date — date and time in the shell

Q: Spaces/colons ended up in a filename

date prints with spaces/: by default (bad for filenames). Use a format: date +%Y%m%d-%H%M%S or %F.

Q: The time is wrong / the wrong timezone

date uses the system timezone. Check/change it via timedatectl; for UTC, use date -u; for another zone once, TZ='Europe/London' date. A drifting clock — NTP is covered in timedatectl.

Q: Month/weekday names are in English but I need Russian

It depends on the locale (LC_TIME). Set the locale you need (see locale): LC_TIME=ru_RU.UTF-8 date '+%A %d %B'.

Q: I need a timestamp in a script's logs

printf '%s %s\n' "$(date -Iseconds)" "message", or use the systemd journal (journalctl adds timestamps itself).

4 min GNU coreutils

The date command: current time, output formats, timestamps for files and logs, date arithmetic.

Cheat sheet

9 commands Printable version

date +%F 2026-06-30 (=%Y-%m-%d)
date +%Y%m%d-%H%M%S a timestamp for filenames
date +%s epoch: seconds since 1970
date -d @1700000000 epoch → human-readable
date -d "yesterday" +%F yesterday
date -d "now + 1 hour" +%T an hour from now
TZ='UTC' date current time in another timezone
date -Iseconds ISO 8601
tar czf "bk-$(date +%F).tgz" /etc a date in a backup's name

Overview

date prints and formats the date/time. In scripts (bash-scripting), it's used for timestamps in backup and log filenames. (System time and timezone are configured with timedatectl.)

bash

date                              # current date/time (local timezone)
date -u                          # in UTC
date +%Y-%m-%d                    # 2026-06-30 (a chosen format)
TZ='America/New_York' date        # show it in another timezone once

Options

/

Below are the main flags of date; the full list is in man date (the +%… format specifiers are a separate topic, see the table under "Recipes").

Option	What it does	Example
`-u` `--utc`	Show the time in UTC instead of the local timezone.	`date -u`
`-d` `--date` string	Show a date parsed from a string (a timestamp, "yesterday", "now + 1 hour"), not the current one.	`date -d "yesterday" +%F`
`-I` `--iso-8601` date\|hours\|minutes\|seconds	Print the date/time in ISO 8601 format.	`date -Iseconds`
`-R` `--rfc-email`	Print the date in RFC 5322 format (for mail and HTTP headers).	`date -R`
`-s` `--set` string	Set the system clock manually; use timedatectl for regular synchronization. dangerous	`sudo date -s "2026-06-30 14:00:00"`
`-f` `--file` datefile	Read and print one date per line from a file.	`date -f dates.txt`

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Recipes

Formats

bash

date +%F                          # 2026-06-30  (=%Y-%m-%d)
date +%T                          # 14:30:05    (=%H:%M:%S)
date +%Y%m%d-%H%M%S               # 20260630-143005 (for filenames)
date +%s                         # Unix timestamp (seconds since 1970)
date -d @1700000000              # timestamp → human-readable
date -Iseconds                   # ISO 8601: 2026-06-30T14:30:05+03:00
date -R                          # RFC 5322 (for mail/HTTP)
date '+%A, %d %B %Y'             # weekday and month spelled out (locale-dependent, see locale)

Specifiers: %Y/%m/%d year/month/day, %H:%M:%S time, %s epoch, %F/%T date/time, %j day of year, %A/%B weekday/month spelled out, %z offset.

Timestamps and arithmetic

bash

# a dated backup name
tar czf "backup-$(date +%F).tar.gz" /etc        # %F = %Y-%m-%d

# relative dates (-d)
date -d "yesterday" +%F
date -d "now + 2 hours" +%T
date -d "2026-01-01 + 30 days" +%F
date -d "last monday" +%F

# difference: via timestamps
echo $(( ($(date -d "2026-07-01" +%s) - $(date +%s)) / 86400 ))   # days until a date

# set the system clock manually (usually unnecessary — there's NTP):
sudo date -s "2026-06-30 14:00:00"        # prefer timedatectl instead

Troubleshooting

Spaces/colons ended up in a filename

date prints with spaces/: by default (bad for filenames). Use a format: date +%Y%m%d-%H%M%S or %F.

The time is wrong / the wrong timezone

date uses the system timezone. Check/change it via timedatectl; for UTC, use date -u; for another zone once, TZ='Europe/London' date. A drifting clock — NTP is covered in timedatectl.

Month/weekday names are in English but I need Russian

It depends on the locale (LC_TIME). Set the locale you need (see locale): LC_TIME=ru_RU.UTF-8 date '+%A %d %B'.

I need a timestamp in a script's logs

printf '%s %s\n' "$(date -Iseconds)" "message", or use the systemd journal (journalctl adds timestamps itself).

Overview

Options

Recipes

Formats

Timestamps and arithmetic

Troubleshooting

Spaces/colons ended up in a filename

The time is wrong / the wrong timezone

Month/weekday names are in English but I need Russian

I need a timestamp in a script's logs

See also