adjtime_config

ADJTIME_CONFIG(5) File formats ADJTIME_CONFIG(5)

NAME

   adjtime_config - information about hardware clock setting and drift factor

SYNOPSIS

   /etc/adjtime

DESCRIPTION

   The file /etc/adjtime contains descriptive information about the hardware mode clock setting and clock drift factor. The file is read and write by hwclock(8); and read by programs
   like rtcwake to get RTC time mode.

   The file is usually located in /etc, but tools like hwclock(8) or rtcwake(8) can use alternative location by command line options if write access to /etc is unwanted. The default
   clock mode is "UTC" if the file is missing.

   The Hardware Clock is usually not very accurate. However, much of its inaccuracy is completely predictable - it gains or loses the same amount of time every day. This is called
   systematic drift. The util hwclock(8) keeps the file /etc/adjtime, that keeps some historical information. For more details see "The Adjust Function" and "The Adjtime File" sections
   from hwclock(8) man page.

   The adjtime file is formatted in ASCII.

First line

   Three numbers, separated by blanks:

   drift factor
       the systematic drift rate in seconds per day (floating point decimal)

   last adjust time
       the resulting number of seconds since 1969 UTC of most recent adjustment or calibration (decimal integer)

   adjustment status
       zero (for compatibility with clock(8)) as a floating point decimal

Second line

   last calibration time
       The resulting number of seconds since 1969 UTC of most recent calibration. Zero if there has been no calibration yet or it is known that any previous calibration is moot (for
       example, because the Hardware Clock has been found, since that calibration, not to contain a valid time). This is a decimal integer.

Third line

   clock mode
       Supported values are UTC or LOCAL. Tells whether the Hardware Clock is set to Coordinated Universal Time or local time. You can always override this value with options on the
       hwclock(8) command line.

FILES

   /etc/adjtime

SEE ALSO

   hwclock(8), rtcwake(8)

REPORTING BUGS

   For bug reports, use the issue tracker <https://github.com/util-linux/util-linux/issues>.

AVAILABILITY

   adjtime_config is part of the util-linux package which can be downloaded from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.

util-linux 2.41 2025-02-26 ADJTIME_CONFIG(5)