saveclock.8.in

.TH saveclock 8 "Jul 12, 2015"
.SH NAME
saveclock \- Restores/saves system clock from/to a file.
.SH SYNOPSIS
.B saveclock
.RB [ \-c\ \fIclock_file\fP ]
.RB [ \-i\ \fIsave_period_seconds\fP ]
.RB [ \-f ]
.RB [ \-e ]
.RB [ \-n ]
.RB [ \-d ]
.RB [ \-l\ \fIlock_file\fP ]
.RB [ \-p\ \fIpid_file\fP ]
.RB [ \-u\ \fIuser\fP ]
.RB [ \-g\ \fIgroup\fP ]
.RB [ \-j\ \fIjail_directory\fP ]
.RB [ \-h\ \fIworking_directory\fP ]
.RB { save | restore }
.SH DESCRIPTION
Saveclock is a system utility whose role is to restore and/or save the system
clock from/to a disk file. It can be used interactively (when one of the
\fBsave\fP or \fBrestore\fP action is specified) to execute a single action.
.P
However its main usage is as a daemon: in this mode, it restores the system
clock from the file upon start-up, periodically saves it back and finally saves
the system clock upon shut-down.
.P
This is particulary useful on systems without a working hardware RTC clock.
It avoids some problems that may be caused by a system believing it has
travelled in time back to 1970, by making sure the system clock is at least
as high as the last time it has been saved.
.P
In order to compensate time drifting introduced by this method, it is
recommended to use some "real" time source (NTP) synchronizing daemon in
complement to saveclock.
.SH OPTIONS
.TP
\fB-c\fR \fIclock_file\fR
Specifies the path of the file used as storage to save/restore the system clock.
Default: @STORAGEDIR@/lastclock.
.TP
\fB-i\fR \fIsave_period\fR
Defines the auto-save time interval. Setting it to zero disables timed
auto-save. Default: 60.
.TP
\fB-f\fR
Allow restoring the system clock even if the saved timestamp is before the
current system clock value.
.TP
\fB-e\fR
Log to standard error output.
.TP
\fB-n\fR
Do not log to system log. This is the default for non-daemon one-shot actions.
.TP
\fB-d\fR
Daemonize. Detach process from the current process group.
.TP
\fB-l\fR \fIlock_file\fR
Daemon lock file path. Unused if not daemonized. Default: @LOCKDIR@/saveclock.
.TP
\fB-p\fR \fIpid_file\fR
Daemon process id file. Unused if not daemonized. Default: @RUNDIR@/saveclock.
.TP
\fB-u\fR \fIuser\fR
Specifies the user name or id running the daemon. Default: current user.
.TP
\fB-g\fR \fIgroup\fR
Specifies the group name or id running the daemon. If not specified, it is
unchanged unless \fB-u\fR is given, in which case the group is set from the
user default group.
.TP
\fB-j\fR \fIjail_directory\fR
If specified, the file system root of the process is set to this path.
.TP
\fB-h\fR \fIworking_directory\fR
If specified, the process working directory is set to this path.
.SH FILES
@STORAGEDIR@/lastclock.
.SH AUTHORS
Patrick Monnerat <patrick@monnerat.net>.