Pipfile-CLI: Command line interface around Pipfile operations

Pipfile-CLI is a command line interface around the Pipfile API. It allows you to interact with a Pipfile without Pipenv.

The command line interface’s design is based on the three transformation functions, as described by Sam Boyer in his So you want to write a package manager piece:

• The user edits Pipfile to add and/or remove packages.
• lock resolves the abstract dependency set specified in Pipfile, and write the resulting concrete dependency set into Pipfile.lock.
• sync installs the concrete dependency set specified by Pipfile.lock into the current environment (with pip).

Only sync is implemented at the present time.