clean up top large files in git commit history

clean_git_history.sh

#!/bin/bash
# INSPIRED BY:
# http://luren5.com/2017/05/11/%E6%8F%90%E4%BA%A4%E5%A4%A7%E6%96%87%E4%BB%B6%E5%AF%BC%E8%87%B4-git-objects-pack%E7%9B%AE%E5%BD%95%E5%BE%88%E5%A4%A7%E8%A7%A3%E5%86%B3%E5%8A%9E%E6%B3%95/

TOP_FILES=top-files
CLEAN_FILES=clean-files

function find_top_files() {
        TOP=$1
        git rev-list --objects --all | \
                grep "$(git verify-pack -v .git/objects/pack/*.idx \
                | sort -k 3 -n | tail -${TOP} | awk '{print$1}')" \
                > "${TOP_FILES}"
}

function clean_files() {
        cat "${TOP_FILES}" | awk '{print $2}' | tr '\n' ' '  \
                >  "${CLEAN_FILES}"

        git filter-branch -f --prune-empty --index-filter \
                "git rm -rf --cached --ignore-unmatch `cat ${CLEAN_FILES}`" \
                --tag-name-filter cat -- --all

        if [[ $? -eq 0 ]]; then
                echo "clean big files successful, push to remote origin (e.g.):"
                echo -e "\n\tgit push origin --force --all"
                rm "${TOP_FILE}" "${CLEAN_FILES}"
        fi
}


if [[  $1 == "-h" ]];
then
        echo "usage:"
        echo -e "\tclean_git_history.sh find_top_files \$TOP"
        echo -e "\tclean_git_history.sh clean_files"
else
        $@
fi