Untrack existing Git file

How would you stop tracking future changes in an existing Git repository file, but do not want to delete that file from the repository?
git rm --cached is the command that’ll do the trick, however, it needs to be done in following way.

Syntax

git rm --cached filename

Steps with example

Update the .gitignore file to include the filename, stage and commit .gitignore file.

ak@--mac git-useful-commands % echo "db.config" >> .gitignore
ak@--mac git-useful-commands % git add .gitignore 
ak@--mac git-useful-commands % git commit -m "Update .gitignore"

Now make some edits and stage the file that you want to remove from future tracking. Later, remove the file from staging and commit it

ak@--mac git-useful-commands % git add db.config 
ak@--mac git-useful-commands % git rm --cached db.config
ak@--mac git-useful-commands % git commit -m "untrack db config file"

Now, the file will remain in the repository, but future changes won't be tracked.

Happy Coding!