Increment BUILD_VERSION property in an xcconfig file (useful when you have multiple targets that all need to have the same build version, such as with a watchOS 2 app and your continuous deployment system needs to increment the build version)

update_xcconfig_build_version.rb

# Assumes build version in xcconfig is defined as the following, where no spaces, spaces and/or tabs are allowed:
# BUILD_VERSION = 1.2.3.4

filename = "sample.xcconfig"
build_version_property = "BUILD_VERSION"
new_version_string = ""


lines = IO.readlines(filename)

for line in lines

	arr = line.gsub(/\s+/m, '').strip.split("=")

	if arr.count == 2 && arr[0] == build_version_property

		# Extract the build number from this string, increment its last value, and then rewrite line

		# Remove all whitespace from current line and split on '='

		version_string = arr[1]

		version_arr = version_string.split(".")

		if version_arr.count == 4 

			# Get build number string, increment build number and recompose overall build version string

			build_version = version_arr[3]

			numeric_build_version = build_version.to_i

			numeric_build_version += 1

			new_version_string = "#{version_arr[0]}.#{version_arr[1]}.#{version_arr[2]}.#{numeric_build_version}"

		else
			#put "Error: BUILD_VERSION must contain 4 values: major.minor.patch.build!"
		end

		break

	end
end

# Output the new version string to be used in the archive filename, etc.

if new_version_string == ""
	
	puts ""

else

	puts "#{new_version_string}"

	# Update xcconfig file
	
	f = File.open(filename, "w")

	for line in lines
	
		arr = line.gsub(/\s+/m, '').strip.split("=")
		
		if arr.count == 2 && arr[0] == build_version_property

			# Note that when we update this line in the xcconfig, it will lose any additional white spacing it might have had.

			f.puts("#{build_version_property} = #{new_version_string}")

		else

			f.puts(line)

		end

	end

	f.close

end