Automating to copy a set of commits from one branch to another

copy_commits.sh

#!/bin/bash

# Prints usage
usage() {                                      
  echo "Usage: $0 -p <project_path> -s <source-branch> -t <target-branch> -f <commit-start> -e <commit-target>" 1>&2 
}

# Prints usage and exit
abnormal_exit() {                              
  usage
  exit 1
}

# Variables for branches, commits and project_path
PROJECT_PATH=""
SOURCE_BRANCH=""
TARGET_BRANCH=""
FROM_COMMIT=""
TO_COMMIT=""



# Getting all the options
while getopts ":p:s:t:f:e:" o; do
    case "${o}" in
        p)
            PROJECT_PATH="${OPTARG}"
            ;;
        s)
            SOURCE_BRANCH="${OPTARG}"
            ;;
        t)
            TARGET_BRANCH="${OPTARG}"
            ;;
        f)
            FROM_COMMIT="${OPTARG}"
            ;;
        e)
            TO_COMMIT="${OPTARG}"
            ;;
        *)
            abnormal_exit
            ;;
    esac
done
shift $((OPTIND-1))

# If one of the options is not set, just abnormal exit
if [ -z "${PROJECT_PATH}" ] || [ -z "${SOURCE_BRANCH}" ] || [ -z "${TARGET_BRANCH}" ] || [ -z "${FROM_COMMIT}" ] || [ -z "${TO_COMMIT}" ]  
then
    abnormal_exit
fi

# Showing all variables, you can uncomment them
echo "Repository Path : $PROJECT_PATH"
echo "Source branch: $SOURCE_BRANCH"
echo "Target branch: $TARGET_BRANCH"
echo "From commit: $FROM_COMMIT"
echo "To commit: $TO_COMMIT"
echo ""

echo "---Starting copying commits---"

# Go to the project path
cd "$PROJECT_PATH"

# Checkout to source branch
echo "Checking out to ${SOURCE_BRANCH}..."
git checkout "$SOURCE_BRANCH"
if ! [[ $? -eq 0 ]]
then
    echo $'\u274c' "ERROR: Failed to checkout to $SOURCE_BRANCH"
    exit 2
fi

# Getting all commits between them inclusive
echo "Getting all commits..."
commits=($(git rev-list "$FROM_COMMIT^..$TO_COMMIT"))


# Now checking out to target branch
echo "Checking out to ${TARGET_BRANCH}..."
git checkout "$TARGET_BRANCH"
if ! [[ $? -eq 0 ]]
then
    echo $'\u274c' "ERROR: Failed to checkout to $TARGET_BRANCH"
    exit 2
fi

# For each commit
for ((i=$((${#commits[@]}-1));i>=0;i--))
do
    echo "Cherry Picking ${commits[i]} ..."
    git cherry-pick "${commits[i]}"
    # If the above command fails, then exit with proper message
    if ! [[ $? -eq 0 ]]
    then
        echo "ERROR: Cherry pick commit with ${commits[i]} failed, exiting..."
        exit 2
    fi
    # Show success message for the copied commit
    echo "DONE: Commit ${commits[i]} copied"
done
# Show success message of all the commits copied
echo "COMPLETED: Cherry pick of ${#commits[@]} commits finished."