How to replace a string in a whole Git history?

Question

I have one of my passwords commited in probably few files in my Git repo. Is there some way to replace this password with some other string in whole history automatically so that there is no trace of it? Ideally if I could write simple bash script receiving strings to find and replace by and doing whole work itself, something like:

./replaceStringInWholeGitHistory.sh "my_password" "xxxxxxxx"

Edit: this question is not a duplicate of that one, because I am asking about replacing strings without removing whole files.

Answer 1

First, find all the files that could contain the password. Suppose the password is abc123 and the branch is master. You may need to exclude those files which have abc123 only as a normal string.

git log -S "abc123" master --name-only --pretty=format: | sort -u

Then replace "abc123" with "******". Suppose one of the files is foo/bar.txt.

git filter-branch --tree-filter "if [ -f foo/bar.txt ];then sed -i s/abc123/******/g foo/bar.txt;fi"

Finally, force push master to the remote repository if it exists.

git push origin -f master:master

I made a simple test and it worked but I'm not sure if it's okay with your case. You need to deal with all the files from all branches. As to the tags, you may have to delete all the old ones, and create new ones.