XLOCK

Section: User Commands (1)
Updated: 28 Oct 1990
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NAME

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

SYNOPSIS

xlock [ -display dsp ] [ -/+remote ] [ -/+mono ] [ -/+nolock ] [ -/+allowroot ] [ -/+enablesaver ] [ -/+allowaccess ] [ -/+echokeys ] [ -/+v ] [ -delay usecs ] [ -batchcount num ] [ -nice level ] [ -timeout seconds ] [ -saturation value ] [ -font fontname ] [ -bg color ] [ -fg color ] [ -mode mode ] [ -name textstring ] [ -password textstring ] [ -info textstring ] [ -validate textstring ] [ -invalid textstring ]

DESCRIPTION

xlock 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.
-mode modename: As of this writing there are six display modes supported.
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.
blank: Blank mode shows nothing but a black screen.
-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 qix mode this refers to the number of lines rendered in the same color. In hop mode this refers to the number of pixels rendered in the same color. In image mode this refers to the number of sunlogos on screen at once. In swarm mode this refers to the number of bees. In life and 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 .
-name 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."
-/+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 colored ones on color displays
+/-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 simply a hack for the paranoid, who don't want to disable the access control list, but still want the local server to prompt for a password. This way 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.
-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 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.

AUTHOR

Patrick J. Naughton (naughton@wind.eng.sun.com)

MailStop 14-01
Windows and Graphics Group
Sun Microsystems, Inc.
Mountain View, CA 94043
415/336-1080

COPYRIGHT

Permission to use, copy, modify, and distribute this software and its documentation for any purpose and without fee is hereby granted, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation.

This document was created by man2html, using the manual pages.
Time: 21:45:36 GMT, February 02, 2023