How to Print an ISO-Formatted Date in the Terminal

There are many code snippets online about how to ISO-format a date using the date command in a Linux (or similar) terminal, but some of them are verbose. There’s actually an easy shortcut that isn’t always mentioned.

Here is a quote from the man page for the date utility:

-I[FMT] — Use ISO 8601 output format. FMT may be omitted, in which case the default is ‘date’. Valid FMT values are ‘date’, ‘hours’, ‘minutes’, and ‘seconds’. The date and time is formatted to the specified precision. When FMT is ‘hours’ (or the more precise ‘minutes’ or ‘seconds’), the ISO 8601 format includes the timezone.

Examples of the date Command

If you just need the year, month and day, use -I by itself:

date -I

That will output:

2022-11-05

Including Hours

If you want to include hours, use this form:

date -Ihours

That will output:

2022-11-05T11-07:00

Including Minutes

For minutes:

date -Iminutes

which produces this:

2022-11-05T11:49-07:00

Including Seconds

And finally, with seconds:

date -Iseconds

which produces this:

2022-11-05T11:50:42-07:00

It’s a simple shortcut that can save a bit of time.

For more details, type man date in the terminal.