DATE(1) | General Commands Manual | DATE(1)

# NAME

`date` — display or set date and time

# SYNOPSIS

`date` | [`-aju`] [`-f` pformat] [`-r` seconds] [`-z` output_zone] [`+`format] [[[[[[cc]yy]mm]dd]HH]MM[.SS]]

# DESCRIPTION

When invoked without arguments, the `date` utility displays the current date and time. Otherwise, depending on the options specified, `date` will set the date and time or print it in a user-defined way.

Changing the system date has some risks, as described in settimeofday(2). Only the superuser may change the date.

The options are as follows:

`-a`
  Use the adjtime(2) call to gradually skew the local time to the desired time rather than just hopping.
`-f` pformat
  Parse the specified time using strptime(3) with a format string of pformat.
`-j`
  Parse the provided date and time and display the result without changing the clock.
`-r` seconds
  Print out (in specified format) the date and time represented by seconds from the Epoch.
`-u`
  Display or set the date in UTC (Coordinated Universal) time.
`-z` output_zone
  Just before printing the time, change to the specified timezone; see the description of `TZ` below. This can be used with `-j` to easily convert time specifications from one zone to another.

An operand with a leading plus sign (‘+’) signals a user-defined format string which specifies the format in which to display the date and time. The format string may contain any of the conversion specifications described in the strftime(3) manual page, as well as any arbitrary text. A newline (‘`\n`’) character is always output after the characters specified by the format string. The format string for the default display is:

    %a %b %e %H:%M:%S %Z %Y

If an operand does not have a leading plus sign, it is interpreted as a value for setting the system's notion of the current date and time. The canonical representation for setting the date and time is:

ccyy
  Year. If yy is specified, but cc is not, a value for yy between 69 and 99 results in a cc value of 19. Otherwise, a cc value of 20 is used.
mm
  Month: a number from 1 to 12.
dd
  Day: a number from 1 to 31.
HH
  Hour: a number from 0 to 23.
MM
  Minute: a number from 0 to 59.
SS
  Second: a number from 0 to 60 (permitting a leap second), preceded by a period.

Everything but the minute is optional.

Time changes for Daylight Saving Time, standard time, leap seconds, and leap years are handled automatically.

# ENVIRONMENT

`TZ`
  The time zone to use when parsing or displaying dates. It is normally specified as a pathname relative to /usr/share/zoneinfo, though see tzset(3) for more information. If this variable is not set, the time zone is determined based on /etc/localtime, which the administrator adjusts using the `-l` option of zic(8).

# FILES

/var/log/wtmp
  record of date resets and time changes
/var/log/messages
  record of the user setting the time

# EXIT STATUS

The `date` utility exits 0 on success, and >0 if an error occurs.

# EXAMPLES

Display the date using the specified format string:

    $ date "+DATE: %Y-%m-%d%nTIME: %H:%M:%S"
    DATE: 1987-11-21
    TIME: 13:36:16

Set the date to June 13, 1985, 4:27 PM:

`# date 198506131627`

Set the time to 2:32 PM, without modifying the date:

`# date 1432`

If the mailing list server located in California is being taken offline at 5:45 AM, work out what time it will be locally, here in Tokyo:

`$ TZ=America/Los_Angeles date -j -z Asia/Tokyo 0545`

# SEE ALSO

adjtime(2), gettimeofday(2), strftime(3), utmp(5), ntpd(8), rdate(8)

# STANDARDS

The `date` utility is compliant with the IEEE Std 1003.1-2008 (“POSIX.1”) specification.

The flags [`-afjrz`], as well as the conversion specifiers ‘`%F`’, ‘`%G`’, ‘`%g`’, ‘`%k`’, ‘`%l`’, ‘`%R`’, ‘`%s`’, ‘`%v`’, and ‘`%+`’, are extensions to that specification.

This implementation requires the traditional BSD date format, [[[[[cc]yy]mm]dd]HH]MM[.SS], which differs from the X/Open System Interfaces option of the IEEE Std 1003.1-2008 (“POSIX.1”) specification.

# HISTORY

A `date` command appeared in Version 1 AT&T UNIX.

April 29, 2021 | Debian