date (command)

date command allows to print or set the system date and time.

Linux Basic Examples

$date -I or date --iso-8601
2020-01-28

date '+%Y-%m-%d_%H%M'

date --iso-8601=minutes
2020-07-07T08:32+04:00

date --iso-8601=seconds
2014-03-19T16:51:16-0600

$date --rfc-3339=date
2020-01-28

$ date -d now
Wed Aug 18 16:47:31 EDT 2019

$ date -d today
Wed Aug 18 16:47:32 EDT 2019

$ date -d yesterday
Tue Aug 17 16:47:33 EDT 2019

$ date -d tomorrow
Thu Aug 19 16:46:34 EDT 2019

$ date -d sunday
Sun Aug 22 00:00:00 EDT 2019

$ date -d last-sunday
Sun Aug 15 00:00:00 EDT 2019
Other valid date time strings include: last-week, next-week, last-month, next-month, last-year, and next-year.

$ date +%b
Aug 

$date "+%b %d"
Aug 28

$ date +%B
August

$date "+%Y-%m-%d"
2020-10-11

$date "+%F_%H:%M-%Z"
2020-11-22_12:18-UTC

$date --rfc-3339=date
2020-01-28

date -r

macOS Examples

date +%F
2021-07-18

date +%F-%T
2020-08-03-09:14:54

date '+%Y/%m/%d %H:%M:%S'
2021/07/18 16:32:26

date +%s
1655753367

Cisco IOS

• show clock

Activities

1. Read date man page: http://man7.org/linux/man-pages/man1/date.1.html
2. Prepend date output at the beginning of each line: cat your_file.txt | while read i; do echo "$(date) $i"; done

Related

• datetime https://docs.python.org/3/library/datetime.html
• ts (apt install moreutils)

See also

• date, cal, ts
• Linux logging, Cisco IOS logging
• Cisco IOS: show clock

http://man7.org/linux/man-pages/man1/date.1.html