Simple bash script for truncating git repo history

git-­truncate.sh

#!/bin/bash
 
#   Usage:
#   ./git-truncate.sh SHA1
#       Removes all the history prior to commit "SHA1"
 
git checkout --orphan temp $1
git commit -m "Truncated history of git repo"
git rebase --onto temp $1 master
git branch -D temp
 
# Optional, may take awhile
git prune --progress
git gc --aggressive