposal.tex 
Unstaged changes after reset:
M   ResearchProposal.tex

$ git status
# On branch development
# Changes not staged for commit:
#   (use "git add <file>..." to update what will be committed)
#   (use "git checkout -- <file>..." to discard changes in working directory)
#
#   modified:   ResearchProposal.tex