A basic SEMVER release version manager in python

release.py

#!/usr/bin/python
import sys
import os.path

def display_usage():
    print """USAGE:
    release.py [major|minor|patch|init]"""
    sys.exit()

def parse_version(version):
    version_info = version.replace("v", "").split('.')
    return {
        "major" : int(version_info[0]),
        "minor" : int(version_info[1]),
        "patch" : int(version_info[2])
    }

def to_version_string(version):
    return "v{}.{}.{}".format(version['major'], version['minor'], version['patch'])

FILE_NAME = ".release_version"

if(len(sys.argv)) != 2:
    display_usage()

increment = sys.argv[1]

if(increment == 'init'):
    with open(FILE_NAME, "w") as version_file:
        version_file.write("v0.1.0")

elif(os.path.isfile(FILE_NAME)):
    with open(FILE_NAME, "r+w") as version_file:
        current_version = parse_version(version_file.read().replace('\n', ''))

        if(increment in current_version):
            current_version[increment] = current_version[increment]+1

        updated_version = to_version_string(current_version)
        version_file.seek(0)
        version_file.write(updated_version)
        print updated_version
else:
    display_usage()