Man page of SESSREG
Section: User Commands (1)
Updated: sessreg 1.0.4
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sessreg - manage utmp/wtmp entries for non-init clients
Sessreg is a simple program for managing utmp/wtmp
entries for xdm sessions.
System V has a better interface to utmp than BSD; it
dynamically allocates entries in the file, instead of writing them at fixed
positions indexed by position in
To manage BSD-style utmp files, sessreg has two strategies. In
conjunction with xdm, the -x option counts the number of lines in
and then adds to that the number of the line in the Xservers file which
specifies the display. The display name must be specified as the
"line-name" using the -l option. This sum is used as the "slot-number" in
the utmp file that this entry will be written at. In the more general case,
the -s option specifies the slot-number directly. If for some strange reason
your system uses a file other than
to manage init, the -t option can direct
sessreg to look elsewhere for a count of terminal sessions.
Conversely, System V managers will not ever need to use these options (-x,
-s and -t). To make the program easier to document and explain,
sessreg accepts the BSD-specific flags in the System V
environment and ignores them.
BSD and Linux also have a host-name field in the utmp file which doesn't
exist in System V. This option is also ignored by the System V version of
In Xstartup, place a call like:
sessreg -a -l $DISPLAY -x /etc/X11/xdm/Xservers $USER
and in Xreset:
sessreg -d -l $DISPLAY -x /etc/X11/xdm/Xservers $USER
- -w wtmp-file
This specifies an alternate wtmp file, instead of
The special name "none" disables writing records to the wtmp file.
- -u utmp-file
This specifies an alternate utmp file, instead of
The special name "none" disables writing records to the utmp file.
- -l line-name
This describes the "line" name of the entry. For terminal sessions,
this is the final pathname segment of the terminal device filename
(e.g. ttyd0). For X sessions, it should probably be the local display name
given to the users session (e.g. :0). If none is specified, the
terminal name will be determined with ttyname(3) and stripped of leading
- -h host-name
This is set for BSD hosts to indicate that the session was initiated from
a remote host. In typical xdm usage, this options is not used.
- -s slot-number
Each potential session has a unique slot number in BSD systems, most are
identified by the position of the line-name in the
This option overrides the default position determined with ttyslot(3).
This option is inappropriate for use with xdm, the -x option is more useful.
- -x Xservers-file
As X sessions are one-per-display, and each display is entered in this file,
this options sets the slot-number to be the number of lines in
the ttys-file plus the index into this file that the line-name
- -t ttys-file
This specifies an alternate file which the -x option will use to count
the number of terminal sessions on a host.
This session should be added to utmp/wtmp.
This session should be deleted from utmp/wtmp. One of -a/-d must
Keith Packard, MIT X Consortium
- SEE ALSO
This document was created by
using the manual pages.
Time: 03:41:17 GMT, September 24, 2010