Biff is a command line datetime Swiss army knife

Biff

A command line tool for datetime arithmetic, parsing, formatting and more.

Dual-licensed under MIT or the UNLICENSE.

Documentation

The user guide should be your first stop for understanding the high level concepts that Biff deals with. Otherwise, consult biff --help or biff <sub-command> --help for more specific details.

Alternatively, there is a comparison between other similar tools that might give you a quick sense of what Biff is like.

Brief Examples

Print the current time:

$ biff Sat, May 10, 2025, 8:02:04 AM EDT

Tip If you get output like 2025 M05 10, Mon 08:02:04 instead, that's because you likely don't have locale support support configured. That requires setting BIFF_LOCALE and using a GitHub release binary or building Biff with the locale feature enabled.

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