Git Update & Install with PGP and ShaSums

git-validated-install.sh

git-validated-install()
{
	# Pull the latest version of Git from https://git-scm.com html
	if [ -z "$latest_git_version" ]; then
	    if [ "`uname`" == "Darwin" ]; then 
	        sed_regexp="-E"; 
	    else 
	        sed_regexp="-r"; 
	    fi
	    latest_git_version=$(curl https://git-scm.com/ 2>&1 | grep '<span class="version">' -A 1 | tail -n 1 | sed $sed_regexp 's/ *//')
	fi

	# Get the version of Git locally 
	local_git_version=$(git --version)
	local_git_version=$($local_git_version |cut -d " " -f3)

	echo "Latest Git Version: $latest_git_version"
	echo "Local Git Version: $local_git_version"

	if [[ "$local_git_version" == "$latest_git_version" ]]; then
		echo "Git is already up to date."
	else
		# Fetch tar
		curl -O https://kernel.org/pub/software/scm/git/git-2.10.1.tar.gz
		
		# Fetch checksums
		curl -O https://kernel.org/pub/software/scm/git/sha256sums.asc
		
		# Fetch GPG sig from keyserver network:
		gpg --keyserver keyserver.ubuntu.com --recv-keys 0x632D3A06589DA6B1
		
		# Fetch GPG sig from keyserver network:
		signature=$(gpg --verify sha256sums.asc | grep "Good signature")
		# *Caveat: this trusts the keyserver network and the provenance of the KeyID from the GPG signature

		if [ $signature -eq 0 ]; then
			echo "Signature failed!"
			return 1
		fi

		# Install openssl
		brew install openssl

		# Compare checksums
		cksum=$(shasum -a 256 ./git-$latest_git_version.tar.gz  | cut -d" " -f1)
		refsum=$(grep git-$latest_git_version.tar.gz ./sha256sums.asc | cut -d" " -f1)

		if [ "$refsum" != "$cksum" ]; then
			echo "Bad checksum"
			return 1
		fi

		# Uncompressing tar archive
		tar xzf "git-$latest_git_version.tar.gz"
		
		cd "git-$latest_git_version"

		# Downloading gettext
		brew install gettext

		# Add symlinks
		export LDFLAGS=-L/usr/local/opt/gettext/lib
		export CPPFLAGS=-I/usr/local/opt/gettext/include

		# Define two environment variables
		export CPATH="/usr/local/opt/openssl/include:/usr/local/opt/gettext/include"
		export LIBRARY_PATH="/usr/local/opt/openssl/lib:/usr/local/opt/gettext/lib"

		brew link gettext --force

		# Clean up files
		cd ..
		rm -r -f "git-$latest_git_version"
		rm "git-$latest_git_version.tar.gz"
		rm sha256sums.asc

		make
	fi
}

hii