Replays a git history, passing the repository at each state to a given script

gistfile1.sh

#!/bin/bash

# Takes a repository and script from the command line
# and executes the script for each git log entry in reverse chronological order

# Use temporary files of the following format
TMP_TEMPLATE="/tmp/gitreplay-XXXXXXXX"

# Validate command line parameters
if [ -z $1 -o -z $2 ]; then
  echo "Usage: gitReplay.sh REPOSITORY SCRIPT"
  exit
fi

if [ ! -x $2 ]; then
  echo "'$2' does not exist as an executable file"
  exit
fi

REPOSITORY=$1
SCRIPT=$2

# Generate and move to a temporary folder
tmp_loc=`mktemp -d $TMP_TEMPLATE`
pushd $tmp_loc > /dev/null

# Checkout the repository, and bail out if it fails
git clone $REPOSITORY . 2>&1
if [ $? -ne 0 ]; then
  echo "Could not checkout repository"
  popd > /dev/null
  exit;
fi

# Determine all the hashes of the repository history
hashes=`git log --reverse --pretty=format:%H`

# For every hash, move to that revision and pass it to the repository
index=0
for hash in $hashes; do
  git checkout $hash
  bash $SCRIPT $hash $index $tmp_loc

  if [ $? -ne 0 ]; then
    echo "Early terminating based on script return code"
    break
  fi

  let index=$index+1
done

popd > /dev/null
rm -rf $tmp_loc