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Updated: Wednesday, February 10, 2021
 
 

xlock (1)

Name

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

Synopsis

xlock [ -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 ]

Description

xlock(1)                    General Commands Manual                   xlock(1)



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

SYNOPSIS
       xlock [ -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 ]


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.

       -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  -KILL  xlock " 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.


ATTRIBUTES
       See attributes(7) for descriptions of the following attributes:


       +---------------+------------------+
       |ATTRIBUTE TYPE | ATTRIBUTE VALUE  |
       +---------------+------------------+
       |Availability   | x11/xlock        |
       +---------------+------------------+
       |Stability      | Volatile         |
       +---------------+------------------+
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.




                               30 November 2010                       xlock(1)