1 .TH ADJTIME_CONFIG 5 "August 2018" "util-linux" "File Formats"
3 adjtime \- information about hardware clock setting and drift factor
9 contains descriptive information about the hardware mode clock setting and clock drift factor.
10 The file is read and write by hwclock; and read by programs like rtcwake to get RTC time mode.
12 The file is usually located in /etc, but tools like
16 allow to use alternative location by command line options if write access to
17 /etc is unwanted. The default clock mode is "UTC" if the file is missing.
19 The Hardware Clock is usually not very accurate. However, much of its inaccuracy is completely predictable - it gains
20 or loses the same amount of time every day. This is called systematic drift. The util hwclock keeps the file /etc/adjtime,
21 that keeps some historical information.
22 For more details see "\fBThe Adjust Function\fR" and "\fBThe Adjtime File\fR" sections from
27 The format of the adjtime file is, in ASCII.
30 Three numbers, separated by blanks:
33 the systematic drift rate in seconds per day (floating point decimal)
36 the resulting number of seconds since 1969 UTC of most recent adjustment or calibration (decimal integer)
38 .B "adjustment status"
39 zero (for compatibility with clock(8)) as a decimal integer.
43 .B "last calibration time"
44 The resulting number of seconds since 1969 UTC of most recent calibration.
45 Zero if there has been no calibration yet or it is known that any previous
46 calibration is moot (for example, because the Hardware Clock has been found,
47 since that calibration, not to contain a valid time). This is a decimal
53 Supported values are "UTC" or "LOCAL". Tells whether the Hardware Clock is set
54 to Coordinated Universal Time or local time. You can always override this
55 value with options on the hwclock command line.
63 This man page is part of the util-linux package and is available from
64 https://www.kernel.org/pub/linux/utils/util-linux/.