NAME

xlock − locks the local X display until a password is entered

SYNOPSIS

xlock [ −display dsp ] [ −mode mode ] [ −time timeout ] [ −count n ] [ −font fontname ] [ −nice nicelevel ] [ −mono ] [ −saver ] [ −root ] [ −v ]

DESCRIPTION

xlock locks the X server until the user enters a 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 displayed on the screen.  The pattern changes after timeout seconds.  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 entered, then the screen is unlocked and the X server is restored.  When typing the password, characters are echoed to the screen as question marks (?), and Control-U and Control-H are active as kill and erase, respectively.  To return to the locked screen, click on the changing pattern icon. 

OPTIONS

−display  dsp
The display option sets the X11 display to lock.  xlock will not allow you to lock another server’s displays, thus, only unix:server.screen, localhost:server.screen, and :server.screen are allowed for dsp; where server is the X11 server socket to which to connect, and screen is the head on which to display the pattern. 

−mode  modename
Three display modes are 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. 

−time  timeout
The time option sets the number of seconds that each unique fractal will remain on the screen before being replaced by the next one to timeout. 

−count  n
The count option sets the speed at which a mode will operate.  The different modes interpret this value differently.  For hop and qix, this sets the number of pixels and lines, respectively, to draw in each color.  These patterns are calculated in batches of n objects, then sent to the server in a single color.  Faster machines, especially machines with floating point hardware can set this to a higher number and still have fast changing patterns.  The life mode, in contrast, interprets this number as the number of milliseconds to delay after each generation of the "critters."  A low number here makes the pattern change rapidly, where 1000 means wait a second between generations. 

−font  fontname
The font option sets the font to be used on the prompt screen. 

−nice  nicelevel
The nice option sets system nicelevel of the xlock process to nicelevel . 

−mono
The mono option causes xlock to display monochrome, (black and white) pixels rather than the default colored ones on color displays. 

−saver
The saver option causes xlock to draw only the patterns and not lock the display.  Pressing a key or clicking a mouse will terminate the screen saver. 

−root
The root option allows the root password to unlock the server as well as the user who started xlock.

−v Verbose mode, tells what options it is going to use. 

BUGS

"kill -KILL xlock " causes server to be unusable, since xlock has removed all hosts (including localhost) from the access control list to lock out all new X clients, and SIGKILL cannot be caught by any program, xlock will terminate 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 short of resetting the server."  -From the X11R2 Xlib Documentation page 140. 

SEE ALSO

X(1), Xlib Documentation. 

AUTHOR

 Patrick J. Naughton (naughton@sun.com)
 Window Systems Group
 Sun Microsystems, Inc.
 Mountain View, CA  94043
 415/336-1080

COPYRIGHT

Copyright (c) 1988-89 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, provided that the above copyright notice appear in all copies and that both the copyright notice and this permission notice appear in supporting documentation.

CONTRIBUTORS

  milliken@heron.bbn.comkarlton@wsl.dec.com
  dana@thumper.bellcore.comvesper@3d.dec.comflar@sun.com

September 02, 1992