A shell utility to sync your (local) branches with an arbitrary remote

git-sync.sh

#!/usr/bin/env bash

REMOTE_TO_SYNC='upstream' # default remote if none passed
QUIET=false # run in quiet mode
DO_PUSH=false # push to the branches upstream as part of the sync
ONLY_LOCAL=false # Only sync local branches (don't pull down from remote)
SKIP_FETCH=false # Skip the fetch step - really only useful if you know your up to date
Q_FLAG='' # the -q flag for CLI commands - changes to `-q` when running in quiet mode
DEBUG=false

# Our help function
function usage() {
	debug "Usage running"
	echo -e "Syntax `basename $0` [-l] [-d] [-h] [-p] [-q] [-s] [-r remote-name]
	-h Show this help
	-l Only update local branches
	-p Push changes up to the repo
	-q Quiet - minise output
	-s Skip fetching the remote (may cause stale commits to be pushed)
	-r [remote-name] Use this remote to sync with, defaults to ${REMOTE_TO_SYNC}
	-d Debug mode"
	debug "Usage ended"
}

function debug() {
	${DEBUG} && echo -e "$*"
	return 0
}

function quiet() {
	[[ ! ${DEBUG} && ${QUIET} ]] || echo -e "$*"
	return 0
}

# Heavy lifting function to coordinate the parts
function run() {
	debug "Starting run function"
	# store the local branch as we need this later to avoid a git error with forcing branch commits
	local current_branch
	current_branch=$(git rev-parse --abbrev-ref HEAD)

	debug "Determined current branch is ${current_branch}"

	# if the remote exists, we can continue
	if find_remote `git remote`; then
		debug "Found remote ${REMOTE_TO_SYNC}"

		# Fetch the remote if required
		if ! ${SKIP_FETCH}; then
			quiet echo "Fetching remote"
			git fetch "${REMOTE_TO_SYNC}"
		else
			debug "Skipping fetch"
		fi

		# populate the global BRANCHES var
		get_branches_to_sync

		debug "Going through branches to sync:\n" ${BRANCHES}
		# go through all the candidate branches and sync them if needed
		for branch in ${BRANCHES[@]}; do
			debug "Checking branch ${branch}"
			# If we want to sync all branches OR check a branch exists locally
			if  ! ${ONLY_LOCAL} || branch_exists_locally "${branch}"; then
				quiet "Resetting branch ${branch}"
				# If the branch is currently checkedout we have to use git reset
				if [[ "${current_branch}" == "${branch}" ]]; then
					debug "Syncing current branch, using reset method"
					git reset -q --hard "${REMOTE_TO_SYNC}/${branch}"
				else
					debug "Reseting ${branch} to ${REMOTE_TO_SYNC}/${branch}"
					# force the branch name to point to the remote ref
					git branch -f --no-track "${branch}" "${REMOTE_TO_SYNC}/${branch}"
				fi
				# Push up to the default remote if needed
				if [ ${DO_PUSH} ]; then
					ORIGIN=$(git config --get branch."${branch}".remote)
					if [ -z "${ORIGIN}" ]; then
						ORIGIN='origin'
					fi
					debug "Pushing ${branch} to origin: ${ORIGIN}"
					git push ${Q_FLAG} -f "${ORIGIN}" "${branch}":"${branch}"
				else
					debug "Skipping push"
				fi
			else
				debug "Skipping branch"
			fi
		done
		debug "All branches evaluated"
		return 0
	else
		echo "Couldn't find remote: ${REMOTE_TO_SYNC}"
		return 1
	fi
}

# Confirm the remote is in a list of passed remotes
function find_remote() {
	debug "Looking for remote ${REMOTE_TO_SYNC}"
	local e
	for e in "$@"; do
		[[ "$e" == "$REMOTE_TO_SYNC" ]] && debug "Remote found" && return 0;
	done
	debug "Remote not found"
	return 1
}

# Get the name of all the branches on the remote
function get_branches_to_sync() {
	quiet "Getting branches"
	BRANCHES=$(git branch -r | grep -e "^ *${REMOTE_TO_SYNC}\/" | sed "s/ *${REMOTE_TO_SYNC}\///")
}

# Configm the passed branch name exists locally
function branch_exists_locally() {
	debug "Checking if $1 exists locally"
	if [[ ! ${LOCAL_BRANCHES} ]]; then
		debug "Finding local branches"
		LOCAL_BRANCHES=$(git branch | sed 's/\** *//')
		debug "Found ${LOCAL_BRANCHES}"
	fi
	for e in ${LOCAL_BRANCHES[@]}; do
		[[ "$e" == "$1" ]] && debug "Found branch $e locally" && return 0
	done
	debug "Didn't find branch $1 locally"
	return 1
}

# Handle the CLI params
while getopts "dhpqlsr:" OPTION; do
	case ${OPTION} in
		r ) REMOTE_TO_SYNC="$OPTARG"
			debug "Setting remote to ${OPTARG}"
			;;
		p ) DO_PUSH=true
			debug "Enabling push to origin"
			;;
		q ) QUIET=true
			Q_FLAG='-q'
			debug "Entering quiet mode"
			;;
		l ) ONLY_LOCAL=true
			debug "Only updating local branches"
			;;
		s ) SKIP_FETCH=true
			debug "Skipping fetch"
			;;
		d ) DEBUG=true
			debug "Entering debug mode"
			;;
		h ) usage
			debug "Running help"
			exit 0
			;;
	esac
done

run
exit $?