SHELL

git remove files from old commits

git filter-branch --index-filter 
'git rm --cached --ignore-unmatch path/to/mylarge_file' 
--tag-name-filter cat -- --all

filter-branch keeps backups too, so the size of the repo won't decrease immediately unless you expire the reflogs and garbage collect:

rm -Rf .git/refs/original       # careful
git gc --aggressive --prune=now # danger

git show which commits deleted file

git log --full-history  -- [file path]