# adjtime_config

## 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_
    


## 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/>. This page is
           part of the _util-linux_ (a random collection of Linux utilities)
           project. Information about the project can be found at 
           ⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩. If you have a
           bug report for this manual page, send it to
           util-linux@vger.kernel.org. This page was obtained from the
           project's upstream Git repository
           ⟨git://git.kernel.org/pub/scm/utils/util-linux/util-linux.git⟩ on
           2025-08-11. (At that time, the date of the most recent commit that
           was found in the repository was 2025-08-05.) If you discover any
           rendering problems in this HTML version of the page, or you
           believe there is a better or more up-to-date source for the page,
           or you have corrections or improvements to the information in this
           COLOPHON (which is _not_ part of the original manual page), send a
           mail to man-pages@man7.org
    
    util-linux 2.42-start-521-ec46  2025-01-16              _ADJTIME_CONFIG_(5)
    


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