


SCREEN(1)                                               SCREEN(1)


NNAAMMEE
       screen - screen manager with VT100/ANSI terminal emulation



SSYYNNOOPPSSIISS
       ssccrreeeenn [ --_o_p_t_i_o_n_s ] [ _c_m_d [ _a_r_g_s ] ]
       ssccrreeeenn --rr [ [_p_i_d_.]_t_t_y[_._h_o_s_t] ]



DDEESSCCRRIIPPTTIIOONN
       _S_c_r_e_e_n is a full-screen window manager that multiplexes  a
       physical  terminal  between  several  processes (typically
       interactive shells).  Each virtual terminal  provides  the
       functions  of  a DEC VT100 terminal and, in addition, sev-
       eral control functions from the ANSI X3.64 (ISO 6429)  and
       ISO  2022  standards  (e.g. insert/delete line and support
       for multiple character sets).  There is a scrollback  his-
       tory buffer for each virtual terminal and a copy-and-paste
       mechanism that allows moving text regions between windows.

       When  _s_c_r_e_e_n  is called, it creates a single window with a
       shell in it (or the specified command) and then  gets  out
       of  your  way  so that you can use the program as you nor-
       mally would.  Then, at any time, you can create new (full-
       screen)  windows  with  other  programs in them (including
       more shells), kill existing windows, view a list  of  win-
       dows,  turn output logging on and off, copy-and-paste text
       between  windows,  view  the  scrollback  history,  switch
       between  windows in whatever manner you wish, etc.  When a
       program terminates, _s_c_r_e_e_n (per default) kills the  window
       that  contained it.  If this window was in the foreground,
       the display switches to the previous window; if  none  are
       left, _s_c_r_e_e_n exits.

       Everything  you type is sent to the program running in the
       current window.  The only exception to  this  is  the  one
       keystroke that is used to initiate a command to the window
       manager.  By default, each command begins with a control-a
       (abbreviated  C-a  from  now  on),  and is followed by one
       other keystroke.  The command character and  all  the  key
       bindings  can be fully customized to be anything you like,
       though they are always two characters in length.

       The standard way to create a new window is  to  type  "C-a
       c".   This  creates  a  new  window  running  a  shell and
       switches to that window  immediately,  regardless  of  the
       state of the process running in the current window.  Simi-
       larly, you can create a new window with a  custom  command
       in it by first binding the command to a keystroke (in your
       .screenrc file or at the "C-a :" command  line)  and  then
       using  it just like the "C-a c" command.  In addition, new
       windows can be created by running a command like:



                            2 Aug 1993                          1





SCREEN(1)                                               SCREEN(1)


              screen emacs prog.c

       from a shell prompt within a  previously  created  window.
       This will not run another copy of _s_c_r_e_e_n, but will instead
       supply the command name and its arguments  to  the  window
       manager  (specified  in the $STY environment variable) who
       will use it to create the new window.  The  above  example
       would  start  the emacs editor (editing prog.c) and switch
       to its window.

       If "/etc/utmp"  is  writable  by  _s_c_r_e_e_n,  an  appropriate
       record  will  be written to this file for each window, and
       removed when the window is terminated.  This is useful for
       working with "talk", "script", "shutdown", "rsend", "sccs"
       and other similar programs  that  use  the  utmp  file  to
       determine who you are. As long as _s_c_r_e_e_n is active on your
       terminal, the terminal's own record is  removed  from  the
       utmp file. See also "C-a L".



GGEETTTTIINNGG SSTTAARRTTEEDD
       Before  you  begin  to use _s_c_r_e_e_n you'll need to make sure
       you have correctly selected your terminal  type,  just  as
       you  would  for  any other termcap/terminfo program.  (You
       can do this by using _t_s_e_t for example.)

       If you're impatient and want to get started without  doing
       a  lot more reading, you should remember this one command:
       "C-a ?".  Typing these two characters will display a  list
       of  the available _s_c_r_e_e_n commands and their bindings. Each
       keystroke is discussed in the section "DEFAULT  KEY  BIND-
       INGS".  The  manual section "CUSTOMIZATION" deals with the
       contents of your .screenrc.

       If possible, choose a version of your  terminal's  termcap
       that  has  automatic margins turned _o_f_f.  This will ensure
       an accurate and optimal update of the screen in  all  cir-
       cumstances.   The next best thing is an auto-margin termi-
       nal that allows the last position  on  the  screen  to  be
       updated  without  scrolling  the screen (such as a vt100).
       This also allows the entire screen to be updated.  Lastly,
       if  all you've got is a "true" auto-margin terminal _s_c_r_e_e_n
       will be content to use it, but updating  a  character  put
       into  the  last position on the screen may not be possible
       until the screen scrolls or the character is moved into  a
       safe position in some other way.  This delay can be short-
       ened by using a terminal with insert-character capability.

       If  your  terminal  is  of  the second type (firm-margined
       `am'), you will want to let _s_c_r_e_e_n know about this,  since
       a  normal  termcap  doesn't distinguish this type of auto-
       matic margins from a "true" `am' terminal.  You do this by
       specifying  the  `LP'  capability in your termcap (see the



                            2 Aug 1993                          2





SCREEN(1)                                               SCREEN(1)


       "termcap" .screenrc command), or by using the --LL  command-
       line  option.   _S_c_r_e_e_n needs this information to correctly
       update the screen. Note that a `xv' together with an  `am'
       flag effects like `LP'.

       If  you  are using a "true" auto-margin terminal (no `LP')
       at low baud rates, you may want to turn on a more  optimal
       output  mode  by  including  the flag `OP' in your termcap
       entry, or by specifying the --OO command-line  option.   The
       trade-off is that _s_c_r_e_e_n will no-longer accurately emulate
       the vt100's line-end quirks (e.g. the screen  will  scroll
       after  putting _o_n_e character in the last screen position).



CCOOMMMMAANNDD--LLIINNEE OOPPTTIIOONNSS
       Screen has the following command-line options:

       --aa   include _a_l_l capabilities (with some minor exceptions)
            in  each window's termcap, even if _s_c_r_e_e_n must redraw
            parts of the display in order to  implement  a  func-
            tion.

       --AA   Adapt  the  sizes  of  all windows to the size of the
            current  terminal.   By  default,  _s_c_r_e_e_n  tries   to
            restore  its  old  window  sizes  when  attaching  to
            resizeable terminals (those with "WS" in its descrip-
            tion, e.g. suncmd or some xterm).

       --cc _f_i_l_e
            override   the   default   configuration   file  from
            "$HOME/.screenrc" to _f_i_l_e.

       --dd|--DD [_p_i_d_._t_t_y_._h_o_s_t]
            does not start _s_c_r_e_e_n,  but  detaches  the  elsewhere
            running  _s_c_r_e_e_n  session.  It  has the same effect as
            typing "C-a d" from _s_c_r_e_e_n_'_s controlling terminal. --DD
            is  the  equivalent  to  the power detach key.  If no
            session can be detached, this option is ignored.  The
            combination "screen -D -r" can be used to `transport'
            the elsewhere running session to  this  terminal  and
            logout  there.   Note:  It is a good idea to have the
            status of your sessions checked by means  of  "screen
            -list".

       --ee _x_y
            specifies the command character to be _x and the char-
            acter generating a literal  command  character  to  _y
            (when   typed  after  the  command  character).   The
            default is "C-a" and `a', which can be  specified  as
            "-e^Aa".  See the "escape" .screenrc command for more
            details.





                            2 Aug 1993                          3





SCREEN(1)                                               SCREEN(1)


       --ff, --ffnn, and --ffaa
            turns flow-control on, off, or  "automatic  switching
            mode".   This  can  also be defined through the "def-
            flow" .screenrc command.

       --hh _n_u_m
            Specifies the history scrollback  buffer  to  be  _n_u_m
            lines high.

       --ii   will  cause the interrupt key (usually C-c) to inter-
            rupt the display immediately when flow-control is on.
            See the "defflow" .screenrc command for details.  The
            use of this option is discouraged.

       --ll and --llnn
            turns login mode on or off (for /etc/utmp  updating).
            This  can  also  be  defined  through  the "deflogin"
            .screenrc command.

       --llss and --lliisstt
            does  not  start  _s_c_r_e_e_n,  but  prints  a   list   of
            _p_i_d_._t_t_y_._h_o_s_t  strings  identifying  your  _s_c_r_e_e_n ses-
            sions.  Sessions marked  `detached'  can  be  resumed
            with "screen -r". Those marked `attached' are running
            and have a controlling terminal. Sessions  marked  as
            `dead'  should be thoroughly checked and removed. Ask
            your system administrator if you are not sure. Remove
            sessions with the --wwiippee option.

       --LL   tells _s_c_r_e_e_n your auto-margin terminal has a writable
            last-position on the screen.  This can also be set in
            your .screenrc by specifying `LP' in a "termcap" com-
            mand.

       --mm   causes _s_c_r_e_e_n to ignore the  $STY  environment  vari-
            able.  With  "screen -m" creation of a new session is
            enforced, regardless whether _s_c_r_e_e_n  is  called  from
            within another _s_c_r_e_e_n session or not.

       --OO   selects  a more optimal output mode for your terminal
            rather than true vt100 emulation (only affects  auto-
            margin terminals without `LP').  This can also be set
            in your .screenrc by specifying `OP' in  a  "termcap"
            command.

       --rr [_p_i_d_._t_t_y_._h_o_s_t]
            resumes  a detached _s_c_r_e_e_n session.  No other options
            (except "-d -r" or "-D -r") may be specified,  though
            an optional prefix of [_p_i_d_.]_t_t_y_._h_o_s_t may be needed to
            distinguish between  multiple  detached  _s_c_r_e_e_n  ses-
            sions.

       --RR   attempts  to resume the first detached _s_c_r_e_e_n session
            it finds.   If  successful,  all  other  command-line



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SCREEN(1)                                               SCREEN(1)


            options  are ignored.  If no detached session exists,
            starts a new session  using  the  specified  options,
            just  as  if --RR had not been specified. The option is
            set by default if screen is run as a login-shell.

       --ss   sets the default  shell  to  the  program  specified,
            instead  of  the  value  in  the environment variable
            $SHELL (or "/bin/sh" if not defined).  This can  also
            be defined through the "shell" .screenrc command.

       --SS _s_e_s_s_i_o_n_n_a_m_e
            When  creating a new session, this option can be used
            to specify a meaningful name for  the  session.  This
            name  identifies  the  session for "screen -list" and
            "screen  -r"  actions.  It  substitutes  the  default
            [_t_t_y_._h_o_s_t] suffix.

       --tt _n_a_m_e
            sets  the  title  (a.k.a.)  for  the default shell or
            specified  program.   See   also   the   "shelltitle"
            .screenrc command.

       --vv   Print version number.

       --wwiippee
            does  the same as "screen -ls", but removes destroyed
            sessions instead of marking them as `dead'.

       --xx   Attach to a not detached screen session. (Multi  dis-
            play mode).



DDEEFFAAUULLTT KKEEYY BBIINNDDIINNGGSS
       As mentioned, each _s_c_r_e_e_n command consists of a "C-a" fol-
       lowed by one other character.  For your  convenience,  all
       commands  that  are  bound  to lower-case letters are also
       bound to their control character  counterparts  (with  the
       exception of "C-a a"; see below), thus, "C-a c" as well as
       "C-a C-c" can be used to  create  a  window.  See  section
       "CUSTOMIZATION" for a description of the command.


       The following table shows the default key bindings:

       CC--aa ""
       CC--aa ""       (select)      Prompt for a window name or num-
                                 ber to switch to.

       CC--aa 00       (select 0)
        ......           ...
       CC--aa 99       (select 9)    Switch to window number 0 - 9.

       CC--aa CC--aa     (other)       Toggle to the  window  displayed



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SCREEN(1)                                               SCREEN(1)


                                 previously.    Note   that  this
                                 binding defaults to the  command
                                 character  typed  twice,  unless
                                 overridden; for instance, if you
                                 use   the  option  "--ee]]xx",  this
                                 function becomes "]]", not  "]C-
                                 a".

       CC--aa aa       (meta)        Send the command character (C-a)
                                 to window. See _e_s_c_a_p_e command.

       CC--aa AA       (title)       Allow the user to enter  a  name
                                 for the current window.

       CC--aa bb
       CC--aa CC--bb     (break)       Send a break to window.

       CC--aa BB       (pow_break)   Reopen  the  terminal  line  and
                                 send a break.

       CC--aa cc
       CC--aa CC--cc     (screen)      Create a new window with a shell
                                 and switch to that window.

       CC--aa CC       (clear)       Clear the screen.

       CC--aa dd
       CC--aa CC--dd     (detach)      Detach  _s_c_r_e_e_n  from this termi-
                                 nal.

       CC--aa DD DD     (pow_detach)  Detach and logout.

       CC--aa ff
       CC--aa CC--ff     (flow)        Toggle flow _o_n, _o_f_f or _a_u_t_o.

       CC--aa CC--gg     (vbell)       Toggles  _s_c_r_e_e_n_'_s  visual   bell
                                 mode.

       CC--aa hh       (hardcopy)    Write  a hardcopy of the current
                                 window to the file "hardcopy._n".

       CC--aa HH       (log)         Begins/ends  logging of the cur-
                                 rent window to the file "screen-
                                 log._n".

       CC--aa ii
       CC--aa CC--ii     (info)        Show info about this window.

       CC--aa kk
       CC--aa CC--kk     (kill)        Destroy current window.

       CC--aa ll
       CC--aa CC--ll     (redisplay)   Fully refresh current window.




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SCREEN(1)                                               SCREEN(1)


       CC--aa LL       (login)       Toggle  this windows login slot.
                                 Available only if _s_c_r_e_e_n is con-
                                 figured   to   update  the  utmp
                                 database.

       CC--aa mm
       CC--aa CC--mm     (lastmsg)     Repeat  the  last  message  dis-
                                 played in the message line.

       CC--aa MM       (monitor)     Toggles  monitoring  of the cur-
                                 rent window.

       CC--aa ssppaaccee
       CC--aa nn
       CC--aa CC--nn     (next)        Switch to the next window.

       CC--aa NN       (number)      Show the number (and  title)  of
                                 the current window.

       CC--aa bbaacckkssppaaccee
       CC--aa hh
       CC--aa pp
       CC--aa CC--pp     (prev)        Switch  to  the  previous window
                                 (opposite of CC--aa nn).

       CC--aa qq
       CC--aa CC--qq     (xon)         Send a control-q to the  current
                                 window.

       CC--aa rr
       CC--aa CC--rr     (wrap)        Toggle   the   current  window's
                                 line-wrap setting (turn the cur-
                                 rent  window's automatic margins
                                 on and off).

       CC--aa ss
       CC--aa CC--ss     (xoff)        Send a control-s to the  current
                                 window.

       CC--aa tt
       CC--aa CC--tt     (time)        Show system information.

       CC--aa vv
       CC--aa CC--vv     (version)     Display the version and compila-
                                 tion date.

       CC--aa ww
       CC--aa CC--ww     (windows)     Show a list of window.

       CC--aa WW       (width)       Toggle 80/132 columns.

       CC--aa xx
       CC--aa CC--xx     (lockscreen)  Lock this terminal.




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SCREEN(1)                                               SCREEN(1)


       CC--aa zz
       CC--aa CC--zz     (suspend)     Suspend
                                 _s_c_r_e_e_n._Y_o_u_rsystem_m_u_s_tsupport_B_S_D_-
                                 _s_t_y_l_ejob-control.

       CC--aa ZZ       (reset)       Reset the  virtual  terminal  to
                                 its "power-on" values.

       CC--aa ..       (dumptermcap) Write out a ".termcap" file.

       CC--aa ??       (help)        Show key bindings.

       CC--aa CC--\\     (quit)        Kill  all  windows and terminate
                                 _s_c_r_e_e_n.

       CC--aa ::       (colon)       Enter command line mode.

       CC--aa [[
       CC--aa CC--[[
       CC--aa eesscc     (copy)        Enter copy/scrollback mode.

       CC--aa ]]       (paste)       Write the contents of the  paste
                                 buffer to the stdin queue of the
                                 current window.

       CC--aa {{
       CC--aa }}       (history)     Copy and paste a previous  (com-
                                 mand) line.

       CC--aa >>       (writebuf)    Write pastebuffer to a file.

       CC--aa <<       (readbuf)     Reads  the  screen-exchange file
                                 into the pastebuffer.

       CC--aa ==       (removebuf)   Removes the file used by  CC--aa  <<
                                 and CC--aa >>.

       CC--aa ,,       (license)     Shows  where  screen comes from,
                                 where it went to and why you can
                                 use it.

       CC--aa __       (silence)     Start/stop  monitoring  the cur-
                                 rent window for inactivity.



CCUUSSTTOOMMIIZZAATTIIOONN
       The "socket directory" defaults either to $HOME/.screen or
       simply to /tmp/screens or preferably to /usr/local/screens
       chosen at compile-time. If  _s_c_r_e_e_n  is  installed  setuid-
       root, then the administrator should compile screen with an
       adequate (not NFS mounted) socket directory. If _s_c_r_e_e_n  is
       not running setuid-root, the user can specify any mode 777
       directory in the environment variable $SCREENDIR.



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SCREEN(1)                                               SCREEN(1)


       When _s_c_r_e_e_n is invoked, it  executes  initialization  com-
       mands   from   the   files  "/usr/local/etc/screenrc"  and
       ".screenrc" in the user's home directory.  These  are  the
       "programmer's defaults" that can be overridden in the fol-
       lowing ways: For the global screenrc file _s_c_r_e_e_n  searches
       for  the  environment variable $SYSSCREENRC (this override
       feature may be disabled at compile-time).  The  user  spe-
       cific  screenrc  file  is  searched  in  $ISCREENRC,  then
       $SCREENRC, then $HOME/.iscreenrc and finally  defaults  to
       $HOME/.screenrc.  The  command line option --cc takes prece-
       dence over the above user screenrc files.

       Commands in these files are  used  to  set  options,  bind
       functions  to  keys, and to automatically establish one or
       more windows at the  beginning  of  your  _s_c_r_e_e_n  session.
       Commands  are  listed one per line, with empty lines being
       ignored.  A command's arguments are separated by  tabs  or
       spaces,  and may be surrounded by single or double quotes.
       A `#' turns the rest of the line into a comment, except in
       quotes.    Unintelligible   lines  are  warned  about  and
       ignored.  Commands may contain references  to  environment
       variables.  The  syntax  is  the  shell-like  "$VAR  "  or
       "${VAR}". Note that this causes incompatibility with  pre-
       vious  _s_c_r_e_e_n versions, as now the '$'-character has to be
       protected with '\' if no variable  substitution  shall  be
       performed.  A  string  in  single-quotes is also protected
       from variable substitution.

       Customization can also be done  'on-line'.  To  enter  the
       command  mode  type  `C-a  :'. Note that commands starting
       with "def" change default values, while others change cur-
       rent settings.

       The following commands are available:

       aaccllaadddd _u_s_e_r_n_a_m_e

       Enable  a user to (fully) access this screen session. Nec-
       essary to allow other users to attach to this _s_c_r_e_e_n  ses-
       sion. Same as `aclchg _u_s_e_r_n_a_m_e +rwx "#?"'. Multi user mode
       only.

       aaccllcchhgg _u_s_e_r_n_a_m_e _p_e_r_m_b_i_t_s _l_i_s_t

       Change a users permissions.  Permission  bits  are  repre-
       sented as `r', `w' and `x'.  Prefixing `+' grants the per-
       mission, `-' removes it. The third parameter  is  a  komma
       seperated list of commands or windows (specified either by
       number or title). The special list `#' refers to all  win-
       dows, `?' to all commands.  A Command can be executed when
       the user has the `x' bit for it.  The user can type  input
       to a window, when he has its `w' bit set and no other user
       obtains a writelock for this window. Other bits  are  cur-
       rently ignored.  Multi user mode only.



                            2 Aug 1993                          9





SCREEN(1)                                               SCREEN(1)


       aaccllddeell _u_s_e_r_n_a_m_e

       Remove  a  user  from screens access control list. If cur-
       rently attached, all the users displays are detached  from
       the  session.  He  cannot  attach  again.  Multi user mode
       only.

       aaccttiivviittyy _m_e_s_s_a_g_e

       When any activity occurs in a background  window  that  is
       being  monitored,  _s_c_r_e_e_n  displays  a notification in the
       message line.  The notification message can be  re-defined
       by  means  of  the "activity" command.  Each occurrence of
       `%' in _m_e_s_s_a_g_e is replaced by the number of the window  in
       which activity has occurred, and each occurrence of `~' is
       replaced by the definition for bell in your termcap  (usu-
       ally an audible bell).  The default message is

                   'Activity in window %'

       Note  that  monitoring  is off for all windows by default,
       but can be altered by use of the  "monitor"  command  (C-a
       M).

       aallllppaarrttiiaall oonn|ooffff

       If set to on, only the current cursor line is refreshed on
       window change.  This affects all windows and is useful for
       slow  terminal lines. The previous setting of full/partial
       refresh for each window is restored with "allpartial off".

       aatt [_i_d_e_n_t_i_f_i_e_r][##|**|%%] _c_o_m_m_a_n_d [_a_r_g_s ... ]

       Execute  a  command  at other displays or windows as if it
       had been entered there.  "At"  changes  the  context  (the
       `current window' or `current display' setting) of the com-
       mand. If the first parameter describes a  non-unique  con-
       text,  the command will be executed multiple times. If the
       first parameter is of the form `_i_d_e_n_t_i_f_i_e_r*' then  identi-
       fier  is  matched against user names.  The command is exe-
       cuted once for each display of the  selected  user(s).  If
       the  first  parameter is of the form `_i_d_e_n_t_i_f_i_e_r%' identi-
       fier is matched against displays. Displays are named after
       the ttys they attach. The prefix `/dev/' or `/dev/tty' may
       be ommited from the identifier.  If _i_d_e_n_t_i_f_i_e_r has  a  `#'
       or  nothing  appended it is matched against window numbers
       and titles. Omitting an identifier in front  of  the  `#',
       `*'  or  `%'-character selects all users, displays or win-
       dows because a prefix-match is performed. Note that on the
       affected  display(s)  a  short  message will describe what
       happened.






                            2 Aug 1993                         10





SCREEN(1)                                               SCREEN(1)


       aauuttooddeettaacchh oonn|ooffff

       Sets whether _s_c_r_e_e_n will automatically detach upon hangup,
       which  saves  all  your  running  programs  until they are
       resumed with a ssccrreeeenn --rr  command.   When  turned  off,  a
       hangup  signal will terminate _s_c_r_e_e_n and all the processes
       it contains. Autodetach is on by default.

       aauuttoonnuukkee oonn|ooffff

       Sets whether a clear screen sequence should nuke  all  the
       output that has not been written to the terminal. See also
       "obuflimit".

       bbeellll _m_e_s_s_a_g_e

       When a bell character is  sent  to  a  background  window,
       _s_c_r_e_e_n  displays  a notification in the message line.  The
       notification message can be re-defined  by  means  of  the
       "bell"  command.   Each  occurrence  of  `%' in _m_e_s_s_a_g_e is
       replaced by the number of the window to which a  bell  has
       been  sent,  and each occurrence of `~' is replaced by the
       definition for bell in your termcap  (usually  an  audible
       bell).  The default message is

                   'Bell in window %'

       An  empty message can be supplied to the "bell" command to
       suppress output of a message line (bell "").

       bbiinndd _k_e_y [_c_o_m_m_a_n_d [_a_r_g_s]]

       Bind a command to a key.  By default, most of the commands
       provided  by _s_c_r_e_e_n are bound to one or more keys as indi-
       cated in the "DEFAULT KEY BINDINGS" section, e.g. the com-
       mand  to  create  a  new window is bound to "C-c" and "c".
       The "bind" command can be used to redefine the  key  bind-
       ings  and  to  define  new  bindings.  The _k_e_y argument is
       either a single character, a two-character sequence of the
       form  "^x"  (meaning  "C-x"),  a  backslash followed by an
       octal number (specifying the ASCII code of the character),
       or  a  backslash  followed  by a second character, such as
       "\^" or "\\".  The argument can also  be  quoted,  if  you
       like.   If  no  further  argument is given, any previously
       established binding for this key is removed.  The  _c_o_m_m_a_n_d
       argument can be any command listed in this section.

       Some examples:

                   bind ' ' windows
                   bind ^f screen telnet foobar
                   bind \033 screen -ln -t root -h 1000 9 su

       would  bind  the  space key to the command that displays a



                            2 Aug 1993                         11





SCREEN(1)                                               SCREEN(1)


       list of windows (so that the command  usually  invoked  by
       "C-a  C-w"  would  also be available as "C-a space"), bind
       "C-f" to the command "create a window with a  TELNET  con-
       nection  to foobar", and bind "escape" to the command that
       creates an non-login window with a.k.a. "root" in slot #9,
       with  a  super-user  shell and a scrollback buffer of 1000
       lines.

       bbrreeaakk [_d_u_r_a_t_i_o_n]

       Send a break signal for _d_u_r_a_t_i_o_n*0.25 seconds to this win-
       dow.  Most useful if a character device is attached to the
       window rather than a shell process.

       bbuuffffeerrffiillee [_e_x_c_h_a_n_g_e_-_f_i_l_e]

       Change the filename used for reading and writing with  the
       copybuffer.   If the optional argument to the "bufferfile"
       command is omitted,  the  default  setting  ("/tmp/screen-
       exchange")  is  reactivated.   The  following example will
       paste the system's password file into the screen window:

                   C-a : bufferfile /etc/passwd
                   C-a < C-a ]
                   C-a : bufferfile

       cchhddiirr [_d_i_r_e_c_t_o_r_y]

       Change the _c_u_r_r_e_n_t _d_i_r_e_c_t_o_r_y of _s_c_r_e_e_n  to  the  specified
       directory  or, if called without an argument, to your home
       directory (the value of the environment  variable  $HOME).
       All windows that are created by means of the "screen" com-
       mand from within ".screenrc" or by means of "C-a :  screen
       ..."  or  "C-a  c"  use  this  as their default directory.
       Without a chdir command, this would be the directory  from
       which  _s_c_r_e_e_n  was  invoked.   Hardcopy  and log files are
       always written to the _w_i_n_d_o_w_'_s default directory, _n_o_t  the
       current  directory  of  the process running in the window.
       You can use this command multiple times in your  .screenrc
       to start various windows in different default directories,
       but the last chdir value will affect all the  windows  you
       create interactively.

       cclleeaarr

       Clears  the  current  window  and  saves  its image to the
       scrollback buffer.

       ccoolloonn

       Allows you to enter ".screenrc" command lines. Useful  for
       on-the-fly  modification  of key bindings, specific window
       creation and changing settings. Note that the  "set"  key-
       word no longer exists! Usually commands affect the current



                            2 Aug 1993                         12





SCREEN(1)                                               SCREEN(1)


       window rather than default settings  for  future  windows.
       Change defaults with commands starting with 'def...'.

       If  you  consider this as the `Ex command mode' of _s_c_r_e_e_n,
       you may regard "C-a esc" (copy mode) as  its  `Vi  command
       mode'.

       ccoonnssoollee [oonn|ooffff]

       Grabs  or ungrabs the machines console output to a window.

       ccooppyy

       Enter copy/scrollback mode. This allows you to  copy  text
       from  the  current  window  and its history into the paste
       buffer. In this mode a vi-like  `full  screen  editor'  is
       active:
       _M_o_v_e_m_e_n_t _k_e_y_s:
         hh,  jj,  kk,  ll  move the cursor line by line or column by
           column.
         00, ^^ and $$ move to the leftmost column, to the first  or
           last non-whitespace character on the line.
         HH, MM and LL move the cursor to the leftmost column of the
           top, center or bottom line of the window.
         ++ and -- positions one line up and down.
         GG moves to the specified absolute line (default: end  of
           buffer).
         || moves to the specified absolute column.
         ww, bb, ee move the cursor word by word.
         CC--uu  and CC--dd scroll the display up/down by the specified
           amount of lines while preserving the cursor  position.
           (Default: half screen-full).
         CC--bb and CC--ff scroll the display up/down a full screen.
         gg moves to the beginning of the buffer.
         %% jumps to the specified percentage of the buffer.

       _N_o_t_e:
           Emacs  style  movement  keys  can  be  customized by a
           .screenrc command.  (E.g.  markkeys  "h=^B:l=^F:$=^E")
           There  is  no  simple  method  for  a full emacs-style
           keymap, as this involves multi-character codes.

       _M_a_r_k_i_n_g:
           The copy range is specified by setting two marks.  The
           text between these marks will be highlighted. Press
         ssppaaccee to set the first or second mark respectively.
         YY  and  yy  used  to  mark one whole line or to mark from
           start of line.
         WW marks exactly one word.
       _R_e_p_e_a_t _c_o_u_n_t:
           Any of these commands can be prefixed  with  a  repeat
           count number by pressing digits
         00..99 which is taken as a repeat count.
           Example: "C-a C-[ H 10 j 5 Y" will copy lines 11 to 15



                            2 Aug 1993                         13





SCREEN(1)                                               SCREEN(1)


           into the pastebuffer.
       _S_e_a_r_c_h_i_n_g:
         // _V_i-like search forward.
         ?? _V_i-like search backward.
         CC--aa ss _E_m_a_c_s style incremental search forward.
         CC--rr _E_m_a_c_s style reverse i-search.
       _S_p_e_c_i_a_l_s:
           There are however some keys that act differently  than
           in  _v_i.   _V_i  does  not  allow one to yank rectangular
           blocks of text, but _s_c_r_e_e_n does. Press
         cc or CC to set the left or right margin respectively.  If
           no  repeat count is given, both default to the current
           cursor position.
           Example: Try this on a rather full text screen: "C-a [
           M 20 l SPACE c 10 l 5 j C SPACE".

           This moves one to the middle line of the screen, moves
           in 20 columns left, marks the beginning of  the  copy-
           buffer,  sets  the  left column, moves 5 columns down,
           sets the right column, and then marks the end  of  the
           copybuffer. Now try:
           "C-a [ M 20 l SPACE 10 l 5 j SPACE"

           and  notice  the  difference  in  the  amount  of text
           copied.
         JJ joins lines. It toggles between 3 modes:  lines  sepa-
           rated  by a newline character (012), lines glued seam-
           less, lines separated by  a  single  whitespace.  Note
           that you can prepend the newline character with a car-
           riage return character, by issuing a "crlf on".
         vv is for all the _v_i users with ":set numbers" - it  tog-
           gles the left margin between column 9 and 1. Press
         aa  before  the final space key to toggle in append mode.
           Thus the contents of the pastebuffer will not be over-
           written, but is appended to.
         AA toggles in append mode and sets a (second) mark.
         >>  sets the (second) mark and writes the contents of the
           copybuffer to the screen-exchange  file  (/tmp/screen-
           exchange per default) once copy-mode is finished.
           This  example  demonstrates  how  to  dump  the  whole
           scrollback buffer to that file: "C-A [ g SPACE G $ >".
         CC--gg gives information about the current line and column.
         @@ does nothing. Does not even exit copy mode.

       ccooppyy__rreegg [_k_e_y]

       Store the current copybuffer contents in a register refer-
       enced by _k_e_y.  If the name is omitted you will be prompted
       to press the key.

       ccrrllff oonn|ooffff

       This affects the copying of text regions with the `C-a  ['
       command.  If it is set to `on', lines will be separated by



                            2 Aug 1993                         14





SCREEN(1)                                               SCREEN(1)


       the  two  character  sequence  `CR'  -  `LF'.    Otherwise
       (default) only `LF' is used.

       ddeebbuugg oonn|ooffff

       Turns runtime debugging on or off. If _s_c_r_e_e_n has been com-
       piled with  option  -DDEBUG  debugging  available  and  is
       turned on per default. Note that this command only affects
       debugging output from the main "SCREEN" process.

       ddeeffaauuttoonnuukkee oonn|ooffff

       Same as the aauuttoonnuukkee command except that the default  set-
       ting  for  new  displays  is  changed.  Initial setting is
       `off'.  Note that you can use the  special  'AN'  terminal
       capability  if you want to have a dependency on the termi-
       nal type.

       ddeeffffllooww oonn|ooffff|aauuttoo [iinntteerrrruupptt]

       Same as the ffllooww command except that the  default  setting
       for  new  windows  is  changed. Initial setting is `auto'.
       Specifying "defflow auto interrupt" is  the  same  as  the
       command-line options --ffaa and --ii.

       ddeeffllooggiinn oonn|ooffff

       Same  as the llooggiinn command except that the default setting
       for new windows is changed. This is initialised with  `on'
       as distributed (see config.h.in).

       ddeeffmmooddee _m_o_d_e

       The  mode  of  each  newly  allocated pseudo-tty is set to
       _m_o_d_e.  _M_o_d_e is an octal number.  When no "defmode" command
       is given, mode 0622 is used.

       ddeeffmmoonniittoorr oonn|ooffff

       Same  as  the mmoonniittoorr command except that the default set-
       ting for new windows is changed. Initial setting is `off'.

       ddeeffoobbuufflliimmiitt _l_i_m_i_t

       Same as the oobbuufflliimmiitt command except that the default set-
       ting for new displays is changed. Initial setting  is  256
       bytes.   Note  that  you can use the special 'OL' terminal
       capability if you want to have a dependency on the  termi-
       nal type.

       ddeeffssccrroollllbbaacckk _n_u_m

       Same  as  the  ssccrroollllbbaacckk  command except that the default
       setting for new windows is  changed.  Initial  setting  is



                            2 Aug 1993                         15





SCREEN(1)                                               SCREEN(1)


       100.

       ddeeffwwrraapp oonn|ooffff

       Same  as  the wwrraapp command except that the default setting
       for new windows is changed. Initially line-wrap is on  and
       can  be  toggled  with  the "wrap" command ("C-a r") or by
       means of "C-a : wrap on|off".

       ddeettaacchh

       Detach the _s_c_r_e_e_n session (disconnect it from the terminal
       and  put it into the background).  This returns you to the
       shell where you invoked _s_c_r_e_e_n.  A detached _s_c_r_e_e_n can  be
       resumed  by  invoking _s_c_r_e_e_n with the --rr option. (See also
       section "COMMAND-LINE OPTIONS".)

       dduummpptteerrmmccaapp

       Write the termcap entry for the virtual terminal optimized
       for  the currently active window to the file ".termcap" in
       the user's "$HOME/.screen" directory (or  wherever  _s_c_r_e_e_n
       stores  its sockets. See the "FILES" section below).  This
       termcap entry is identical to the value of the environment
       variable  $TERMCAP  that is set up by _s_c_r_e_e_n for each win-
       dow. For terminfo based systems you will  need  to  run  a
       converter  like  _c_a_p_t_o_i_n_f_o and then compile the entry with
       _t_i_c.

       eecchhoo [--nn] _m_e_s_s_a_g_e

       The echo command may be used to annoy _s_c_r_e_e_n users with  a
       'message  of  the  day'.  Typically  installed in a global
       /local/etc/screenrc. See also "sleep".  Echo is also  use-
       ful for online checking of environment variables.

       eessccaappee _x_y

       Set  the command character to _x and the character generat-
       ing a literal command character to _y (just like in the  -e
       option).   Each  argument  is either a single character, a
       two-character sequence of the form "^x" (meaning "C-x"), a
       backslash  followed  by  an  octal  number (specifying the
       ASCII code of the character), or a backslash followed by a
       second  character,  such  as "\^" or "\\".  The default is
       "^Aa".

       eexxeecc [[_f_d_p_a_t] _n_e_w_c_o_m_m_a_n_d [_a_r_g_s _._._.]]

       Run a subprocess (newcommand) in the current  window.  The
       flow  of data between newcommands stdin/stdout/stderr, the
       process already running (shell) and screen itself (window)
       is  controlled  by the filedescriptor pattern fdpat.  This
       pattern  is   basically   a   three   character   sequence



                            2 Aug 1993                         16





SCREEN(1)                                               SCREEN(1)


       representing stdin, stdout and stderr of newcommand. A dot
       (.) connects the file descriptor to screen. An exclamation
       mark (!) causes the file descriptor to be connected to the
       already running process. A colon (:) combines both.   User
       input will go to newcommand unless newcommand requests the
       old process' output (fdpats first character is `!' or `:')
       or a pipe (|) is added to the end of fdpat.
       Invoking `exec' without arguments shows name and arguments
       of the currently running subprocess in this window.
       When a subprocess  is  running  the  `kill'  command  will
       affect it instead of the windows process.
       Refer  to the postscript file `fdpat.ips' for illustration
       of all 21 possible combinations. Each  drawing  shows  the
       numbers  210  representing  the  three file descriptors of
       newcommand. The box marked `W' is usual pty that  has  the
       old  process (shell) on its slave side. The box marked `P'
       is the secondary pty that now has  screen  at  its  master
       side.

       Abbreviations:
       Whitespace  between the word `exec' and fdpat and the com-
       mand can be omitted. Trailing dots and a fdpat  consisting
       only  of  dots  can be omitted. A simple `|' is synonymous
       for the pattern `!..|'; the word exec can be ommitted here
       and can always be replaced by `!'.

       Examples:

              exec ... /bin/sh
              exec /bin/sh
              !/bin/sh

       Creates  another shell in the same window, while the orig-
       nal shell is still running. Output of both shells is  dis-
       played and user input is sent to the new /bin/sh.

              exec !.. stty 19200
              exec ! stty 19200
              !!stty 19200

       Set  the  speed  of  the windows tty. If your stty command
       operates on stdout, then add another `!'.

              exec !..| less
              |less

       This adds a pager to the window output. The special  char-
       acter  `|'  is  needed  to  give the user control over the
       pager although it gets its input from  the  original  pro-
       cess.

              !:sed -n s/.*Error.*/\007/p

       Sends window output to both, the user and the sed command.



                            2 Aug 1993                         17





SCREEN(1)                                               SCREEN(1)


       The sed inserts an additional bell character (oct. 007) to
       the  window  output seen by screen.  This will cause "Bell
       in window x" messages, whenever the string "Error" appears
       in the window.

       ffllooww [oonn|ooffff|aauuttoo]

       Sets  the  flow-control  mode  for  this  window.  Without
       parameters it cycles  the  current  window's  flow-control
       setting  from  "automatic" to "on" to "off".  See the dis-
       cussion on "FLOW-CONTROL" later on in  this  document  for
       full  details  and note, that this is subject to change in
       future releases.  Default is set by `defflow'.

       hhaarrddccooppyy

       Writes out the currently displayed image to a  file  _h_a_r_d_-
       _c_o_p_y_._n  in  the window's default directory, where _n is the
       number of the current  window.   This  either  appends  or
       overwrites the file if it exists. See below.

       hhaarrddccooppyy__aappppeenndd oonn|ooffff

       If  set  to  "on",  _s_c_r_e_e_n will append to the "hardcopy.n"
       files created by the  command  "C-a  h",  otherwise  these
       files are overwritten each time.  Default is `off'.

       hhaarrddccooppyyddiirr _d_i_r_e_c_t_o_r_y

       Defines  a  directory where hardcopy files will be placed.
       If unset hardcopys are dumped in screens  current  working
       directory.

       hhaarrddssttaattuuss [oonn|ooffff]

       Toggles the use of the terminal's hardware status line. If
       "on", _s_c_r_e_e_n will use this facility to  display  one  line
       messages.   Otherwise  these  messages  are  overlayed  in
       reverse video mode at the  display  line.  Note  that  the
       hardstatus   feature   can  only  be  used  if  the  term-
       cap/terminfo capabilities "hs", "ts", "fs"  and  "ds"  are
       set properly. Default is `on' whenever the "hs" capability
       is present.

       hheeiigghhtt [_l_i_n_e_s]

       Set the display height to a  specified  number  of  lines.
       When  no  argument  is  given it toggles between 24 and 42
       lines display.

       hheellpp

       Not really a online help, but displays a help screen show-
       ing  you  all  the key bindings.  The first pages list all



                            2 Aug 1993                         18





SCREEN(1)                                               SCREEN(1)


       the internal commands followed by their current  bindings.
       Subsequent  pages  will  display  the custom commands, one
       command per key.  Press space  when  you're  done  reading
       each  page, or return to exit early.  All other characters
       are ignored, except for the command character, which  will
       allow you to execute commands even when the help screen is
       still visible.  See also "DEFAULT KEY BINDINGS" section.

       hhiissttoorryy

       Usually users work with a shell that allows easy access to
       previous  commands.   For example csh has the command "!!"
       to repeat the last command executed.  _S_c_r_e_e_n allows you to
       have  a  primitive  way  of  re-calling  "the command that
       started ...": You just type the first letter of that  com-
       mand, then hit `C-a {' and _s_c_r_e_e_n tries to find a previous
       line that matches with the `prompt character' to the  left
       of  the  cursor.  This  line  is pasted into this window's
       input queue.  Thus you have a crude command history  (made
       up by the visible window and its scrollback buffer).

       iinnffoo

       Uses  the  message  line to display some information about
       the current window: the cursor position in the form "(col-
       umn,row)"  starting  with  "(1,1)", the terminal width and
       height plus the size of the scrollback  buffer  in  lines,
       like in "(80,24)+50", various flag settings (flow-control,
       insert mode, origin mode,  wrap  mode,  application-keypad
       mode,  output logging, activity monitoring and redraw (`+'
       indicates enabled, `-' not)), the currently active charac-
       ter  set  (_G_0,  _G_1, _G_2, or _G_3), and in square brackets the
       terminal character sets that are currently  designated  as
       _G_0 through _G_3.  For system information use the "time" com-
       mand.

       iinnss__rreegg [_k_e_y]

       Paste contents of register _k_e_y in  current  windows  input
       stream. See also the "copy_reg" and "register" commands.

       kkiillll

       Kill current window.
       If  there  is an `exec' command running then it is killed.
       Otherwise  the  process  (shell)  running  in  the  window
       receives  a  HANGUP  condition,  the  window  structure is
       removed and screen switches to  the  previously  displayed
       window.   When the last window is destroyed, _s_c_r_e_e_n exits.
       Note: _E_m_a_c_s users should keep this command in  mind,  when
       killing a line.  It is recommended not to use "C-a" as the
       _s_c_r_e_e_n escape key or to rebind kill to "C-a K".





                            2 Aug 1993                         19





SCREEN(1)                                               SCREEN(1)


       llaassttmmssgg

       Redisplay the last contents of  the  message/status  line.
       Useful  if  you're  typing when a message appears, because
       the message goes away when you press a  key  (unless  your
       terminal  has  a hardware status line).  Refer to the com-
       mands "msgwait" and "msgminwait" for fine tuning.

       lliicceennssee

       Display the disclaimer page. This is done whenever  _s_c_r_e_e_n
       is  started without options, which should be often enough.
       See also the "startup_message" command.

       lloocckkssccrreeeenn

       Lock   this   display.    Call   a   screenlock    program
       (/local/bin/lck  or /usr/bin/lock or a builtin if no other
       is available). Screen does not  accept  any  command  keys
       until  this program terminates. Meanwhile processes in the
       windows may continue, as the windows are in the `detached'
       state.  The  screenlock program may be changed through the
       environment variable $LOCKPRG (which must be  set  in  the
       shell  from  which _s_c_r_e_e_n is started) and is executed with
       the user's uid and gid.

       lloogg [oonn|ooffff]

       Start/stop writing output of the current window to a  file
       "screenlog._n"  in  the window's default directory, where _n
       is the number of the current window. If  no  parameter  is
       given, the state of logging is toggled. The session log is
       appended to the  previous  contents  of  the  file  if  it
       already  exists.  The current contents and the contents of
       the scrollback history are not  included  in  the  session
       log.  Default is `off'.

       llooggddiirr _d_i_r_e_c_t_o_r_y

       Defines  a  directory  where  logfiles  will be placed. If
       unset logfiles are  written  in  screens  current  working
       directory.

       llooggiinn [oonn|ooffff]

       Adds  or  removes  the entry in the utmp database file for
       the current  window.   This  controls  if  the  window  is
       `logged  in'.  When no parameter is given, the login state
       of the window is toggled.  Additionally to that toggle, it
       is  convenient having a `log in' and a `log out' key. E.g.
       `bind I login on' and `bind O login off'  will  map  these
       keys  to be C-a I and C-a O.  The default setting (in con-
       fig.h.in) should be "on" for  a  _s_c_r_e_e_n  that  runs  under
       suid-root.   Use  the  "deflogin"  command  to  change the



                            2 Aug 1993                         20





SCREEN(1)                                               SCREEN(1)


       default login state for new  windows.  Both  commands  are
       only  present when _s_c_r_e_e_n has been compiled with utmp sup-
       port.

       mmaarrkkkkeeyyss _s_t_r_i_n_g

       This  is  a  method  of  changing  the  keymap  used   for
       copy/history   mode.   The  string  is  made  up  of  _o_l_d_-
       _c_h_a_r=_n_e_w_c_h_a_r pairs which are separated  by  `:'.  Example:
       The  string "B=^B:F=^F" will change the keys `C-b' and `C-
       f' to the vi style binding  (scroll  up/down  fill  page).
       This  happens  to  be the default binding for `B' and `F'.
       The command "markkeys h=^B:l=^F:$=^E" would set  the  mode
       for an emacs-style binding.

       mmeettaa

       Insert the command character (C-a) in the current window's
       input stream.

       mmoonniittoorr [oonn|ooffff]

       Toggles activity monitoring of windows.   When  monitoring
       is  turned  on and an affected window is switched into the
       background, you will  receive  the  activity  notification
       message in the status line at the first sign of output and
       the window will also be marked with an `@' in the  window-
       status  display.  Monitoring is initially off for all win-
       dows.

       mmssggmmiinnwwaaiitt _s_e_c

       Defines the time _s_c_r_e_e_n delays a new message when one mes-
       sage is currently displayed.  The default is 1 second.

       mmssggwwaaiitt _s_e_c

       Defines  the  time a message is displayed if _s_c_r_e_e_n is not
       disturbed by other activity. The default is 5 seconds.

       mmuullttiiuusseerr oonn|ooffff

       Switch between singleuser  and  multiuser  mode.  Standard
       screen operation is singleuser. In multiuser mode the com-
       mands `acladd' and `acldel' can be  used  to  enable  (and
       disable) other users to access this screen.

       nneetthhaacckk oonn|ooffff

       Changes  the  kind of error messages used by _s_c_r_e_e_n.  When
       you are familiar with the game "nethack",  you  may  enjoy
       the nethack-style messages which will often blur the facts
       a little, but are much funnier to read.  Anyway,  standard
       messages often tend to be unclear as well.



                            2 Aug 1993                         21





SCREEN(1)                                               SCREEN(1)


       This  option is only available if screen was compiled with
       the NETHACK flag defined.  The  default  setting  is  then
       determined  by  the  presence  of the environment variable
       $NETHACKOPTIONS.

       nneexxtt

       Switch to the next  window.   This  command  can  be  used
       repeatedly to cycle through the list of windows.

       nnuummbbeerr [_n]

       Change  the  current windows number. If the given number _n
       is already used by another window, both  windows  exchange
       their  numbers.  If  no argument is specified, the current
       window number (and title) is shown.

       oobbuufflliimmiitt [_l_i_m_i_t]

       If the output buffer contains more bytes than  the  speci-
       fied  limit,  no  more data will be read from the windows.
       The default value is 256. If you have a fast display (like
       xterm),  you  can set it to some higher value. If no argu-
       ment is specified, the current setting is displayed.

       ootthheerr

       Switch to the window displayed previously.

       ppaarrttiiaall oonn|ooffff

       Defines whether the display should be refreshed  (as  done
       with  "C-a l") after switching to the current window. This
       command only affects the current window.   To  affect  all
       windows  use the _a_l_l_p_a_r_t_i_a_l command.  Default is `off', of
       course.

       ppaasssswwoorrdd [_c_r_y_p_t_e_d___p_w]

       Present a crypted password in your  ".screenrc"  file  and
       screen  will  ask  for  it,  whenever  someone attempts to
       resume a detached. This is useful if you  have  privileged
       programs running under _s_c_r_e_e_n and you want to protect your
       session from reattach attempts by another user  masquerad-
       ing as your uid (i.e. any superuser.)  If no crypted pass-
       word is specified, screen prompts twice for typing a pass-
       word and places its encryption in the copybuffer.  Default
       is `none', this disables password checking.

       ppaassttee [_r_e_g_i_s_t_e_r_s]

       Write the contents of the specified registers to the stdin
       queue  of  the current window. The register '.' is treated
       as the paste buffer. If no parameter  is  given  only  the



                            2 Aug 1993                         22





SCREEN(1)                                               SCREEN(1)


       paste  buffer  is  used.   It can be filled with the _c_o_p_y,
       _h_i_s_t_o_r_y and _r_e_a_d_b_u_f commands.

       ppooww__bbrreeaakk

       Reopen the window's terminal line and send a break  condi-
       tion. See `break'.

       ppooww__ddeettaacchh

       Power detach.  Mainly the same as _d_e_t_a_c_h, but also sends a
       HANGUP signal to the parent process of  _s_c_r_e_e_n.   CAUTION:
       This will result in a logout, when _s_c_r_e_e_n was started from
       your login shell.

       ppooww__ddeettaacchh__mmssgg _m_e_s_s_a_g_e

       The _m_e_s_s_a_g_e specified here is  output  whenever  a  `Power
       detach' was performed. It may be used as a replacement for
       a logout message or to reset baud rate, etc.

       pprreevv

       Switch to the window with the  next  lower  number.   This
       command  can  be used repeatedly to cycle through the list
       of windows.

       pprroocceessss [_k_e_y]

       Stuff the contents of the specified register into  creen's
       input  queue. If no argument is given you are prompted for
       a register name. The text is parsed  as  if  it  had  been
       typed in from the users keyboard. This command can be used
       to bind multiple actions to a single key.

       qquuiitt

       Kill all windows  and  terminate  _s_c_r_e_e_n.   Note  that  on
       vt100-style  terminals the keys C-4 and C-\ are identical.
       This makes the default bindings dangerous: Be careful  not
       to  type  C-a  C-4  when  selecting window no. 4.  Use the
       empty bind command (as in "bind '^\'")  to  remove  a  key
       binding.

       rreeaaddbbuuff

       Reads  the  contents  of  the current screen-exchange file
       into the copy buffer.  See also "bufferfile" command.

       rreeddiissppllaayy

       Redisplay the current window. Needed to get a full  redis-
       play when in partial redraw mode.




                            2 Aug 1993                         23





SCREEN(1)                                               SCREEN(1)


       rreeggiisstteerr _k_e_y _s_t_r_i_n_g

       Save  the  specified  _s_t_r_i_n_g to the register _k_e_y. See also
       the "ins_reg" command.

       rreemmoovveebbuuff

       Unlinks the screen-exchange  file  used  by  the  commands
       "writebuf" and "readbuf".

       rreesseett

       Reset  the virtual terminal to its "power-on" values. Use-
       ful when strange settings (like scroll regions or graphics
       character set) are left over from an application.

       ssccrreeeenn [_-_o_p_t_s] [_n] [_c_m_d [_a_r_g_s]]

       Establish a new window.  The flow-control options (--ff, --ffnn
       and --ffaa), title (a.k.a.) option (--tt),  login  options  (--ll
       and --llnn) , terminal type option (--TT <<tteerrmm>>) and scrollback
       option (--hh <num>) may be specified for each  command.   If
       an  optional number _n in the range 0..9 is given, the win-
       dow number _n is assigned to the newly created window  (or,
       if  this number is already in-use, the next available num-
       ber).  If a command is specified after "screen", this com-
       mand  (with the given arguments) is started in the window;
       otherwise, a shell is created.  Thus, if your  ".screenrc"
       contains the lines

                   # example for .screenrc:
                   screen 1
                   screen -fn -t foobar 2 telnet foobar

       _s_c_r_e_e_n  creates a shell window (in window #1) and a window
       with a TELNET connection to the machine  foobar  (with  no
       flow-control using the title "foobar" in window #2). Note,
       that unlike previous  versions  of  _s_c_r_e_e_n  no  additional
       default  window  is  created  when  "screen"  commands are
       included in your ".screenrc" file. When the initialization
       is completed, _s_c_r_e_e_n switches to the last window specified
       in your .screenrc file or, if none, opens a default window
       #0.

       ssccrroollllbbaacckk _n_u_m

       Set the size of the scrollback buffer for the current win-
       dows to _n_u_m lines. The default scrollback  is  100  lines.
       See  also  the  "defscrollback" command and use "C-a i" to
       view the current setting.

       sseelleecctt [_n]

       Switch to the window with the  number  _n.   If  no  window



                            2 Aug 1993                         24





SCREEN(1)                                               SCREEN(1)


       number  is  specified, you get prompted for an identifier.
       This can be title (alphanumeric window name) or a  number.
       When a new window is established, the first available num-
       ber is assigned to this window.  Thus,  the  first  window
       can  be activated by "select 0" (there can be no more than
       10 windows present simultaneously unless  screen  is  com-
       piled with a higher MAXWIN setting).

       sseessssiioonnnnaammee [_n_a_m_e]

       Rename  the current session. Note, that for "screen -list"
       the name shows up with the process-id  prepended.  If  the
       argument  "name"  is  omitted, the name of this session is
       displayed. Caution: The $STY environment  variables  still
       reflects  the old name. This may result in confusion.  The
       default is constructed from the tty and host names.

       sseetteennvv [_v_a_r [_s_t_r_i_n_g]]

       Set the environment variable _v_a_r to value _s_t_r_i_n_g.  If only
       _v_a_r  is  specified,  the  user will be prompted to enter a
       value.  If no parameters are specified, the user  will  be
       prompted  for  both variable and value. The environment is
       inherited by all subsequently forked shells.

       sshheellll _c_o_m_m_a_n_d

       Set the command to be used to create a  new  shell.   This
       overrides  the  value  of the environment variable $SHELL.
       This is useful if you'd like to run a  tty-enhancer  which
       is  expecting  to execute the program specified in $SHELL.
       If the command begins with a '-' character, the shell will
       be started as a login-shell.

       sshheellllttiittllee _t_i_t_l_e

       Set  the title for all shells created during startup or by
       the C-A C-c command.  For details about what a  title  is,
       see the discussion entitled "TITLES (naming windows)".

       ssiilleennccee [oonn|ooffff|_s_e_c]

       Toggles  silence  monitoring  of windows.  When silence is
       turned on and an affected  window  is  switched  into  the
       background, you will receive the silence notification mes-
       sage in the status line after a specified period of  inac-
       tivity  (silence). The default timeout can be changed with
       the `silencewait' command or by  specifying  a  number  of
       seconds  instead  of  `on' or `off'.  Silence is initially
       off for all windows.

       ssiilleenncceewwaaiitt _s_e_c

       Define the time that all  windows  monitored  for  silence



                            2 Aug 1993                         25





SCREEN(1)                                               SCREEN(1)


       should  wait  before displaying a message. Default 30 sec-
       onds.

       sslleeeepp _n_u_m

       This command will pause the execution of a .screenrc  file
       for  _n_u_m  seconds.   Keyboard activity will end the sleep.
       It may be used to give users a chance to read the messages
       output by "echo".

       sslloowwppaassttee _u_s_e_c

       Define  the  speed  at which text is inserted by the paste
       ("C-a ]") command.  If the slowpaste value is nonzero text
       is  written  character  by  character.  _s_c_r_e_e_n will make a
       pause of _u_s_e_c milliseconds after each write to  allow  the
       application  to  process  its input. Only use slowpaste if
       your underlying system exposes flow control problems while
       pasting large amounts of text.

       ssttaarrttuupp__mmeessssaaggee oonn|ooffff

       Select whether you want to see the copyright notice during
       startup.  Default is `on', as you propably noticed.

       ssuussppeenndd

       Suspend _s_c_r_e_e_n.  The windows are in the `detached'  state,
       while  _s_c_r_e_e_n  is  suspended.  This  feature relies on the
       shell being able to do job control.

       tteerrmm _t_e_r_m

       In each window's environment _s_c_r_e_e_n opens, the $TERM vari-
       able  is set to "screen" by default.  But when no descrip-
       tion for "screen" is installed in  the  local  termcap  or
       terminfo data base, you set $TERM to - say - "vt100". This
       won't do much harm, as _s_c_r_e_e_n  is  VT100/ANSI  compatible.
       The  use  of  the  "term"  command is discouraged for non-
       default purpose.  That is, one may want to specify special
       $TERM  settings  (e.g.  vt100) for the next "screen rlogin
       othermachine" command. Use the command  "screen  -T  vt100
       rlogin  othermachine"  rather  than setting ("term vt100")
       and resetting ("term screen") the default before and after
       the "screen" command.

       tteerrmmccaapp _t_e_r_m _t_e_r_m_i_n_a_l_-_t_w_e_a_k_s [_w_i_n_d_o_w_-_t_w_e_a_k_s]
       tteerrmmiinnffoo _t_e_r_m _t_e_r_m_i_n_a_l_-_t_w_e_a_k_s [_w_i_n_d_o_w_-_t_w_e_a_k_s]

       Use  this  command to modify your terminal's termcap entry
       without going through all the hassles involved in creating
       a  custom  termcap  entry.   Plus, you can optionally cus-
       tomize the termcap generated for  the  windows.   If  your
       system  works  with  terminfo-database  rather  than  with



                            2 Aug 1993                         26





SCREEN(1)                                               SCREEN(1)


       termcap, _s_c_r_e_e_n will understand  the  `terminfo'  command,
       which  has the same effects as the `termcap' command. Thus
       users can write  one  .screenrc  file  that  handles  both
       cases, although terminfo syntax is slightly different from
       termcap syntax.

       The first argument specifies which terminal(s)  should  be
       affected  by  this  definition.   You can specify multiple
       terminal names by separating them with `|'s.  Use  `*'  to
       match  all terminals and `vt*' to match all terminals that
       begin with "vt".

       Each _t_w_e_a_k argument contains one or more  termcap  defines
       (separated  by  `:'s)  to  be inserted at the start of the
       appropriate termcap  entry,  enhancing  it  or  overriding
       existing values.  The first tweak modifies your terminal's
       termcap, and contains definitions that your terminal  uses
       to  perform  certain  functions.  Specify a null string to
       leave this unchanged (e.g.  '').   The  second  (optional)
       tweak modifies all the window termcaps, and should contain
       definitions that screen understands (see the "VIRTUAL TER-
       MINAL" section).

       Some examples:

              termcap xterm*  LP:hs@

       Informs  _s_c_r_e_e_n that all terminals that begin with `xterm'
       have firm auto-margins that allow the last position on the
       screen  to  be  updated (LP), but they don't really have a
       status line (no 'hs' - append `@' to  turn  entries  off).
       Note that we assume `LP' for all terminal names that start
       with "vt", but only if you don't specify a termcap command
       for that terminal.

              termcap     vt*      LP     termcap     vt102|vt220
              Z0=\E[?3h:Z1=\E[?3l

       Specifies the firm-margined `LP' capability for all termi-
       nals  that  begin with `vt', and the second line will also
       add the escape-sequences to switch into (Z0) and back  out
       of  (Z1) 132-character-per-line mode if this is a vt102 or
       vt220.  (You must specify Z0 and Z1 in your termcap to use
       the width-changing commands.)

              termcap vt100  ""  l0=PF1:l1=PF2:l2=PF3:l3=PF4

       This leaves your vt100 termcap alone and adds the function
       key labels to each window's termcap entry.

              termcap h19|z19  am@:im=\E@:ei=\EO  dc=\E[P

       Takes a h19 or z19  termcap  and  turns  off  auto-margins
       (am@) and enables the insert mode (im) and end-insert (ei)



                            2 Aug 1993                         27





SCREEN(1)                                               SCREEN(1)


       capabilities (the `@' in the `im' string is after the `=',
       so  it  is  part of the string).  Having the `im' and `ei'
       definitions put into your terminal's  termcap  will  cause
       screen  to  automatically  advertise  the character-insert
       capability in each window's  termcap.   Each  window  will
       also get the delete-character capability (dc) added to its
       termcap, which screen will translate  into  a  line-update
       for  the  terminal  (we're  pretending  it doesn't support
       character deletion).

       If you would like to fully specify each  window's  termcap
       entry,  you  should  instead  set  the $SCREENCAP variable
       prior to running _s_c_r_e_e_n.  See the discussion on the  "VIR-
       TUAL TERMINAL" in this manual, and the termcap(5) man page
       for more information on termcap definitions.

       ttiimmee

       Uses the message line to display the time of day, the host
       name,  and the load averages over 1, 5, and 15 minutes (if
       this is available on your system).   For  window  specific
       information use "info".

       ttiittllee [_w_i_n_d_o_w_a_l_i_a_s]

       Set  the  name of the current window to _w_i_n_d_o_w_a_l_i_a_s. If no
       name is specified, screen prompts for  one.  This  command
       was known as `aka' in previous releases.

       uunnsseetteennvv _v_a_r

       Unset an environment variable.

       vvbbeellll oonn|ooffff

       If your terminal does not support a visual bell, a `vbell-
       message' is displayed in the status line.  Sets the visual
       bell  setting  for  this window. If your terminal does not
       support a visual bell, a `vbell-message' is  displayed  in
       the status line.  Refer to the termcap variable `vb' (ter-
       minfo: 'flash').

       vvbbeellll__mmssgg _m_e_s_s_a_g_e

       Sets the visual bell message. _m_e_s_s_a_g_e is  printed  to  the
       status  line  if the window receives a bell character (^G)
       and vbell is set to "on".  The default message  is  "Wuff,
       Wuff!!".

       vvbbeellllwwaaiitt _s_e_c

       Define  a  delay in seconds after each display of _s_c_r_e_e_n's
       visual bell message. The default is 1 second.




                            2 Aug 1993                         28





SCREEN(1)                                               SCREEN(1)


       vveerrssiioonn

       Print the current version and the compile date in the sta-
       tus line.

       wwaallll _m_e_s_s_a_g_e _._._.

       Write  a  message to all displays. The message will appear
       in the terminals status line.

       wwiiddtthh [_n_u_m]

       Toggle the window width between 80 and 132 columns or  set
       it  to  _n_u_m  columns  if  an  argument is specified.  This
       requires a capable terminal and the termcap  entries  "Z0"
       and "Z1".  See the "termcap" command for more information.

       wwiinnddoowwss

       Uses the message line to display a list of  all  the  win-
       dows.   Each  window  is listed by number with the name of
       process that has  been  started  in  the  window  (or  its
       title);  the current window is marked with a `*'; the pre-
       vious window is marked with a `-'; all  the  windows  that
       are "logged in" are marked with a `$'; a background window
       that has received a bell is marked with  a  `!';  a  back-
       ground window that is being monitored and has had activity
       occur is marked with an `@'; a  window  which  has  output
       logging  turned  on is marked with `(L)'; windows occupied
       by other users are marked with `&'; windows in the  zombie
       state  are  marked  with `Z'.  If this list is too long to
       fit on the terminals status line only the  portion  around
       the current window is displayed.

       wwrraapp [oonn|ooffff]

       Sets  the  line-wrap setting for the current window.  When
       line-wrap is on, the second consecutive printable  charac-
       ter  output  at the last column of a line will wrap to the
       start  of  the  following  line.   As  an  added  feature,
       backspace  (^H)  will also wrap through the left margin to
       the previous line.  Default is `on'.

       wwrriitteebbuuff

       Writes the contents of the paste buffer to a public acces-
       sible screen-exchange file. This is thought of as a primi-
       tive means of communication between _s_c_r_e_e_n  users  on  the
       same  host.  The  filename  can be set with the _b_u_f_f_e_r_f_i_l_e
       command and defaults to "/tmp/screen-exchange".

       wwrriitteelloocckk _[oonn_|ooffff_|aauuttoo_]

       In addition to access control lists, not all users may  be



                            2 Aug 1993                         29





SCREEN(1)                                               SCREEN(1)


       able  to  write  to  the same window at once. Per default,
       writelock is in `auto' mode  and  grants  exclusive  input
       permission  to  the user who is the first to switch to the
       particular window. When he leaves the window, other  users
       may obtain the writelock (automatically). The writelock of
       the current window is disabled by the  command  "writelock
       off".  If  the  user  issues the command "writelock on" he
       keeps the exclusive write permission  while  switching  to
       other windows.

       xxooffff
       xxoonn

       Insert  a  CTRL-s / CTRL-q character to the stdin queue of
       the current window.

       zzoommbbiiee [_k_e_y]

       Per default screen windows are  removed  from  the  window
       list  as  soon  as the windows process (e.g. shell) exits.
       When a key is specified to the  zombie  command  a  `dead'
       windows  will  remain in the list until it is selected and
       this key is pressed or the "kill" command is issued.


TTHHEE MMEESSSSAAGGEE LLIINNEE
       _S_c_r_e_e_n displays informational messages and other  diagnos-
       tics in a _m_e_s_s_a_g_e _l_i_n_e.  While this line is distributed to
       appear at the bottom of the screen, it can be  defined  to
       appear  at  the  top of the screen during compilation.  If
       your terminal has a status line defined  in  its  termcap,
       screen  will  use this for displaying its messages, other-
       wise a line of the  current  screen  will  be  temporarily
       overwritten  and  output  will be momentarily interrupted.
       The message line is automatically removed after a few sec-
       onds delay, but it can also be removed early (on terminals
       without a status line) by beginning to type.

       The message line facility can be used  by  an  application
       running in the current window by means of the ANSI _P_r_i_v_a_c_y
       _m_e_s_s_a_g_e control sequence.  For instance, from  within  the
       shell, try something like:

              echo   '<esc>^Hello   world   from   window  '$WIN-
              DOW'<esc>\\'

       where '<esc>' is an _e_s_c_a_p_e, '^' is a literal up-arrow, and
       '\\' turns into a single backslash.



FFLLOOWW--CCOONNTTRROOLL
       Each window has a flow-control setting that determines how
       screen deals with the XON and XOFF characters (and perhaps



                            2 Aug 1993                         30





SCREEN(1)                                               SCREEN(1)


       the  interrupt  character).   When  flow-control is turned
       off, screen ignores the XON  and  XOFF  characters,  which
       allows  the  user  to  send them to the current program by
       simply typing them  (useful  for  the  _e_m_a_c_s  editor,  for
       instance).   The trade-off is that it will take longer for
       output from a "normal" program to pause in response to  an
       XOFF.   With  flow-control turned on, XON and XOFF charac-
       ters are used to immediately pause the output of the  cur-
       rent  window.   You can still send these characters to the
       current program, but you must  use  the  appropriate  two-
       character screen commands (typically "C-a q" (xon) and "C-
       a s" (xoff)).  The xon/xoff commands are also  useful  for
       typing  C-s  and C-q past a terminal that intercepts these
       characters.

       Each window has an initial  flow-control  value  set  with
       either  the  --ff option or the "defflow" .screenrc command.
       Per  default  the  windows  are  set  to  automatic  flow-
       switching.   It  can  then  be  toggled  between the three
       states 'fixed on', 'fixed off'  and  'automatic'  interac-
       tively with the "flow" command bound to "C-a f".

       The  automatic flow-switching mode deals with flow control
       using the TIOCPKT mode (like "rlogin" does).  If  the  tty
       driver  does not support TIOCPKT, screen tries to find out
       the right mode based on the current setting of the  appli-
       cation keypad - when it is enabled, flow-control is turned
       off and visa versa.  Of course, you can  still  manipulate
       flow-control manually when needed.

       If  you're running with flow-control enabled and find that
       pressing the interrupt key (usually C-c) does  not  inter-
       rupt the display until another 6-8 lines have scrolled by,
       try running screen with the "interrupt"  option  (add  the
       "interrupt"  flag to the "flow" command in your .screenrc,
       or use the --ii command-line option).  This causes the  out-
       put  that _s_c_r_e_e_n has accumulated from the interrupted pro-
       gram to be flushed.  One disadvantage is that the  virtual
       terminal's  memory contains the non-flushed version of the
       output, which in rare cases can cause  minor  inaccuracies
       in  the  output.   For  example, if you switch screens and
       return, or update the screen with "C-a l"  you  would  see
       the  version  of  the output you would have gotten without
       "interrupt" being on.  Also, you might need  to  turn  off
       flow-control  (or  use auto-flow mode to turn it off auto-
       matically) when running a program that expects you to type
       the  interrupt  character  as  input, as it is possible to
       interrupt the output of the virtual terminal to your phys-
       ical  terminal when flow-control is enabled.  If this hap-
       pens, a simple refresh of the screen  with  "C-a  l"  will
       restore  it.  Give each mode a try, and use whichever mode
       you find more comfortable.





                            2 Aug 1993                         31





SCREEN(1)                                               SCREEN(1)


TTIITTLLEESS ((nnaammiinngg wwiinnddoowwss))
       You can customize each window's name in the window display
       (viewed  with the "windows" command (C-a w)) by setting it
       with one of the title commands.  Normally  the  name  dis-
       played  is  the actual command name of the program created
       in the window.  However, it is sometimes useful to distin-
       guish  various  programs of the same name or to change the
       name on-the-fly to reflect the current state of  the  win-
       dow.

       The default name for all shell windows can be set with the
       "shelltitle" command in  the  .screenrc  file,  while  all
       other windows are created with a "screen" command and thus
       can have their name set  with  the  --tt  option.   Interac-
       tively,   there   is   the   title-string  escape-sequence
       (<esc>k_n_a_m_e<esc>\) and the "title" command (C-a  A).   The
       former  can  be  output from an application to control the
       window's name under software control, and the latter  will
       prompt  for  a  name  when  typed.  You can also bind pre-
       defined names to keys with  the  "title"  command  to  set
       things quickly without prompting.

       Finally,  _s_c_r_e_e_n  has  a  shell-specific heuristic that is
       enabled by setting the window's name to "_s_e_a_r_c_h_|_n_a_m_e"  and
       arranging to have a null title escape-sequence output as a
       part of your prompt.  The _s_e_a_r_c_h portion specifies an end-
       of-prompt  search string, while the _n_a_m_e portion specifies
       the default shell name for the window.  If the  _n_a_m_e  ends
       in  a  `:' _s_c_r_e_e_n will add what it believes to be the cur-
       rent command running in the window to the end of the  win-
       dow's shell name (e.g. "_n_a_m_e_:_c_m_d").  Otherwise the current
       command name supersedes the shell name while  it  is  run-
       ning.

       Here's how it works:  you must modify your shell prompt to
       output a null title-escape-sequence  (<esc>k<esc>\)  as  a
       part of your prompt.  The last part of your prompt must be
       the same as the string you specified for the  _s_e_a_r_c_h  por-
       tion  of  the title.  Once this is set up, _s_c_r_e_e_n will use
       the title-escape-sequence to clear  the  previous  command
       name  and  get  ready  for the next command.  Then, when a
       newline is received from the shell, a search is  made  for
       the  end  of the prompt.  If found, it will grab the first
       word after the matched string and use it  as  the  command
       name.  If the command name begins with either '!', '%', or
       '^' _s_c_r_e_e_n will use the first word on the  following  line
       (if  found)  in  preference  to the just-found name.  This
       helps csh users get better command names  when  using  job
       control or history recall commands.

       Here's some .screenrc examples:

              screen -t top 2 nice top




                            2 Aug 1993                         32





SCREEN(1)                                               SCREEN(1)


       Adding  this  line  to your .screenrc would start a nice-d
       version of the "top" command in window 2 name "top" rather
       than "nice".

                   shelltitle '> |csh'
                   screen 1

       These commands would start a shell with the given shellti-
       tle.  The title specified  is  an  auto-title  that  would
       expect  the prompt and the typed command to look something
       like the following:

              /usr/joe/src/dir> trn

       (it looks after the '> ' for the command name).  The  win-
       dow status would show the name "trn" while the command was
       running, and revert to "csh" upon completion.

              bind R screen -t '% |root:' su

       Having this command in your .screenrc would bind  the  key
       sequence  "C-a R" to the "su" command and give it an auto-
       title name of "root:".  For this auto-title to  work,  the
       screen could look something like this:

                   % !em
                   emacs file.c

       Here  the  user  typed the csh history command "!em" which
       ran the previously entered "emacs"  command.   The  window
       status would show "root:emacs" during the execution of the
       command, and revert to simply "root:" at its completion.

                   bind o title
                   bind E title ""
                   bind u title (unknown)

       The first binding doesn't have any arguments, so it  would
       prompt you for a title. when you type "C-a o".  The second
       binding would clear an auto-title's current  setting  (C-a
       E).   The  third  binding  would  set the current window's
       title to "(unknown)" (C-a u).

       One thing to keep in mind when adding a null title-escape-
       sequence to your prompt is that some shells (like the csh)
       count all  the  non-control  characters  as  part  of  the
       prompt's  length.   If these invisible characters aren't a
       multiple of 8 then backspacing over a tab will  result  in
       an  incorrect  display.   One way to get around this is to
       use a prompt like this:

              set prompt='^[[0000m^[k^[\% '

       The escape-sequence "<esc>[0000m" not only normalizes  the



                            2 Aug 1993                         33





SCREEN(1)                                               SCREEN(1)


       character  attributes,  but all the zeros round the length
       of the invisible characters up  to  8.   Bash  users  will
       probably   want   to  echo  the  escape  sequence  in  the
       PROMPT_COMMAND:

              PROMPT_COMMAND='echo -n -e "\033k\033\134"'

       (I used "134" to output a `\' because of  a  bug  in  bash
       v1.04).



TTHHEE VVIIRRTTUUAALL TTEERRMMIINNAALL
       Usually  _s_c_r_e_e_n tries to emulate as much of the VT100/ANSI
       standard as possible. But if your terminal  lacks  certain
       capabilities,  the emulation may not be complete. In these
       cases _s_c_r_e_e_n has to tell the applications that some of the
       features are missing. This is no problem on machines using
       termcap, because _s_c_r_e_e_n can use the $TERMCAP  variable  to
       customize the standard screen termcap.

       But  if you do a rlogin on another machine or your machine
       supports only terminfo this method fails. Because of this,
       _s_c_r_e_e_n offers a way to deal with these cases.  Here is how
       it works:

       When _s_c_r_e_e_n tries  to  figure  out  a  terminal  name  for
       itself, it first looks for an entry named "screen.<term>",
       where <term> is the contents of your $TERM  variable.   If
       no such entry exists, _s_c_r_e_e_n tries "screen" (or "screen-w"
       if the terminal is wide (132 cols or more)).  If even this
       entry cannot be found, "vt100" is used as a substitute.

       The idea is that if you have a terminal which doesn't sup-
       port an important feature (e.g. delete char  or  clear  to
       EOS) you can build a new termcap/terminfo entry for _s_c_r_e_e_n
       (named "screen.<dumbterm>") in which this  capability  has
       been disabled. If this entry is installed on your machines
       you are able to do a rlogin and  still  keep  the  correct
       termcap/terminfo  entry.   The terminal name is put in the
       $TERM variable of all new windows.  _S_c_r_e_e_n also  sets  the
       $TERMCAP  variable reflecting the capabilities of the vir-
       tual terminal emulated. Notice that, however, on  machines
       using  the  terminfo database this variable has no effect.
       Furthermore, the variable $WINDOW is  set  to  the  window
       number of each window.

       The  actual  set  of capabilities supported by the virtual
       terminal depends on  the  capabilities  supported  by  the
       physical  terminal.  If, for instance, the physical termi-
       nal does not support underscore mode, _s_c_r_e_e_n does not  put
       the  `us' and `ue' capabilities into the window's $TERMCAP
       variable, accordingly.  However, a minimum number of capa-
       bilities  must  be supported by a terminal in order to run



                            2 Aug 1993                         34





SCREEN(1)                                               SCREEN(1)


       _s_c_r_e_e_n; namely scrolling, clear screen, and direct  cursor
       addressing  (in  addition, _s_c_r_e_e_n does not run on hardcopy
       terminals or on terminals that over-strike).

       Also, you can customize the $TERMCAP value used by  _s_c_r_e_e_n
       by  using  the "termcap" .screenrc command, or by defining
       the variable $SCREENCAP prior to  startup.   When  the  is
       latter  defined,  its  value  will be copied verbatim into
       each window's $TERMCAP variable.  This can either  be  the
       full terminal definition, or a filename where the terminal
       "screen" (and/or "screen-w") is defined.

       Note that _s_c_r_e_e_n honors the "terminfo"  .screenrc  command
       if the system uses the terminfo database rather than term-
       cap.

       When the boolean `G0' capability is present in the termcap
       entry  for  the  terminal on which _s_c_r_e_e_n has been called,
       the terminal emulation of _s_c_r_e_e_n supports multiple charac-
       ter  sets.  This allows an application to make use of, for
       instance, the VT100 graphics  character  set  or  national
       character  sets.  The following control functions from ISO
       2022 are supported: _l_o_c_k _s_h_i_f_t  _G_0  (_S_I),  _l_o_c_k  _s_h_i_f_t  _G_1
       (_S_O),  _l_o_c_k  _s_h_i_f_t _G_2, _l_o_c_k _s_h_i_f_t _G_3, _s_i_n_g_l_e _s_h_i_f_t _G_2, and
       _s_i_n_g_l_e _s_h_i_f_t _G_3.  When a virtual terminal  is  created  or
       reset, the ASCII character set is designated as _G_0 through
       _G_3.  When the `G0' capability is present, screen evaluates
       the  capabilities `S0', `E0', and `C0' if present. `S0' is
       the sequence the terminal uses to  enable  and  start  the
       graphics character set rather than _S_I.  `E0' is the corre-
       sponding replacement for _S_O. `C0'  gives  a  character  by
       character  translation  string  that  is used during semi-
       graphics mode. This string is built like the  `acsc'  ter-
       minfo capability.

       When  the  `po'  and  `pf' capabilities are present in the
       terminal's termcap entry, applications running in a _s_c_r_e_e_n
       window  can  send output to the printer port of the termi-
       nal.  This allows a user to have  an  application  in  one
       window sending output to a printer connected to the termi-
       nal, while all other windows are still active (the printer
       port  is enabled and disabled again for each chunk of out-
       put).  As a side-effect,  programs  running  in  different
       windows  can  send  output  to the printer simultaneously.
       Data sent to the printer is not displayed in the window.

       Some capabilities are only put into the $TERMCAP  variable
       of  the virtual terminal if they can be efficiently imple-
       mented by  the  physical  terminal.   For  instance,  `dl'
       (delete  line)  is  only put into the $TERMCAP variable if
       the  terminal  supports  either  delete  line  itself   or
       scrolling  regions.  Note that this may provoke confusion,
       when the session is reattached on a different terminal, as
       the  value  of  $TERMCAP  cannot  be  modified  by  parent



                            2 Aug 1993                         35





SCREEN(1)                                               SCREEN(1)


       processes.

       The following is a list of control sequences recognized by
       _s_c_r_e_e_n.  "(V)" and "(A)" indicate VT100-specific and ANSI-
       or ISO-specific functions, respectively.


       EESSCC EE                      Next Line

       EESSCC DD                      Index

       EESSCC MM                      Reverse Index

       EESSCC HH                      Horizontal Tab Set

       EESSCC ZZ                      Send    VT100    Identification
                                  String

       EESSCC 77                 (V)  Save Cursor and Attributes

       EESSCC 88                 (V)  Restore Cursor and Attributes

       EESSCC [[ss                (A)  Save Cursor and Attributes

       EESSCC [[uu                (A)  Restore Cursor and Attributes

       EESSCC cc                      Reset to Initial State

       EESSCC ==                 (V)  Application Keypad Mode

       EESSCC >>                 (V)  Numeric Keypad Mode

       EESSCC ## 88               (V)  Fill Screen with E's

       EESSCC \\                 (A)  String Terminator

       EESSCC ^^                 (A)  Privacy Message String (Message
                                  Line)

       EESSCC !!                      Global Message String  (Message
                                  Line)

       EESSCC kk                      A.k.a. Definition String

       EESSCC PP                 (A)  Device Control String.  Outputs
                                  a string directly to  the  host
                                  terminal   without  interpreta-
                                  tion.

       EESSCC __                 (A)  Application   Program   Command
                                  (not used)

       EESSCC ]]                 (A)  Operating  System  Command (not
                                  used)



                            2 Aug 1993                         36





SCREEN(1)                                               SCREEN(1)


       CCoonnttrrooll--NN             (A)  Lock Shift G1 (SO)

       CCoonnttrrooll--OO             (A)  Lock Shift G0 (SI)

       EESSCC nn                 (A)  Lock Shift G2

       EESSCC oo                 (A)  Lock Shift G3

       EESSCC NN                 (A)  Single Shift G2

       EESSCC OO                 (A)  Single Shift G3

       EESSCC (( Pcs             (A)  Designate character set as G0

       EESSCC )) Pcs             (A)  Designate character set as G1

       EESSCC ** Pcs             (A)  Designate character set as G2

       EESSCC ++ Pcs             (A)  Designate character set as G3

       EESSCC [[ Pn ;; Pn HH            Direct Cursor Addressing

       EESSCC [[ Pn ;; Pn ff            Direct Cursor Addressing

       EESSCC [[ Pn JJ                 Erase in Display

             Pn = None or 00       From Cursor to End of Screen

                  11               From  Beginning  of  Screen  to
                                  Cursor

                  22               Entire Screen

       EESSCC [[ Pn KK                 Erase in Line

             Pn = None or 00       From Cursor to End of Line

                  11               From  Beginning of Line to Cur-
                                  sor

                  22               Entire Line

       EESSCC [[ Pn AA                 Cursor Up

       EESSCC [[ Pn BB                 Cursor Down

       EESSCC [[ Pn CC                 Cursor Right

       EESSCC [[ Pn DD                 Cursor Left

       EESSCC [[ Ps ;;...;; Ps mm        Select Graphic Rendition

             Ps = None or 00       Default Rendition




                            2 Aug 1993                         37





SCREEN(1)                                               SCREEN(1)


                  11               Bold

                  22          (A)  Faint

                  33          (A)  _S_t_a_n_d_o_u_t  Mode  (ANSI:   Itali-
                                  cized)

                  44               Underlined

                  55               Blinking

                  77               Negative Image

                  2222         (A)  Normal Intensity

                  2233         (A)  _S_t_a_n_d_o_u_t Mode off (ANSI: Itali-
                                  cized off)

                  2244         (A)  Not Underlined

                  2255         (A)  Not Blinking

                  2277         (A)  Positive Image

       EESSCC [[ Pn gg                 Tab Clear

             Pn = None or 00       Clear Tab at Current Position

                  33               Clear All Tabs

       EESSCC [[ Pn ;; Pn rr       (V)  Set Scrolling Region

       EESSCC [[ Pn II            (A)  Horizontal Tab

       EESSCC [[ Pn ZZ            (A)  Backward Tab

       EESSCC [[ Pn LL            (A)  Insert Line

       EESSCC [[ Pn MM            (A)  Delete Line

       EESSCC [[ Pn @@            (A)  Insert Character

       EESSCC [[ Pn PP            (A)  Delete Character

       EESSCC [[ Ps ;;...;; Ps hh        Set Mode

       EESSCC [[ Ps ;;...;; Ps ll        Reset Mode

             Ps = 44          (A)  Insert Mode

                  ??11         (V)  Application Cursor Keys

                  ??33         (V)  Change Terminal  Width  to  132
                                  columns



                            2 Aug 1993                         38





SCREEN(1)                                               SCREEN(1)


                  ??55         (V)  Visible  Bell  (_O_n  followed by
                                  _O_f_f)

                  ??66         (V)  _O_r_i_g_i_n Mode

                  ??77         (V)  _W_r_a_p Mode

       EESSCC [[ 55 ii             (A)  Start relay  to  printer  (ANSI
                                  Media Copy)

       EESSCC [[ 44 ii             (A)  Stop  relay  to  printer  (ANSI
                                  Media Copy)

       EESSCC [[ 88 ;; Ph ;; Pw tt        Resize the window to `Ph' lines
                                  and  `Pw' columns (SunView spe-
                                  cial)

       EESSCC [[ cc                    Send    VT100    Identification
                                  String

       EESSCC [[ 66 nn                  Send Cursor Position Report



SSPPEECCIIAALL TTEERRMMIINNAALL CCAAPPAABBIILLIITTIIEESS
       The  following  table  describes all terminal capabilities
       that are recognized by creen aanndd aarree nnoott iinn tthhee tteerrmmccaapp((55))
       mmaannuuaall..


       LLPP   _(_b_o_o_l_)  Terminal has vt100 style margins (`magic mar-
                    gins'). Note that this capability is obsolete
                    because creen uses 'xn' instead.

       ZZ00   _(_s_t_r_)   Change width to 132 columns.

       ZZ11   _(_s_t_r_)   Change width to 80 columns.

       WWSS   _(_s_t_r_)   Resize   display.  This  capability  has  the
                    desired width and height as  arguments.  _S_u_n_-
                    _V_i_e_w_(_t_m_) example: '\E[8;%d;%dt'.

       BB88   _(_s_t_r_)   Tell  creen  to  look out for characters with
                    8th bit set. If such  a  character  is  found
                    creen processes the specified string and than
                    outputs  the  character  with  the  8th   bit
                    stripped  off.  Note that the string can con-
                    tain any esc-sequences known to  creen,  too.
                    (Example: Single Shift G2 = \EN.)

       OOPP   _(_b_o_o_l_)  Don't do a full vt100 style margin emulation.
                    Same as the -O option.

       NNFF   _(_b_o_o_l_)  Terminal doesn't need flow control.  Send  ^S



                            2 Aug 1993                         39





SCREEN(1)                                               SCREEN(1)


                    and  ^Q  direct  to  the application. Same as
                    'flow off'. The opposite of  this  capability
                    is 'xo'.

       GG00   _(_b_o_o_l_)  Terminal can deal with ISO2022 font selection
                    sequences.

       SS00   _(_s_t_r_)   Switch charset 'G0' to the specified charset.
                    Default is '\E(%d'.

       EE00   _(_s_t_r_)   Switch charset 'G0' back to standard charset.
                    Default is '\E(B'.

       CC00   _(_s_t_r_)   Use the string as a conversion table for font
                    '0'.   See   the  'ac'  capability  for  more
                    details.

       CCSS   _(_s_t_r_)   Switch cursorkeys to application mode.

       CCEE   _(_s_t_r_)   Switch cursorkeys back to normal mode.

       AANN   _(_b_o_o_l_)  Turn on autonuke. See the 'autonuke'  command
                    for more details.

       OOLL   _(_n_u_m_)   Set  the  output  buffer limit. See the 'obu-
                    flimit' command for more details.



EENNVVIIRROONNMMEENNTT
       COLUMNS        Number of columns on  the  terminal  (over-
                      rides termcap entry).
       HOME           Directory in which to look for .screenrc.
       ISCREENRC      Alternate user screenrc file.
       LINES          Number  of lines on the terminal (overrides
                      termcap entry).
       LOCKPRG        Screen lock program.
       NETHACKOPTIONS Turns on nethack option.
       PATH           Used for locating programs to run.
       SCREENCAP      For customizing a terminal's TERMCAP value.
       SCREENDIR      Alternate socket directory.
       SCREENRC       Alternate user screenrc file.
       SHELL          Default  shell  program for opening windows
                      (default "/bin/sh").
       STY            Alternate socket name.
       SYSSCREENRC    Alternate system screenrc file.
       TERM           Terminal name.
       TERMCAP        Terminal description.


FFIILLEESS
       $SYSSCREENRC
       /local/etc/screenrc         creen initialization commands
       $ISCREENRC



                            2 Aug 1993                         40





SCREEN(1)                                               SCREEN(1)


       $SCREENRC
       $HOME/.iscreenrc
       $HOME/.screenrc             Read         in          after
                                   /local/etc/screenrc
       $ISCREENDIR/S-<login>
       $SCREENDIR/S-<login>
       /local/screens/S-<login>    Socket directories (default)
       /usr/tmp/screens/S-<login>  Alternate  socket directories.
       <socket directory>/.termcap Written by the "termcap"  out-
                                   put function
       /usr/tmp/screens/screen-exchange
                                   or
       /tmp/screen-exchange        creen `interprocess communica-
                                   tion buffer'
       hardcopy.[0-9]              Screen images created  by  the
                                   hardcopy function
       screenlog.[0-9]             Output  log  files  created by
                                   the log function
       /usr/lib/terminfo/?/*       or
       /etc/termcap                Terminal capability databases
       /etc/utmp                   Login records
       $LOCKPRG                    Program that locks a terminal.


SSEEEE AALLSSOO
       termcap(5), utmp(5), vi(1), captoinfo(1), tic(1)


AAUUTTHHOORRSS
       Originally  created by Oliver Laumann, this latest version
       was produced by Wayne Davison, Juergen Weigert and Michael
       Schroeder.

CCOOPPYYLLEEFFTT
       Copyright      (C)      1993           Juergen     Weigert
       (jnweiger@immd4.informatik.uni-erlangen.de)        Michael
       Schroeder      (mlschroe@immd4.informatik.uni-erlangen.de)
       Copyright (C) 1987 Oliver Laumann
       This program is free software;  you  can  redistribute  it
       and/or modify it under the terms of the GNU General Public
       License as published  by  the  Free  Software  Foundation;
       either version 2, or (at your option) any later version.
       This  program  is  distributed in the hope that it will be
       useful, but WITHOUT ANY WARRANTY; without even the implied
       warranty  of  MERCHANTABILITY  or FITNESS FOR A PARTICULAR
       PURPOSE.  See the GNU  General  Public  License  for  more
       details.
       You  should have received a copy of the GNU General Public
       License along with this program (see the file COPYING); if
       not, write to the Free Software Foundation, Inc., 675 Mass
       Ave, Cambridge, MA 02139, USA.

CCOONNTTRRIIBBUUTTOORRSS
       Ken Beal (kbeal@amber.ssd.csd.harris.com),



                            2 Aug 1993                         41





SCREEN(1)                                               SCREEN(1)


       Rudolf Koenig (rfkoenig@immd4.informatik.uni-erlangen.de),
       Toerless Eckert (eckert@immd4.informatik.uni-erlangen.de),
       Wayne Davison (davison@borland.com),
       Patrick Wolfe (pat@kai.com, kailand!pat),
       Bart Schaefer (schaefer@cse.ogi.edu),
       Nathan Glasser (nathan@brokaw.lcs.mit.edu),
       Larry W. Virden (lvirden@cas.org),
       Howard Chu (hyc@hanauma.jpl.nasa.gov),
       Tim MacKenzie (tym@dibbler.cs.monash.edu.au),
       Markku Jarvinen (mta@{cc,cs,ee}.tut.fi),
       Marc Boucher (marc@CAM.ORG),
       Doug Siebert (dsiebert@isca.uiowa.edu),
       Ken Stillson (stillson@tsfsrv.mitre.org),
       Ian Frechett (frechett@spot.Colorado.EDU),
       Brian Koehmstedt (bpk@gnu.ai.mit.edu),
       Don Smith (djs6015@ultb.isc.rit.edu),
       Frank van der Linden (vdlinden@fwi.uva.nl),
       Martin Schweikert (schweik@cpp.ob.open.de),
       David Vrona (dave@sashimi.lcu.com),
       E. Tye McQueen (tye%spillman.UUCP@uunet.uu.net),
       Matthew Green (phone@coombs.anu.edu.au),
       Christopher Williams (cgw@unt.edu),
       Matt Mosley (mattm@access.digex.net),
       Gregory Neil Shapiro (gshapiro@wpi.WPI.EDU).


VVEERRSSIIOONN
       This is version 3.5.1. Its roots are a merge of  a  custom
       version  2.3PR7  by Wayne Davison and several enhancements
       to Oliver Laumann's version 2.0. Note  that  all  versions
       numbered 2.x are copyright by Oliver Laumann.


BBUUGGSS
       +o  `dm'  (delete  mode) and `xs' are not handled correctly
          (they are ignored). `xn' is treated as  a  magic-margin
          indicator.

       +o  The _G_R set of ISO 2022 is not supported.

       +o  There   is  no  keyboard  input  translation  to  VT100
          sequences.

       +o  It is not possible to change the  environment  variable
          $TERMCAP  when  reattaching  under a different terminal
          type.

       +o  The support of terminfo based systems is very  limited.
          Adding  extra capabilities to $TERMCAP may not have any
          effects.

       +o  _S_c_r_e_e_n does not make use of hardware tabs.

       +o  _S_c_r_e_e_n must be installed as set-uid with owner root  in



                            2 Aug 1993                         42





SCREEN(1)                                               SCREEN(1)


          order  to  be able to correctly change the owner of the
          tty device file for each  window.   Special  permission
          may also be required to write the file "/etc/utmp".

       +o  Entries  in  "/etc/utmp" are not removed when _s_c_r_e_e_n is
          killed with SIGKILL.  This  will  cause  some  programs
          (like "w" or "rwho") to advertise that a user is logged
          on who really isn't.

       +o  _S_c_r_e_e_n may give a strange warning when your tty has  no
          utmp entry.

       +o  Send  bugreports, fixes, enhancements, t-shirts, money,
          beer & pizza to ssccrreeeenn@@uunnii--eerrllaannggeenn..ddee.











































                            2 Aug 1993                         43


.