xlock(1)xlock(1)NAMExlock - locks the local X display until a password is entered
SYNOPSISxlock [ -display dsp ] [ -help ] [ -name resource-name ] [ -resources ]
[ -/+remote ]
[ -/+mono ] [ -/+nolock ] [ -/+allowroot ] [ -/+enablesaver ] [
-/+allowaccess ]
[ -/+echokeys ] [ -/+usefirst ] [ -/+v ] [ -delay usecs ] [
-batchcount num ]
[ -nice level ] [ -timeout seconds ] [ -saturation value ] [ -font
fontname ]
[ -bg color ] [ -fg color ] [ -mode modename ] [ -username
textstring ]
[ -password textstring ] [ -info textstring ] [ -validate
textstring ]
[ -invalid textstring ]
DESCRIPTIONxlock locks the X server till the user enters their password at the
keyboard. While xlock is running, all new server connections are
refused. The screen saver is disabled. The mouse cursor is turned
off. The screen is blanked and a changing pattern is put on the
screen. If a key or a mouse button is pressed then the user is
prompted for the password of the user who started xlock.
If the correct password is typed, then the screen is unlocked and the X
server is restored. When typing the password Control-U and Control-H
are active as kill and erase respectively. To return to the locked
screen, click in the small icon version of the changing pattern.
OPTIONS-display dsp
The display option sets the X11 display to lock. xlock locks all
available screens on a given server, and restricts you to locking
only a local server such as unix:0, localhost:0, or :0 unless you
set the -remote option.
-name resource-name
resource-name is used instead of XLock when looking for resources
to configure xlock.
-mode modename
As of this writing there are eight display modes supported (plus
one more for random selection of one of the eight).
hop Hop mode shows the "real plane fractals" from the September
1986 issue of Scientific American.
life Life mode shows Conway's game of life.
qix Qix mode shows the spinning lines similar to the old video game
by the same name.
image Image mode shows several logos randomly appearing on the
screen.
swarm Swarm mode shows a swarm of bees following a wasp.
rotor Rotor mode shows a swirling rotorlike thing.
pyro Pyro mode shows fireworks.
flame Flame mode shows wierd but cool fractals.
blank Blank mode shows nothing but a black screen.
random Random mode picks a random mode from all of the above except
blank mode.
-delay usecs
The delay option sets the speed at which a mode will operate. It
simply sets the number of microseconds to delay between batches of
animations. In blank mode, it is important to set this to some
small number of seconds, because the keyboard and mouse are only
checked after each delay, so you cannot set the delay too high,
but a delay of zero would needlessly consume cpu checking for
mouse and keyboard input in a tight loop, since blank mode has no
work to do.
-batchcount num
The batchcount option sets number of things to do per batch to num
. In hop mode this refers to the number of pixels rendered in the
same color. In life mode it is the number of generations to let
each species live. In qix mode it is the number of lines rendered
in the same color. In image mode it is the number of logos on
screen at once. In swarm mode it is the number of bees. In rotor
mode it is the number of rotor thingys which whirr... In pyro
mode it is the maximum number flying rockets at one time. In
flame mode it is the number of levels to recurse (larger = more
complex). In blank mode it means nothing.
-nice nicelevel
The nice option sets system nicelevel of the xlock process to
nicelevel .
-timeout seconds
The timeout option sets the number of seconds before the password
screen will time out.
-saturation value
The saturation option sets saturation of the color ramp used to
value . 0 is grayscale and 1 is very rich color. 0.4 is a nice
pastel.
-font fontname
The font option sets the font to be used on the prompt screen.
-fg color
The fg option sets the color of the text on the password screen to
color .
-bg color
The bg option sets the color of the background on the password
screen to color .
-username textstring
textstring is shown in front of user name, defaults to "Name: ".
-password textstring
textstring is the password prompt string, defaults to "Password:
".
-info textstring
textstring is an informational message to tell the user what to
do, defaults to "Enter password to unlock; select icon to lock.".
-validate textstring
textstring -validate message shown while validating the password,
defaults to "Validating login..."
-invalid textstring
textstring -invalid message shown when password is invalid,
defaults to "Invalid login."
-resources
The resources option prints the default resource file for xlock to
standard output.
-/+remote
The remote option tells xlock to not stop you from locking remote
X11 servers. This option should be used with care and is intended
mainly to lock X11 terminals which cannot run xlock locally. If
you lock someone else's workstation, they will have to know your
password to unlock it. Using +remote overrides any resource
derived values for remote and prevents xlock from being used to
lock other X11 servers. (Use `+' instead of `-' to override
resources for other options that can take the `+' modifier simi‐
larly.)
-/+mono
The mono option causes xlock to display monochrome, (black and
white) pixels rather than the default colored ones on color dis‐
plays.
+/-nolock
The nolock option causes xlock to only draw the patterns and not
lock the display. A keypress or a mouse click will terminate the
screen saver.
-/+allowroot
The allowroot option allows the root password to unlock the server
as well as the user who started xlock.
-/+enablesaver
By default xlock will disable the normal X server's screen saver
since it is in effect a replacement for it. Since it is possible
to set delay parameters long enough to cause phosphor burn on some
displays, this option will turn back on the default screensaver
which is very careful to keep most of the screen black.
-/+allowaccess
This option is required for servers which do not allow clients to
modify the host access control list. It is also useful if you
need to run x clients on a server which is locked for some rea‐
son... When allowaccess is true, the X11 server is left open for
clients to attach and thus lowers the inherent security of this
lockscreen. A side effect of using this option is that if xlock
is killed -KILL, the access control list is not lost.
-/+echokeys
The echokeys option causes xlock to echo '?' characters for each
key typed into the password prompt. Some consider this a security
risk, so the default is to not echo anything.
-/+usefirst
The usefirst option causes xlock to use the keystroke which got
you to the password screen as the first character in the password.
The default is to ignore the first key pressed.
-v Verbose mode, tells what options it is going to use.
**WARNING**
xlock can appear to hang if it is competing with a high-priority
process for the CPU. For example, if xlock is started after a process
with 'nice -20' (high priority), xlock will take considerable amount
of time to respond.
BUGS
"kill -KILLxlock " causes the server that was locked to be unusable,
since all hosts (including localhost) were removed from the access con‐
trol list to lock out new X clients, and since xlock couldn't catch
SIGKILL, it terminated before restoring the access control list. This
will leave the X server in a state where
"you can no longer connect to that server, and this operation cannot
be reversed unless you reset the server."
-From the X11R4 Xlib Documentation, Chapter 7.
SEE ALSO
Xlib Documentation.
AUTHOR
Patrick J. Naughton
COPYRIGHT
Copyright (c) 1988-91 by Patrick J. Naughton and Sun Microsystems, Inc.
Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee is hereby granted, pro‐
vided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in sup‐
porting documentation.
23 March 1992 xlock(1)
