Find the checksum of the most recent commit in a GitHub repository

get_last_commit.py

#!/usr/bin/env python3
"""
Get the sha sum of the last commit on the master branch
of a github repository.

Suitable for using in shell scripts: i.e.
last_commit=`python3 ~/bin/get_last_commit.py $url` will
assign the sha sum of the last commit found at $url
to $last_commit. In this case (for bash at least)
print(shasum) will not actually print the sha sum to the 
console.
"""
import json
import requests
import sys

main_url = sys.argv[1]
protocol, path = main_url.split('//')
components = path.split('/')
api_path = 'api.' + components[0] + '/repos/' + '/'.join(components[1:]) + '/commits/master'
api_url = protocol + '//' + api_path

commit = requests.get(api_url)
if commit.ok:
    shasum = json.loads(commit.text)['sha']
    print(shasum)
    sys.exit(0)
else:
    sys.exit(1)