screen - screen manager with VT100/ANSI terminal emulation

          screen [ -options ] [ cmd [ args ] ]
          screen -r [ [pid.]tty[.host] ]

          Screen 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, several
          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 history
          buffer for each virtual terminal and a copy-and-paste
          mechanism that allows moving text regions between windows.

          When screen 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 normally
          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 windows, 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,
          screen (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, screen 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.  Similarly, 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:

               screen emacs prog.c

          from a shell prompt within a previously created window.
          This will not run another copy of screen, 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 screen, 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 screen is active on your terminal, the
          terminal's own record is removed from the utmp file. See
          also "C-a L".

          Before you begin to use screen 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 tset 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 screen commands and their bindings. Each
          keystroke is discussed in the section "DEFAULT KEY
          BINDINGS". 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 off.  This will ensure an
          accurate and optimal update of the screen in all
          circumstances.  The next best thing is an auto-margin
          terminal 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 screen
          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 shortened by
          using a terminal with insert-character capability.

          If your terminal is of the second type (firm-margined `am'),
          you will want to let screen know about this, since a normal
          termcap doesn't distinguish this type of automatic margins
          from a "true" `am' terminal.  You do this by specifying the
          `LP' capability in your termcap (see the "termcap" .screenrc
          command), or by using the -L command-line option.  Screen
          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 command-line option.  The
          trade-off is that screen will no-longer accurately emulate
          the vt100's line-end quirks (e.g. the screen will scroll
          after putting one character in the last screen position).

          Screen has the following command-line options:

          -a   include all capabilities (with some minor exceptions)
               in each window's termcap, even if screen must redraw
               parts of the display in order to implement a function.

          -A   Adapt the sizes of all windows to the size of the
               current terminal. By default, screen tries to restore
               its old window sizes when attaching to resizeable
               terminals (those with "WS" in its description, e.g.
               suncmd or some xterm).

          -c file
               override the default configuration file from
               "$HOME/.screenrc" to file.

          -d|-D []
               does not start screen, but detaches the elsewhere
               running screen session. It has the same effect as
               typing "C-a d" from screen's controlling terminal. -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

          -e xy
               specifies the command character to be x and the
               character 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.

          -f, -fn, and -fa
               turns flow-control on, off, or "automatic switching
               mode".  This can also be defined through the "defflow"
               .screenrc command.

          -h num
               Specifies the history scrollback buffer to be num lines

          -i   will cause the interrupt key (usually C-c) to interrupt
               the display immediately when flow-control is on.  See
               the "defflow" .screenrc command for details.  The use
               of this option is discouraged.

          -l and -ln
               turns login mode on or off (for /etc/utmp updating).
               This can also be defined through the "deflogin"
               .screenrc command.

          -ls and -list
               does not start screen, but prints a list of
      strings identifying your screen sessions.
               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 -wipe option.

          -L   tells screen 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"

          -m   causes screen to ignore the $STY environment variable.
               With "screen -m" creation of a new session is enforced,
               regardless whether screen is called from within another
               screen session or not.

          -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"

          -r []
               resumes a detached screen session.  No other options
               (except "-d -r" or "-D -r") may be specified, though an
               optional prefix of [pid.] may be needed to
               distinguish between multiple detached screen sessions.

          -R   attempts to resume the first detached screen session it
               finds.  If successful, all other command-line options
               are ignored.  If no detached session exists, starts a
               new session using the specified options, just as if -R
               had not been specified. The option is set by default if
               screen is run as a login-shell.

          -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 sessionname
               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 name
               sets the title (a.k.a.) for the default shell or
               specified program.  See also the "shelltitle" .screenrc

          -v   Print version number.

               does the same as "screen -ls", but removes destroyed
               sessions instead of marking them as `dead'.

          -x   Attach to a not detached screen session. (Multi display

          As mentioned, each screen command consists of a "C-a"
          followed 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-a '
          C-a "       (select)      Prompt for a window name or number
                                    to switch to.

          C-a 0       (select 0)
           ...           ...

          C-a 9       (select 9)    Switch to window number 0 - 9.

          C-a C-a     (other)       Toggle to the window displayed
                                    previously.  Note that this
                                    binding defaults to the command
                                    character typed twice, unless
                                    overridden; for instance, if you
                                    use the option "-e]x", this
                                    function becomes "]]", not "]C-a".

          C-a a       (meta)        Send the command character (C-a)
                                    to window. See escape command.

          C-a A       (title)       Allow the user to enter a name for
                                    the current window.

          C-a b
          C-a C-b     (break)       Send a break to window.

          C-a B       (pow_break)   Reopen the terminal line and send
                                    a break.

          C-a c
          C-a C-c     (screen)      Create a new window with a shell
                                    and switch to that window.

          C-a C       (clear)       Clear the screen.

          C-a d
          C-a C-d     (detach)      Detach screen from this terminal.

          C-a D D     (pow_detach)  Detach and logout.

          C-a f
          C-a C-f     (flow)        Toggle flow on, off or auto.

          C-a C-g     (vbell)       Toggles screen's visual bell mode.

          C-a h       (hardcopy)    Write a hardcopy of the current
                                    window to the file "hardcopy.n".

          C-a H       (log)         Begins/ends logging of the current
                                    window to the file "screenlog.n".

          C-a i
          C-a C-i     (info)        Show info about this window.

          C-a k
          C-a C-k     (kill)        Destroy current window.

          C-a l
          C-a C-l     (redisplay)   Fully refresh current window.
          C-a L       (login)       Toggle this windows login slot.
                                    Available only if screen is
                                    configured to update the utmp

          C-a m
          C-a C-m     (lastmsg)     Repeat the last message displayed
                                    in the message line.

          C-a M       (monitor)     Toggles monitoring of the current

          C-a space
          C-a n
          C-a C-n     (next)        Switch to the next window.

          C-a N       (number)      Show the number (and title) of the
                                    current window.

          C-a backspace
          C-a h
          C-a p
          C-a C-p     (prev)        Switch to the previous window
                                    (opposite of C-a n).

          C-a q
          C-a C-q     (xon)         Send a control-q to the current

          C-a r
          C-a C-r     (wrap)        Toggle the current window's line-
                                    wrap setting (turn the current
                                    window's automatic margins on and

          C-a s
          C-a C-s     (xoff)        Send a control-s to the current

          C-a t
          C-a C-t     (time)        Show system information.

          C-a v
          C-a C-v     (version)     Display the version and
                                    compilation date.

          C-a w
          C-a C-w     (windows)     Show a list of window.

          C-a W       (width)       Toggle 80/132 columns.

          C-a x
          C-a C-x     (lockscreen)  Lock this terminal.

          C-a z
          C-a C-z     (suspend)     Suspend

          C-a Z       (reset)       Reset the virtual terminal to its
                                    "power-on" values.

          C-a .       (dumptermcap) Write out a ".termcap" file.

          C-a ?       (help)        Show key bindings.

          C-a C-\     (quit)        Kill all windows and terminate

          C-a :       (colon)       Enter command line mode.

          C-a [
          C-a C-[
          C-a esc     (copy)        Enter copy/scrollback mode.

          C-a ]       (paste)       Write the contents of the paste
                                    buffer to the stdin queue of the
                                    current window.

          C-a {
          C-a }       (history)     Copy and paste a previous
                                    (command) line.

          C-a >       (writebuf)    Write pastebuffer to a file.

          C-a <       (readbuf)     Reads the screen-exchange file
                                    into the pastebuffer.

          C-a =       (removebuf)   Removes the file used by C-a < and
                                    C-a >.

          C-a ,       (license)     Shows where screen comes from,
                                    where it went to and why you can
                                    use it.

          C-a _       (silence)     Start/stop monitoring the current
                                    window for inactivity.

          The "socket directory" defaults either to $HOME/.screen or
          simply to /tmp/screens or preferably to /usr/local/screens
          chosen at compile-time. If screen is installed setuid-root,
          then the administrator should compile screen with an
          adequate (not NFS mounted) socket directory. If screen is
          not running setuid-root, the user can specify any mode 777
          directory in the environment variable $SCREENDIR.

          When screen is invoked, it executes initialization commands
          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 following ways: For
          the global screenrc file screen searches for the environment
          variable $SYSSCREENRC (this override feature may be disabled
          at compile-time). The user specific screenrc file is
          searched in $ISCREENRC, then $SCREENRC, then
          $HOME/.iscreenrc and finally defaults to $HOME/.screenrc.
          The command line option -c takes precedence 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 screen 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 previous screen 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 current

          The following commands are available:

          acladd username

          Enable a user to (fully) access this screen session.
          Necessary to allow other users to attach to this screen
          session. Same as `aclchg username +rwx "#?"'. Multi user
          mode only.

          aclchg username permbits list

          Change a users permissions. Permission bits are represented
          as `r', `w' and `x'.  Prefixing `+' grants the permission,
          `-' 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 windows, `?' 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 currently ignored.
          Multi user mode only.

          acldel username

          Remove a user from screens access control list. If currently
          attached, all the users displays are detached from the
          session. He cannot attach again. Multi user mode only.

          activity message

          When any activity occurs in a background window that is
          being monitored, screen displays a notification in the
          message line.  The notification message can be re-defined by
          means of the "activity" command.  Each occurrence of `%' in
          message 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 (usually
          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).

          allpartial on|off

          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".

          at [identifier][#|*|%] command [args ... ]

          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 command. If the
          first parameter describes a non-unique context, the command
          will be executed multiple times. If the first parameter is
          of the form `identifier*' then identifier is matched against
          user names.  The command is executed once for each display
          of the selected user(s). If the first parameter is of the
          form `identifier%' identifier 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 identifier 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 windows because a prefix-match is performed.
          Note that on the affected display(s) a short message will
          describe what happened.

          autodetach on|off

          Sets whether screen will automatically detach upon hangup,
          which saves all your running programs until they are resumed
          with a screen -r command.  When turned off, a hangup signal
          will terminate screen and all the processes it contains.
          Autodetach is on by default.

          autonuke on|off

          Sets whether a clear screen sequence should nuke all the
          output that has not been written to the terminal. See also

          bell message

          When a bell character is sent to a background window, screen
          displays a notification in the message line.  The
          notification message can be re-defined by means of the
          "bell" command.  Each occurrence of `%' in message 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 "").

          bind key [command [args]]

          Bind a command to a key.  By default, most of the commands
          provided by screen are bound to one or more keys as
          indicated in the "DEFAULT KEY BINDINGS" section, e.g. the
          command to create a new window is bound to "C-c" and "c".
          The "bind" command can be used to redefine the key bindings
          and to define new bindings.  The key 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 command 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 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 connection 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.

          break [duration]

          Send a break signal for duration*0.25 seconds to this
          window.  Most useful if a character device is attached to
          the window rather than a shell process.

          bufferfile [exchange-file]

          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

          chdir [directory]

          Change the current directory of screen 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"
          command 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 screen was invoked.  Hardcopy and log files are always
          written to the window's default directory, not 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


          Clears the current window and saves its image to the
          scrollback buffer.


          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" keyword
          no longer exists! Usually commands affect the current 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 screen, you
          may regard "C-a esc" (copy mode) as its `Vi command mode'.

          console [on|off]

          Grabs or ungrabs the machines console output to a window.


          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
          Movement keys:
            h, j, k, l move the cursor line by line or column by
            0, ^ and $ move to the leftmost column, to the first or
              last non-whitespace character on the line.
            H, M and 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 moves to the specified absolute line (default: end of
            | moves to the specified absolute column.
            w, b, e move the cursor word by word.
            C-u and C-d scroll the display up/down by the specified
              amount of lines while preserving the cursor position.
              (Default: half screen-full).
            C-b and C-f scroll the display up/down a full screen.
            g moves to the beginning of the buffer.
            % jumps to the specified percentage of the buffer.

              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.

              The copy range is specified by setting two marks. The
              text between these marks will be highlighted. Press
            space to set the first or second mark respectively.
            Y and y used to mark one whole line or to mark from start
              of line.
            W marks exactly one word.
          Repeat count:
              Any of these commands can be prefixed with a repeat
              count number by pressing digits
            0..9 which is taken as a repeat count.
              Example: "C-a C-[ H 10 j 5 Y" will copy lines 11 to 15
              into the pastebuffer.
            / Vi-like search forward.
            ? Vi-like search backward.
            C-a s Emacs style incremental search forward.
            C-r Emacs style reverse i-search.
              There are however some keys that act differently than in
              vi.  Vi does not allow one to yank rectangular blocks of
              text, but screen does. Press
            c or 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
              copybuffer, 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 joins lines. It toggles between 3 modes: lines separated
              by a newline character (012), lines glued seamless,
              lines separated by a single whitespace. Note that you
              can prepend the newline character with a carriage return
              character, by issuing a "crlf on".
            v is for all the vi users with ":set numbers" - it toggles
              the left margin between column 9 and 1. Press
            a before the final space key to toggle in append mode.
              Thus the contents of the pastebuffer will not be
              overwritten, but is appended to.
            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  "C-A [ g SPACE G $ >".
            C-g gives information about the current line and column.
            @ does nothing. Does not even exit copy mode.

          copy_reg [key]

          Store the current copybuffer contents in a register
          referenced by key.  If the name is omitted you will be
          prompted to press the key.

          crlf on|off

          This affects the copying of text regions with the `C-a ['
          command. If it is set to `on', lines will be separated by
          the two character sequence `CR' - `LF'. Otherwise (default)
          only `LF' is used.

          debug on|off

          Turns runtime debugging on or off. If screen has been
          compiled with option -DDEBUG debugging available and is
          turned on per default. Note that this command only affects
          debugging output from the main "SCREEN" process.

          defautonuke on|off

          Same as the autonuke command except that the default setting
          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 terminal type.

          defflow on|off|auto [interrupt]

          Same as the flow 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 -fa and -i.

          deflogin on|off

          Same as the login command except that the default setting
          for new windows is changed. This is initialised with `on' as
          distributed (see

          defmode mode

          The mode of each newly allocated pseudo-tty is set to mode.
          Mode is an octal number.  When no "defmode" command is
          given, mode 0622 is used.

          defmonitor on|off

          Same as the monitor command except that the default setting
          for new windows is changed. Initial setting is `off'.

          defobuflimit limit

          Same as the obuflimit command except that the default
          setting 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 terminal

          defscrollback num

          Same as the scrollback command except that the default
          setting for new windows is changed. Initial setting is 100.

          defwrap on|off

          Same as the wrap 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".


          Detach the screen session (disconnect it from the terminal
          and put it into the background).  This returns you to the
          shell where you invoked screen.  A detached screen can be
          resumed by invoking screen with the -r option. (See also
          section "COMMAND-LINE OPTIONS".)


          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 screen
          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 screen for each window.
          For terminfo based systems you will need to run a converter
          like captoinfo and then compile the entry with tic.

          echo [-n] message

          The echo command may be used to annoy screen users with a
          'message of the day'. Typically installed in a global
          /local/etc/screenrc. See also "sleep".  Echo is also useful
          for online checking of environment variables.

          escape xy

          Set the command character to x and the character generating
          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".

          exec [[fdpat] newcommand [args ...]]

          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 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.

          Whitespace between the word `exec' and fdpat and the command
          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 `!'.


               exec ... /bin/sh
               exec /bin/sh

          Creates another shell in the same window, while the orignal
          shell is still running. Output of both shells is displayed
          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

          This adds a pager to the window output. The special
          character `|' is needed to give the user control over the
          pager although it gets its input from the original process.

               !:sed -n s/.*Error.*/\007/p

          Sends window output to both, the user and the sed command.
          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.

          flow [on|off|auto]

          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
          discussion 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'.


          Writes out the currently displayed image to a file
          hardcopy.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.

          hardcopy_append on|off

          If set to "on", screen will append to the "hardcopy.n" files
          created by the command "C-a h", otherwise these files are
          overwritten each time.  Default is `off'.

          hardcopydir directory

          Defines a directory where hardcopy files will be placed. If
          unset hardcopys are dumped in screens current working

          hardstatus [on|off]

          Toggles the use of the terminal's hardware status line. If
          "on", screen 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 termcap/terminfo
          capabilities "hs", "ts", "fs" and "ds" are set properly.
          Default is `on' whenever the "hs" capability is present.
          height [lines]

          Set the display height to a specified number of lines. When
          no argument is given it toggles between 24 and 42 lines


          Not really a online help, but displays a help screen showing
          you all the key bindings.  The first pages list all 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.


          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. Screen allows you to have
          a primitive way of re-calling "the command that started
          ...": You just type the first letter of that command, then
          hit `C-a {' and screen 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).


          Uses the message line to display some information about the
          current window: the cursor position in the form
          "(column,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 character
          set (G0, G1, G2, or G3), and in square brackets the terminal
          character sets that are currently designated as G0 through
          G3.  For system information use the "time" command.

          ins_reg [key]

          Paste contents of register key in current windows input
          stream. See also the "copy_reg" and "register" commands.


          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, screen exits.  Note: Emacs
          users should keep this command in mind, when killing a line.
          It is recommended not to use "C-a" as the screen escape key
          or to rebind kill to "C-a K".


          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 commands
          "msgwait" and "msgminwait" for fine tuning.


          Display the disclaimer page. This is done whenever screen is
          started without options, which should be often enough. See
          also the "startup_message" command.


          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 screen is started) and is executed with the
          user's uid and gid.

          log [on|off]

          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

          logdir directory

          Defines a directory where logfiles will be placed. If unset
          logfiles are written in screens current working directory.

          login [on|off]

          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 should be
          "on" for a screen that runs under suid-root.  Use the
          "deflogin" command to change the default login state for new
          windows. Both commands are only present when screen has been
          compiled with utmp support.

          markkeys string

          This is a method of changing the keymap used for
          copy/history mode.  The string is made up of oldchar=newchar
          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.


          Insert the command character (C-a) in the current window's
          input stream.

          monitor [on|off]

          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

          msgminwait sec

          Defines the time screen delays a new message when one
          message is currently displayed. The default is 1 second.

          msgwait sec

          Defines the time a message is displayed if screen is not
          disturbed by other activity. The default is 5 seconds.

          multiuser on|off

          Switch between singleuser and multiuser mode. Standard
          screen operation is singleuser. In multiuser mode the
          commands `acladd' and `acldel' can be used to enable (and
          disable) other users to access this screen.

          nethack on|off

          Changes the kind of error messages used by screen.  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.
          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


          Switch to the next window.  This command can be used
          repeatedly to cycle through the list of windows.

          number [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.

          obuflimit [limit]

          If the output buffer contains more bytes than the specified
          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 argument
          is specified, the current setting is displayed.


          Switch to the window displayed previously.

          partial on|off

          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 allpartial command.  Default is `off', of

          password [crypted_pw]

          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 screen and you want to protect your session
          from reattach attempts by another user masquerading as your
          uid (i.e. any superuser.) If no crypted password is
          specified, screen prompts twice for typing a password and
          places its encryption in the copybuffer.  Default is `none',
          this disables password checking.

          paste [registers]

          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 paste
          buffer is used.  It can be filled with the copy, history and
          readbuf commands.


          Reopen the window's terminal line and send a break
          condition. See `break'.


          Power detach. Mainly the same as detach, but also sends a
          HANGUP signal to the parent process of screen.  CAUTION:
          This will result in a logout, when screen was started from
          your login shell.

          pow_detach_msg message

          The message 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.


          Switch to the window with the next lower number.  This
          command can be used repeatedly to cycle through the list of

          process [key]

          Stuff the contents of the specified register into screen'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.


          Kill all windows and terminate screen.  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.


          Reads the contents of the current screen-exchange file into
          the copy buffer. See also "bufferfile" command.


          Redisplay the current window. Needed to get a full redisplay
          when in partial redraw mode.

          register key string

          Save the specified string to the register key. See also the
          "ins_reg" command.


          Unlinks the screen-exchange file used by the commands
          "writebuf" and "readbuf".


          Reset the virtual terminal to its "power-on" values. Useful
          when strange settings (like scroll regions or graphics
          character set) are left over from an application.

          screen [-opts] [n] [cmd [args]]

          Establish a new window.  The flow-control options (-f, -fn
          and -fa), title (a.k.a.) option (-t), login options (-l and
          -ln) , terminal type option (-T <term>) and scrollback
          option (-h <num>) may be specified for each command.  If an
          optional number n in the range 0..9 is given, the window
          number n is assigned to the newly created window (or, if
          this number is already in-use, the next available number).
          If a command is specified after "screen", this command (with
          the given arguments) is started in the window; otherwise, a
          shell is created.  Thus, if your ".screenrc" contains the

                      # example for .screenrc:
                      screen 1
                      screen -fn -t foobar 2 telnet foobar

          screen 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 screen no additional
          default window is created when "screen" commands are
          included in your ".screenrc" file. When the initialization
          is completed, screen switches to the last window specified
          in your .screenrc file or, if none, opens a default window

          scrollback num

          Set the size of the scrollback buffer for the current
          windows to num lines. The default scrollback is 100 lines.
          See also the "defscrollback" command and use "C-a i" to view
          the current setting.

          select [n]

          Switch to the window with the number n.  If no window 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 number 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 compiled
          with a higher MAXWIN setting).

          sessionname [name]

          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.

          setenv [var [string]]

          Set the environment variable var to value string.  If only
          var 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.

          shell command

          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.

          shelltitle title

          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)".

          silence [on|off|sec]

          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
          message in the status line after a specified period of
          inactivity (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.

          silencewait sec

          Define the time that all windows monitored for silence
          should wait before displaying a message. Default 30 seconds.

          sleep num

          This command will pause the execution of a .screenrc file
          for num seconds.  Keyboard activity will end the sleep.  It
          may be used to give users a chance to read the messages
          output by "echo".

          slowpaste usec

          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.  screen will make a pause of
          usec 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.

          startup_message on|off

          Select whether you want to see the copyright notice during
          startup.  Default is `on', as you propably noticed.


          Suspend screen.  The windows are in the `detached' state,
          while screen is suspended. This feature relies on the shell
          being able to do job control.

          term term

          In each window's environment screen opens, the $TERM
          variable is set to "screen" by default. But when no
          description 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 screen 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.

          termcap term terminal-tweaks [window-tweaks]
          terminfo term terminal-tweaks [window-tweaks]

          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 customize
          the termcap generated for the windows.  If your system works
          with terminfo-database rather than with termcap, screen 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 tweak 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
          TERMINAL" section).

          Some examples:

               termcap xterm*  LP:hs@

          Informs screen 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

          Specifies the firm-margined `LP' capability for all
          terminals 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)
          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

          If you would like to fully specify each window's termcap
          entry, you should instead set the $SCREENCAP variable prior
          to running screen.  See the discussion on the "VIRTUAL
          TERMINAL" in this manual, and the termcap(5) man page for
          more information on termcap definitions.


          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".

          title [windowalias]

          Set the name of the current window to windowalias. If no
          name is specified, screen prompts for one. This command was
          known as `aka' in previous releases.
          unsetenv var

          Unset an environment variable.

          vbell on|off

          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' (terminfo:

          vbell_msg message

          Sets the visual bell message. message 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,

          vbellwait sec

          Define a delay in seconds after each display of screen's
          visual bell message. The default is 1 second.


          Print the current version and the compile date in the status

          wall message ...

          Write a message to all displays. The message will appear in
          the terminals status line.

          width [num]

          Toggle the window width between 80 and 132 columns or set it
          to num 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.


          Uses the message line to display a list of all the windows.
          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 previous 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 background 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.

          wrap [on|off]

          Sets the line-wrap setting for the current window.  When
          line-wrap is on, the second consecutive printable character
          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'.


          Writes the contents of the paste buffer to a public
          accessible screen-exchange file. This is thought of as a
          primitive means of communication between screen users on the
          same host. The filename can be set with the bufferfile
          command and defaults to "/tmp/screen-exchange".

          writelock [on|off|auto]

          In addition to access control lists, not all users may be
          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


          Insert a CTRL-s / CTRL-q character to the stdin queue of the
          current window.

          zombie [key]

          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.

          Screen displays informational messages and other diagnostics
          in a message line.  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, otherwise 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 seconds 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 Privacy
          message control sequence.  For instance, from within the
          shell, try something like:

               echo '<esc>^Hello world from window '$WINDOW'<esc>\\'

          where '<esc>' is an escape, '^' is a literal up-arrow, and
          '\\' turns into a single backslash.

          Each window has a flow-control setting that determines how
          screen deals with the XON and XOFF characters (and perhaps
          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 emacs 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 characters are used to
          immediately pause the output of the current 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 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

          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
          application 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 interrupt
          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 command-line option).  This causes the output
          that screen has accumulated from the interrupted program 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 automatically) 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 physical terminal when flow-control is
          enabled.  If this happens, 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.

     TITLES (naming windows)
          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 displayed
          is the actual command name of the program created in the
          window.  However, it is sometimes useful to distinguish
          various programs of the same name or to change the name on-
          the-fly to reflect the current state of the window.

          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 option.  Interactively,
          there is the title-string escape-sequence (<esc>kname<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, screen has a shell-specific heuristic that is
          enabled by setting the window's name to "search|name" and
          arranging to have a null title escape-sequence output as a
          part of your prompt.  The search portion specifies an end-
          of-prompt search string, while the name portion specifies
          the default shell name for the window.  If the name ends in
          a `:' screen will add what it believes to be the current
          command running in the window to the end of the window's
          shell name (e.g. "name:cmd").  Otherwise the current command
          name supersedes the shell name while it is running.

          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 search portion of
          the title.  Once this is set up, screen 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 '^' screen 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

          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
          shelltitle.  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 window
          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

               set prompt='^[[0000m^[k^[\% '

          The escape-sequence "<esc>[0000m" not only normalizes the
          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

          Usually screen 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 screen has to tell the applications that some of the
          features are missing. This is no problem on machines using
          termcap, because screen 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,
          screen offers a way to deal with these cases. Here is how it
          When screen 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, screen 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
          support an important feature (e.g. delete char or clear to
          EOS) you can build a new termcap/terminfo entry for screen
          (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.  Screen also sets the
          $TERMCAP variable reflecting the capabilities of the virtual
          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 terminal
          does not support underscore mode, screen does not put the
          `us' and `ue' capabilities into the window's $TERMCAP
          variable, accordingly.  However, a minimum number of
          capabilities must be supported by a terminal in order to run
          screen; namely scrolling, clear screen, and direct cursor
          addressing (in addition, screen does not run on hardcopy
          terminals or on terminals that over-strike).

          Also, you can customize the $TERMCAP value used by screen 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 screen honors the "terminfo" .screenrc command if
          the system uses the terminfo database rather than termcap.

          When the boolean `G0' capability is present in the termcap
          entry for the terminal on which screen has been called, the
          terminal emulation of screen supports multiple character
          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: lock shift G0 (SI), lock shift G1 (SO),
          lock shift G2, lock shift G3, single shift G2, and single
          shift G3.  When a virtual terminal is created or reset, the
          ASCII character set is designated as G0 through G3.  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 SI. `E0' is the corresponding
          replacement for SO. `C0' gives a character by character
          translation string that is used during semi-graphics mode.
          This string is built like the `acsc' terminfo capability.

          When the `po' and `pf' capabilities are present in the
          terminal's termcap entry, applications running in a screen
          window can send output to the printer port of the terminal.
          This allows a user to have an application in one window
          sending output to a printer connected to the terminal, while
          all other windows are still active (the printer port is
          enabled and disabled again for each chunk of output).  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 implemented
          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 processes.

          The following is a list of control sequences recognized by
          screen.  "(V)" and "(A)" indicate VT100-specific and ANSI-
          or ISO-specific functions, respectively.

          ESC E                      Next Line

          ESC D                      Index

          ESC M                      Reverse Index

          ESC H                      Horizontal Tab Set

          ESC Z                      Send VT100 Identification String

          ESC 7                 (V)  Save Cursor and Attributes

          ESC 8                 (V)  Restore Cursor and Attributes

          ESC [s                (A)  Save Cursor and Attributes

          ESC [u                (A)  Restore Cursor and Attributes

          ESC c                      Reset to Initial State
          ESC =                 (V)  Application Keypad Mode

          ESC >                 (V)  Numeric Keypad Mode

          ESC # 8               (V)  Fill Screen with E's

          ESC \                 (A)  String Terminator

          ESC ^                 (A)  Privacy Message String (Message

          ESC !                      Global Message String (Message

          ESC k                      A.k.a. Definition String

          ESC P                 (A)  Device Control String.  Outputs a
                                     string directly to the host
                                     terminal without interpretation.

          ESC _                 (A)  Application Program Command (not

          ESC ]                 (A)  Operating System Command (not

          Control-N             (A)  Lock Shift G1 (SO)

          Control-O             (A)  Lock Shift G0 (SI)

          ESC n                 (A)  Lock Shift G2

          ESC o                 (A)  Lock Shift G3

          ESC N                 (A)  Single Shift G2

          ESC O                 (A)  Single Shift G3

          ESC ( Pcs             (A)  Designate character set as G0

          ESC ) Pcs             (A)  Designate character set as G1

          ESC * Pcs             (A)  Designate character set as G2

          ESC + Pcs             (A)  Designate character set as G3

          ESC [ Pn ; Pn H            Direct Cursor Addressing

          ESC [ Pn ; Pn f            Direct Cursor Addressing

          ESC [ Pn J                 Erase in Display

                Pn = None or 0       From Cursor to End of Screen

                     1               From Beginning of Screen to

                     2               Entire Screen

          ESC [ Pn K                 Erase in Line

                Pn = None or 0       From Cursor to End of Line

                     1               From Beginning of Line to Cursor

                     2               Entire Line

          ESC [ Pn A                 Cursor Up

          ESC [ Pn B                 Cursor Down

          ESC [ Pn C                 Cursor Right

          ESC [ Pn D                 Cursor Left

          ESC [ Ps ;...; Ps m        Select Graphic Rendition

                Ps = None or 0       Default Rendition

                     1               Bold

                     2          (A)  Faint

                     3          (A)  Standout Mode (ANSI: Italicized)

                     4               Underlined

                     5               Blinking

                     7               Negative Image

                     22         (A)  Normal Intensity

                     23         (A)  Standout Mode off (ANSI:
                                     Italicized off)

                     24         (A)  Not Underlined

                     25         (A)  Not Blinking

                     27         (A)  Positive Image

          ESC [ Pn g                 Tab Clear

                Pn = None or 0       Clear Tab at Current Position

                     3               Clear All Tabs

          ESC [ Pn ; Pn r       (V)  Set Scrolling Region

          ESC [ Pn I            (A)  Horizontal Tab

          ESC [ Pn Z            (A)  Backward Tab

          ESC [ Pn L            (A)  Insert Line

          ESC [ Pn M            (A)  Delete Line

          ESC [ Pn @            (A)  Insert Character

          ESC [ Pn P            (A)  Delete Character

          ESC [ Ps ;...; Ps h        Set Mode

          ESC [ Ps ;...; Ps l        Reset Mode

                Ps = 4          (A)  Insert Mode

                     ?1         (V)  Application Cursor Keys

                     ?3         (V)  Change Terminal Width to 132

                     ?5         (V)  Visible Bell (On followed by Off)

                     ?6         (V)  Origin Mode

                     ?7         (V)  Wrap Mode

          ESC [ 5 i             (A)  Start relay to printer (ANSI
                                     Media Copy)

          ESC [ 4 i             (A)  Stop relay to printer (ANSI Media

          ESC [ 8 ; Ph ; Pw t        Resize the window to `Ph' lines
                                     and `Pw' columns (SunView

          ESC [ c                    Send VT100 Identification String

          ESC [ 6 n                  Send Cursor Position Report

          The following table describes all terminal capabilities that
          are recognized by screen and are not in the termcap(5)

          LP   (bool)  Terminal has vt100 style margins (`magic
                       margins'). Note that this capability is
                       obsolete because screen uses 'xn' instead.

          Z0   (str)   Change width to 132 columns.

          Z1   (str)   Change width to 80 columns.

          WS   (str)   Resize display. This capability has the desired
                       width and height as arguments. SunView(tm)
                       example: '\E[8;%d;%dt'.

          B8   (str)   Tell screen to look out for characters with 8th
                       bit set. If such a character is found screen
                       processes the specified string and than outputs
                       the character with the 8th bit stripped off.
                       Note that the string can contain any esc-
                       sequences known to screen, too. (Example:
                       Single Shift G2 = \EN.)

          OP   (bool)  Don't do a full vt100 style margin emulation.
                       Same as the -O option.

          NF   (bool)  Terminal doesn't need flow control. Send ^S and
                       ^Q direct to the application. Same as 'flow
                       off'. The opposite of this capability is 'xo'.

          G0   (bool)  Terminal can deal with ISO2022 font selection

          S0   (str)   Switch charset 'G0' to the specified charset.
                       Default is '\E(%d'.

          E0   (str)   Switch charset 'G0' back to standard charset.
                       Default is '\E(B'.

          C0   (str)   Use the string as a conversion table for font
                       '0'. See the 'ac' capability for more details.

          CS   (str)   Switch cursorkeys to application mode.

          CE   (str)   Switch cursorkeys back to normal mode.

          AN   (bool)  Turn on autonuke. See the 'autonuke' command
                       for more details.

          OL   (num)   Set the output buffer limit. See the
                       'obuflimit' command for more details.

          COLUMNS        Number of columns on the terminal (overrides
                         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.

          /local/etc/screenrc         screen initialization commands
          $HOME/.screenrc             Read in after
          /local/screens/S-<login>    Socket directories (default)
          /usr/tmp/screens/S-<login>  Alternate socket directories.
          <socket directory>/.termcap Written by the "termcap" output
          /tmp/screen-exchange        screen `interprocess
                                      communication 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.

          termcap(5), utmp(5), vi(1), captoinfo(1), tic(1)

          Originally created by Oliver Laumann, this latest version
          was produced by Wayne Davison, Juergen Weigert and Michael

          Copyright (C) 1993      Juergen Weigert
          (      Michael
          Schroeder (
          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
          PURPOSE.  See the GNU General Public License for more
          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.

          Ken Beal (,
          Rudolf Koenig (,
          Toerless Eckert (,
          Wayne Davison (,
          Patrick Wolfe (, kailand!pat),
          Bart Schaefer (,
          Nathan Glasser (,
          Larry W. Virden (,
          Howard Chu (,
          Tim MacKenzie (,
          Markku Jarvinen (mta@{cc,cs,ee},
          Marc Boucher (marc@CAM.ORG),
          Doug Siebert (,
          Ken Stillson (,
          Ian Frechett (frechett@spot.Colorado.EDU),
          Brian Koehmstedt (,
          Don Smith (,
          Frank van der Linden (,
          Martin Schweikert (,
          David Vrona (,
          E. Tye McQueen (,
          Matthew Green (,
          Christopher Williams (,
          Matt Mosley (,
          Gregory Neil Shapiro (gshapiro@wpi.WPI.EDU).

          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.

          +  `dm' (delete mode) and `xs' are not handled correctly
             (they are ignored). `xn' is treated as a magic-margin

          +  The GR set of ISO 2022 is not supported.

          +  There is no keyboard input translation to VT100

          +  It is not possible to change the environment variable
             $TERMCAP when reattaching under a different terminal

          +  The support of terminfo based systems is very limited.
             Adding extra capabilities to $TERMCAP may not have any

          +  Screen does not make use of hardware tabs.

          +  Screen must be installed as set-uid with owner root in
             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".

          +  Entries in "/etc/utmp" are not removed when screen 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.

          +  Screen may give a strange warning when your tty has no
             utmp entry.

          +  Send bugreports, fixes, enhancements, t-shirts, money,
             beer & pizza to