Update your WordPress git submodule quickly with this script.

_README.md

Update WordPress Script

Use this script to quickly update to the latest version of WordPress.

Requirements:

1. WordPress should be located in subdirectory of root (i.e. site-root/wp).
2. Requires WordPress to be a git submodule.

update-wp.sh

#!/bin/bash

# Use this script to update WordPress to the latest version. Keep in mind that
# this script will commit the new version automatically; therefore, only use
# this script for quick updates to production, not development.

# Change to WordPress directory.
cd "$(git rev-parse --show-toplevel)"/wp

# Get the current tag and run a conditional to see if we are on a tag or not.
current_tag=$( git name-rev --tags --name-only $(git rev-parse HEAD) )

# No tag? Bail.
if [[ $current_tag == 'undefined' ]]; then
	# Update complete message.
	echo "You are not currently on any tag."

	exit
fi

# We've made it this far, let's perform the update.

# Fetch the repo and tags.
git fetch && git fetch --tags

# Get the latest tag.
latest_tag=$( git tag | tail -1 )

# If the latest tag is greater than the current tag, perform updates. Otherwise
# no updates are needed and we can bail.
if [[ $latest_tag > $current_tag  ]]; then
	# Clean and update WordPress.
	git clean -f -d && git reset --hard HEAD && git checkout master && git pull && git fetch --tags && git checkout $latest_tag && cd "$(git rev-parse --show-toplevel)"

	# Commit update.
	git add wp && git commit -m "Update WordPress to $latest_tag" && git push

	# Update complete message.
	echo "Updated complete. WordPress is now at $latest_tag."

	exit
else
	# Update complete message.
	echo "No update required. WordPress is at $current_tag."

	exit
fi