Usage:
 hwclock [function] [option...]

Time clocks utility.

Functions:
 -r, --show                      display the RTC time
     --get                       display drift corrected RTC time
     --set                       set the RTC according to --date
 -s, --hctosys                   set the system time from the RTC
 -w, --systohc                   set the RTC from the system time
     --systz                     send timescale configurations to the kernel
 -a, --adjust                    adjust the RTC to account for systematic drift
     --param-get <param>         display the RTC parameter
     --param-set <param>=<value> set the RTC parameter
     --param-index <number>      parameter index (default 0)
     --vl-read                   read voltage low information
     --vl-clear                  clear voltage low information
     --predict                   predict the drifted RTC time according to --date

Options:
 -u, --utc                       the RTC timescale is UTC
 -l, --localtime                 the RTC timescale is Local
 -f, --rtc <file>                use an alternate file to /dev/rtc
     --directisa                 use the ISA bus instead of /dev/rtc access
     --date <time>               date/time input for --set and --predict
     --delay <sec>               delay used when set new RTC time
     --update-drift              update the RTC drift factor
     --noadjfile                 do not use /etc/adjtime
     --adjfile <file>            use an alternate file to /etc/adjtime
     --test                      dry run; implies --verbose
 -v, --verbose                   display more details

 -h, --help                      display this help
 -V, --version                   display version

Arguments:
 <param> is either a numeric RTC parameter value or one of these aliases:
   - features: supported features (0x0)
   - correction: time correction (0x1)
   - bsm: backup switch mode (0x2)
   See Kernel's include/uapi/linux/rtc.h for parameters and values.

 <param> and <value> accept hexadecimal values if prefixed with 0x, otherwise decimal.

For more details see hwclock(8).