biff

A simple utility for doing datetime arithmetic, parsing, and formatting. tldr-pages

On several platforms

Several platforms

Print the current time in a format of your choosing

biff time fmt --format rfc3339 nowIdentify

Print multiple relative times in one command

biff time fmt --format '%c' now -1d 'next sat' 'last monday' '9pm last mon'Identify

Print the current time in another time zone and round it the nearest 15 minute increment

biff time in Asia/Bangkok now | biff time round --increment 15 --smallest minuteIdentify

Convert a time between two different time zone

TZ='Japan' biff time in America/New_York 02:30Identify

Print a past or future time relative to current time

biff time add -1d nowIdentify

Add a complex duration to the current time

biff time add '1 week, 12 hours ago' nowIdentify

Find the duration since a date in the past and round it to the desired precision

biff span since 2025-01-20T12:00 --largest yearIdentify

Find timestamps in a log file and reformat them into your local time in place

biff tag lines /tmp/access.log | biff time in system | biff time fmt --format '%c' | head --lines 3 | biff untag --substitute