How add or change a file but is ignored by git

gistfile1.txt

git init
touch test.php
git add test.php
git commit -m "initial commit"

# any command or script to add or change a file but is ignored by git
# example: add debug.php and alter file -> echo -n "testing..." >> test.php
any-command-to-edit-or-create-patch-files

ls
-> test.php debug.php

# Now git status to ignore the added and changed files.
git status
-> nothing to commit (working directory clean)