XLOCK(1) MachTen Programmer’s Manual XLOCK(1)

NAME
xlock - Locks the local X display until a password is
entered.

SYNOPSIS
xlock [ -display dsp ] [ -help ] [ -nameresource-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 mode ] [ -username textstring ] [ -pass-
word textstring ] [ -info textstring ] [ -validate
textstring ] [ -invalid textstring ]

DESCRIPTION
xlock locks the X server till the user enters their pass-
word at the keyboard. While xlock is running, all new
server connections are refused. The screen saver is dis-
abled. 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 sup-
ported (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 sun 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 cosmic flame frac-
tals.

worm Worm mode shows wiggly worms...

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 "hopalong pixels", "qix
lines", "life generations", "image blits", and "swarm
motions". 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
sunlogos 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 worm mode it is the number of
worms. 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 pass-
word 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.

-/+mono
The mono option causes xlock to display monochrome,
(black and white) pixels rather than the default col-
ored ones on color displays

+/-nolock
The nolock option causes xlock to only draw the pat-
terns 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 reason... When
allowaccess is true, the X11 server is left open for
clients to attach and thus lowers the inherent secu-
rity 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 ’?’ charac-
ters 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.

BUGS
"kill -KILL xlock " causes the server that was locked to
be unusable, since all hosts (including localhost) were
removed from the access control list to lock out new X
clients, and since xlock couldn’t catch SIGKILL, it termi-
nated 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.

NCD terminals do not allow xlock to remove all the hosts
from the access control list. Therefore you will need to
use the "-remote" and "-noaccess" switches. If you happen
to run without "-noaccess" on an NCD terminal, xlock won’t
work and you will need to reboot the terminal, or simply
go into the SETUP menus, under ’Network Parameters’, and
turn off TCP/IP access control.