#!/bin/sh

CHECKSUM=$1
FILE=$2

if [[ -z "$CHECKSUM" ]]; then
    echo "Usage: $0 md5 file"
    exit 1
elif [[ -z "$FILE" ]]; then
    echo "Usage: $0 md5 file"
    exit 1
fi

# Check if valid git repo
ROOT=$(git rev-parse --show-toplevel)
if [[ $? -ne 0 ]]; then
    echo "Not a valid git repo."
    exit 1
fi
cd "$ROOT"

# git revision for file
REVS=`git log --pretty=%H -- $FILE`

# check each revision for checksum
for rev in $REVS; do
    git show $rev:$FILE > _file_to_check
    # if you are on a Linux system, change md5 to md5sum
    if [[ -n `md5sum _file_to_check | grep $CHECKSUM` ]]; then
        echo $rev
    fi
    rm _file_to_check
done