Mastering the Linux date Command: Formats, Options, and Real‑World Examples

The date command displays the current date and time in various formats and can also set the system date and time. This article demonstrates common usages and practical examples.

1. Using the –date option to display a date from a string

Provide a static date or time string with -d or --date to have date parse and output it. If no time is given, 00:00:00 is assumed.

$ date --date="12/2/2014"
Tue Dec  2 00:00:00 PST 2014

$ date --date="2 Feb 2014"
Sun Feb  2 00:00:00 PST 2014

$ date --date="Feb 2 2014"
Sun Feb  2 00:00:00 PST 2014

When both date and time are supplied, they are displayed accordingly.

$ date --date="Feb 2 2014 13:12:10"
Sun Feb  2 13:12:10 PST 2014

2. Using the –file option to read date patterns from a file

The -f or --file option processes each line of a file as a date string.

$ cat datefile
Sept 9 1986
Aug 23 1987

$ date --file=datefile
Tue Sep  9 00:00:00 PDT 1986
Sun Aug 23 00:00:00 PDT 1987

3. Using –date for relative dates

Relative expressions such as "next mon" or "3 seconds ago" can be used.

$ date --date="next mon"
Mon May 27 00:00:00 PDT 2013

$ date --date="@5"
Wed Dec 31 16:00:05 PST 1969

$ date --date="@10"
Wed Dec 31 16:00:10 PST 1969

$ date --date="@60"
Wed Dec 31 16:01:00 PST 1969

4. Displaying past dates

Use expressions like "3 seconds ago", "1 day ago", "yesterday", "1 month ago", or "1 year ago".

$ date --date='3 seconds ago'
Mon May 20 21:59:20 PDT 2013

$ date --date="1 day ago"
Sun May 19 21:59:36 PDT 2013

$ date --date="yesterday"
Sun May 19 22:00:26 PDT 2013

$ date --date="1 month ago"
Sat Apr 20 21:59:58 PDT 2013

$ date --date="1 year ago"
Sun May 20 22:00:09 PDT 2012

5. Using –set to set the system date and time

The -s or --set option changes the system clock.

$ date
Sun May 20 20:09:31 PDT 2013

$ date -s "Sun May 20 21:00:00 PDT 2013"
Sun May 20 21:00:00 PDT 2013

$ date
Sun May 20 21:00:05 PDT 2013

6. Using –u to display UTC

Show the date in Coordinated Universal Time with -u, -utc, or -universal.

$ date
Mon May 20 22:07:53 PDT 2013

$ date -u
Tue May 21 05:07:55 UTC 2013

7. Using –r to display a file's last modification time

First, modify the file's timestamp with touch, then use -r to show it.

$ date
Sun May 20 20:25:48 PDT 2013
$ touch datefile
$ date
Sun May 20 20:26:12 PDT 2013
$ date -r datefile
Sun May 20 20:25:57 PDT 2013

8. Various date format options

The +%<format> syntax lets you customize the output. Common options include: date +%a – short weekday name (e.g., Thu) date +%A – full weekday name (e.g., Thursday) date +%b – short month name (e.g., Feb) date +%B – full month name (e.g., February) date +%d – day of month (01‑31) date +%D – date in MM/DD/YY date +%F – date in YYYY‑MM‑DD date +%H – hour (00‑23) date +%I – hour (01‑12) date +%j – day of year (001‑366) date +%m – month (01‑12) date +%M – minute (00‑59) date +%S – second (00‑60) date +%N – nanoseconds (000000000‑999999999) date +%T – time as HH:MM:SS (24‑hour) date +%u – day of week (1‑7, Monday=1) date +%U – week number (Sunday first) date +%Y – full year (YYYY) date +%Z – time‑zone abbreviation (e.g., EDT)