Purge Git History (for Repositories without Submodules)

git-purge-history.sh

#!/bin/sh
# Purge Git history (for repositories without submodules)
# Useful for reducing the size of a repository when history is no longer needed
# Helpful also when needing to remove file(s) from Git history

# SUSE Bash - https://documentation.suse.com/sles/12-SP4/html/SLES-all/cha-adm-shell.html
#  - General shell scripting - https://www.shellscript.sh/

# ** IMPORTANT NOTE: NOT FOR REPOSITORIES WITH SUBMODULES ** #

# Based in part on the following:
#  - https://gist.github.com/stephenhardy/5470814?permalink_comment_id=2225724#gistcomment-2225724
#  - https://stackoverflow.com/a/71878364
#  - https://stackoverflow.com/q/9683279
#    ~ The "git gc --aggressive --prune=all" options did not seem to work.  Try with "git push --mirror"?
#    ~ https://stackoverflow.com/q/2116778

if [ ! -e .git/config ] ; then
  echo "Command must be executed from the root of a Git repository"
  exit
fi

# Backup the Git folder to a temp location
GIT_TEMP_DIR=`mktemp -d git-purge-temp_XXXXXXX --tmpdir`
mv .git "$GIT_TEMP_DIR/.git"

# Reinitialize git repository
git init

# Restore the Git configuration file
cp --preserve=all "$GIT_TEMP_DIR/.git/config" ".git/config"

# Commit the current contents
git add .
git commit -m "Reset commit"

# Force-push a mirror of the reset repository
git push --mirror --force

# Cleanup backup files and folders
rm -rf "$GIT_TEMP_DIR"