Remove files not matching regular exception from repo history. Useful for splitting repos.

cleangit.sh

#!/bin/bash
set -e
FOUND="$(find -type f | grep -v '\.git/' | grep -v dart || true)"
if [ "$FOUND" != "" ]; then
    git rm -f --ignore-unmatch $FOUND
fi
# clean submodules
find -type d -exec 'git' 'rm' '{}' ';' 2>/dev/null || true

script.sh

git filter-branch -f --prune-empty -d /dev/shm/scratch \
  --tree-filter $PWD/cleangit.sh \
  --tag-name-filter cat -- --all #>/dev/null