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 the 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 the user to move
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 the current window, view a list of the active
windows, turn output logging on and off, copy text between windows, view
the scrollback history, switch between windows, etc. When a program
terminates, screen kills the window that contained it. If this
window was in the foreground, the display switches to the previously
displayed 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 (see section Command Character) and all the key bindings (see section Key Binding) 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) 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 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 closed. 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 section Login.
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,
qterm, or just set term=mytermtype, 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 ? (see section Key Binding). Typing these two characters will display a list of the
available screen commands and their bindings. Each keystroke is
discussed in the section on keystrokes (see section Default Key Bindings).
Another section (see section Customizing Screen) 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. 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 `xn' capability in your termcap
(see section Termcap), or by using the `-L'
command-line option. screen needs this information to correctly
update the screen. You don't need to worry about this if your terminal
type starts with `vt', as screen assumes `xn' in that case.
If you are using a "true" auto-margin terminal (no `xn') 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).
See section Special Terminal Capabilities, for more information about telling
screen what kind of terminal you have.
ScreenScreen has the following command-line options:
screen must redraw parts of the display
in order to implement a function.
screen may try to restore its old window sizes when attaching to
resizeable terminals (those with `WS' in their descriptions, e.g.
suncmd or some varieties of xterm).
screen session
running elsewhere (see section Detach). `-d' has the same effect as
typing C-a d from the controlling terminal for the session.
`-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 log out from a remote terminal and transport the
session running there to your current terminal.
Note: It is a good idea to check the status of your sessions
with screen -list before using this option.
escape command
(see section Command Character).
defflow command (see section Flow Control).
defscrollback command (see section Copying).
interrupt argument to the defflow command (see section Flow Control). Its use is discouraged.
deflogin command (see section Login).
screen, but instead print a list of session
identification strings (usually of the form pid.tty.host;
see section Session Name). 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 why they died. Remove sessions with the `-wipe' option.
screen that your auto-margin terminal allows programs to
write to the last column of the last row of the screen without
scrolling. This can also be set in your `.screenrc' by specifying
`xn' in a termcap command (see section Termcap).
screen to ignore the $STY environment variable. When
this option is used, a new session will always be created, regardless of
whether screen is being called from within another screen
session or not.
termcap command (see section Termcap).
screen session. No other options (except
`-d' or `-D') may be specified, though the session name
(see section Session Name) may be needed to distinguish between multiple
detached screen sessions.
screen session. If
successful, all other command-line options are ignored. If no detached
session exists, start a new session using the specified options, just as
if `-R' had not been specified. This option is set by default if
screen is run as a login-shell.
screen
uses the value of the environment variable $SHELL, or
`/bin/sh' if it is not defined. This option is equivalent to the
shell command (see section Shell).
screen -list and screen -r commands. This option is
equivalent to the sessionname command (see section Session Name).
shellaka command
(see section Shell).
screen -ls, but remove destroyed
sessions instead of marking them as `dead'.
Screen
You can modify the default settings for screen to fit your tastes
either through a personal `.screenrc' file which contains commands
to be executed at startup, or on the fly using the colon command.
screen is invoked, it executes initialization commands from
the files `/local/etc/screenrc' and `.screenrc' in the user's
home directory. These defaults can be overridden in the following ways:
For the global screenrc file screen searches for the environment
variable $SYSSCREENRC. The user specific screenrc file is
searched for in $ISCREENRC, then $SCREENRC, then
`$HOME/.iscreenrc' and finally defaults to
`$HOME/.screenrc'. The command line option `-c'
specifies which file to use (see section Invoking Screen. Commands in these
files are used to set options, bind commands to keys, and to
automatically establish one or more extra 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 ${VAR}. Note that this causes incompatibilities
with previous screen versions, as now the '$'-sign has to be
protected with '\' if no variable substitution is intended.
(C-a :)
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,
as of version 3.3. Change default settings with commands starting with
`def'. You might think of this as the ex command mode of
screen, with copy as its vi command mode
(see section Copy and Paste).
A command in screen can either be bound to a key, invoked from a
screenrc file, or called from the colon prompt
(see section Customizing Screen). As of version 3.3, all commands can be bound
to keys, although some may be less useful than others.
In this manual, a command definition looks like this:
An argument in square brackets (`[]') is optional. Many commands take an argument of `on' or `off', which is indicated as state in the definition.
As mentioned previously, each keyboard 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, both C-a c and C-a C-c can be used to create a window.
The following table shows the default key bindings:
escape command.
See section Command Character.
screen from this terminal. See section Detach.
screen. See section Suspend.
screen. See section Quit.
acladd username
acldel username
activity message
aka [windowalias]
allpartial state
autodetach state
autonuke state
bell message
bind key [command [args]]
bind command.
break [duration]
bufferfile [exchange-file]
chdir [directory]
clear
colon
screen command. See section Colon.
console [state]
copy
copy_reg [key]
crlf state
defautonuke state
defflow fstate
deflogin state
defmode mode
defmonitor state
defobuflimit limit
defscrollback num
defwrap state
detach
screen from the terminal. See section Detach.
dumptermcap
echo [-n] message
escape xy
meta characters. See section Command Character.
exec [[fdpat] command [args ...]]
flow [fstate]
hardcopy
hardcopy_append state
hardcopydir directory
hardstatus [state]
height [lines]
help
history
info
ins_reg [key]
kill
lastmsg
license
lockscreen
log [state]
logdir directory
login [state]
markkeys string
meta
monitor [state]
msgminwait sec
msgwait sec
multiuser state
nethack state
nethack-like error messages. See section Nethack.
next
obuflimit [limit]
other
partial state
password [crypted_pw]
paste
pow_break
pow_detach
pow_detach_msg message
pow_detach. See section Power Detach.
prev
process [key]
screen. See section Registers.
quit
readbuf
redisplay
register key string
removebuf
reset
screen [opts] [n] [cmd [args]]
scrollback num
select [n]
sessionname [name]
setenv var string
shell command
shellaka a.k.a.
silence [state|seconds]
silencewait seconds
sleep num
slowpaste msec
startup_message state
suspend
term term
$TERM for new windows. See section Term.
termcap term terminal-tweaks [window-tweaks]
termcap command.
terminfo term terminal-tweaks [window-tweaks]
termcap command.
time
unsetenv var
vbell [state]
vbell_msg message
vbellwait sec
version
screen version. See section Version.
width [num]
windows
wrap [state]
writebuf
xoff
xon
This section describes the commands for creating a new window for running programs. When a new window is created, the first available number from the range 0...9 is assigned to it. There can be no more than 10 windows active at any one time.
(none)
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 interactively.
(C-a c, C-a C-c)
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 lines
# 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
a.k.a. `foobar' in window #2). If you do not include any
screen commands in your `.screenrc' file, then screen
defaults to creating a single shell window, number zero. When the
initialization is completed, screen switches to the last window
specified in your .screenrc file or, if none, it opens default window
#0.
(none)
Set the environment variable var to value string.
The environment is inherited by all subsequently forked shells.
(none)
Unset an environment variable.
(none)
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.
(none)
Set the a.k.a. for all shells created during startup or by the C-a C-c
command. See section Also Known As (A.K.A.s), for details about what a.k.a.'s are.
(none)
In each window screen opens, it sets the $TERM
variable to `screen' by default, unless no description for
`screen' is installed in the local termcap or terminfo data base.
In that case it pretends that the terminal emulator is `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.
This section describes the commands for switching between windows in an
screen session. The windows are numbered from 0 to 9, and are created
in that order by default (see section New Window).
(C-a SPC, C-a n, C-a C-n)
Switch to the next window. This command can be used repeatedly to
cycle through the list of windows. (On some terminals, C-SPC
generates a NUL character, so you must release the control key before
pressing space.)
(C-a p, C-a C-p)
Switch to the previous window (the opposite of C-a n).
(C-a C-a)
Switch to the last window displayed. Note that this command
defaults to the command character typed twice, unless overridden; for
instance, if you use the option `-e]x', this command becomes
]], not ]C-a (see section Command Character). On the other
hand, if you use the option `-e"', this command remains `
C-a, since " is bound to meta.
(C-a n, C-a ', C-a ")
Switch to the window with the number n.
If no window number is specified, you get prompted for an
identifier. This can be an a.k.a. or a number.
Perhaps the most useful feature of screen is the way it allows
the user to move a session between terminals, by detaching and
reattaching. This also makes life easier for modem users who have to
deal with unexpected loss of carrier.
(none)
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.
(C-a d, C-a C-d)
Detach the screen session (disconnect it from the terminal and
put it into the background). A detached screen can be resumed by
invoking screen with the -r option. (see section Invoking Screen)
Command: password [crypted_pw]
(none)
Present a crypted password in your `.screenrc' file and screen will
ask for it, whenever someone attempts to resume a detached session. This
is useful, if you have privileged programs running under screen
and you want to protect your session from reattach attempts by users
that managed to assume your uid. (I.e. any superuser.) If no crypted
password is specified, screen prompts twice a password and places its
encryption in the copybuffer. Default is `none', which disables
password checking.
(C-a D)
Mainly the same as detach, but also sends a HANGUP signal
to the parent process of screen.
Caution: This will result in a
logout if screen was started from your login shell.
Command: pow_detach_msg message
(none)
The message specified here is output whenever a power detach is
performed. It may be used as a replacement for a logout message or to reset
baud rate, etc.
(C-a x, C-a C-x)
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.
These commands allow other users to gain access to one single screen
session. When attaching to a multiuser screen the sessionname is
specified as username/sessionname.
(none)
Switch between single-user and multi-user mode. Standard screen operation is
single-user. In multi-user mode the commands acladd and acldel
can be used to enable (and disable) other users accessing this screen.
(none)
Enable a user to access this screen session. Multi-user mode only.
(none)
Remove a user from screens access control list. Multi-user mode only.
(none)
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 variable still reflects the old name. This may result in
confusion. The default is constructed from the tty and host names.
(C-a z, C-a C-z)
Suspend screen. The windows are in the detached state while
screen is suspended. This feature relies on the parent shell
being able to do job control.
(C-a C-\)
Kill all windows and terminate screen. Note that on vt100-style
terminals the keys C-4 and C-\ are identical. So 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
(see section Key Binding).
These commands control the way screen treats individual windows
in a session. See section Virtual Terminal, for comands to control the
terminal emulation itself.
You can customize each window's name in the window display (viewed with
the windows command (see section Windows) by setting it with
one of the a.k.a. 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
shellaka command (see section Shell). You can specify the name you
want for a window with the `-t' option to the screen command
when the window is created (see section Screen Command). To change the name after
the window has been created you can use the AKA-string escape-sequence
(ESC k name ESC \) and the aka 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 predefined names to keys with the
aka command to set things quickly without prompting.
(C-a A)
Set the name of the current window to windowalias. If no name is
specified, screen prompts for one.
screen has a shell-specific heuristic that is enabled by
setting the window's name to search|name and arranging to have a
null aka 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 specified 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
aka 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 a.k.a. Once this is set
up, screen will use the aka 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 `!',
`%', 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 more accurate AKA's when using job control or
history recall commands.
set prompt='<ESC>[0000m<ESC>k<ESC>\% '
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.
Tcsh handles escape codes in the prompt more intelligently, so you can specify your prompt like this:
set prompt="%{\ek\e\\%}\% "
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 v1.04).
screen -t top 2 nice top
Adding this line to your .screenrc would start a niced version of the
top command in window 2 name `top' rather than `nice'.
shellaka '> |csh' screen 1
This file would start a shell using the given shellaka. The a.k.a. specified is an auto-aka 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-aka name of
`root:'. For this auto-aka 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 aka bind E aka "" bind u aka (unknown)
The first binding doesn't have any arguments, so it would prompt you for an a.k.a. when you type C-a o. The second binding would clear an auto-aka's current setting (C-a E). The third binding would set the current window's a.k.a. to `(unknown)' (C-a u).
(none)
Sets whether a clear screen sequence should nuke all the output
that has not been written to the terminal. See section Obuflimit.
(none)
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 terminal type dependant setting.
(none)
Grabs or ungrabs the machines console output to a window. When the argument
is ommitted the current state is displayed.
(C-a k, C-a C-k)
Kill the current window.
If there is an exec command running (see section Exec) then it is killed.
Otherwise the process (e.g. 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.
Caution: emacs users may find themselves killing their
emacs session when trying to delete the current line. For this
reason, it is probably wise to use a different command character
(see section Command Character) or rebind kill to another key
sequence, such as C-a K (see section Key Binding).
(none)
Same as the login command except that the default setting for new
windows is changed. This defaults to `on' unless otherwise specified at
compile time (see section Installation).
(C-a L)
Adds or removes the entry in `/etc/utmp' for the current window.
This controls whether or not the window is logged in. In addition
to this toggle, it is convenient to have "log in" and "log out"
keys. For instance, bind I login on and bind O
login off will map these keys to be C-a I and C-a O
(see section Key Binding).
(none)
The mode of each newly allocated pseudo-tty is set to mode.
mode is an octal number as used by chmod(1). Defaults to 0622 for
windows which are logged in, 0600 for others (e.g. when -ln was
specified for creation. see section Screen Command).
(none)
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 redefined 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).
(none)
Same as the monitor command except that the default setting for
new windows is changed. Initial setting is `off'.
(C-a M)
Toggles monitoring of the current window. When monitoring is turned on
and the affected window is switched into the background, the activity
notification message will be displayed in the status line at the first
sign of output, and the window will also be marked with an `@' in
the window-status display (see section Windows). Monitoring defaults to
`off' for all windows.
(none)
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.
(none)
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 terminal
type dependant limit.
(C-a w, C-a C-w)
Uses the message line to display a list of all the windows. Each
window is listed by number with the name of the program running in the
window (or its a.k.a.); 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 `$' (see section Login); 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 `@' (see section Monitoring); a window which has output logging turned
on is marked with `(L)'.
Each window in a screen session emulates a VT100 terminal, with
some extra functions added. The commands described here modify the
terminal emulation.
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 Line)
ESC ! Global Message String (Message Line)
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 used)
ESC ] (A) Operating System Command (not used)
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 Cursor
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 columns
?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 Copy)
ESC [ 8 ; Ph ; Pw t Resize the window to `Ph' lines and
`Pw' columns (SunView special)
ESC [ c Send VT100 Identification String
ESC [ 6 n Send Cursor Position Report
(none)
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 "").
(C-a C-g)
Sets or toggles the visual bell setting for the current window. If your
terminal does not support a visual bell, the visual bell message is
displayed in the status line. See section 'Visual Bell' in The Termcap Manual, for more information on visual bells. The equivalent
terminfo capability is flash.
(none)
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, Wuff!!'.
(none)
Define a delay in seconds after each display of screen 's visual
bell message. The default is 1 second.
(C-a C)
Clears the screen and saves its contents to the scrollback buffer.
(none)
Set the display height to a specified number of lines. When no
argument is given it toggles between 24 and 42 lines display.
(C-a i, C-a C-i)
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
time.
(none)
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.
(none)
Defines whether the display should be refreshed (as with
redisplay) 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 course.
(C-a l, C-a C-l)
Redisplay the current window. Needed to get a full redisplay in
partial redraw mode.
(C-a r, C-a C-r)
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'.
(none)
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".
(C-a Z)
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.
(C-a W)
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 (see section Termcap), for more information.
For those confined to a hardware terminal, these commands provide a cut and paste facility more powerful than those provided by most windowing systems.
(C-a [, C-a C-[, C-a ESC)
Enter copy/scrollback mode. This allows you to copy text from the
current window and its history into the paste buffer. In this mode a
vi-like full screen editor is active, with controls as
outlined below.
(none)
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 only `LF' is used.
crlf is off by default.
(none)
Same as the scrollback command except that the default setting
for new windows is changed. Defaults to 100.
(none)
Set the size of the scrollback buffer for new windows to num
lines. The default scrollback is 100 lines. Use C-a i to view
the current setting.
(none)
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 command markkeys
h=^B:l=^F:$=^E would set some keys to be more familiar to emacs
users.
h, j, k, l move the cursor line by line or column by column.
0, ^ and $ move to the leftmost column or 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 - move the cursor to the leftmost column of the next or previous line.
G moves to the specified absolute line (default: end of buffer). | 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 screenfull).
C-b and C-f move the cursor up/down a full screen.
g moves to the beginning of the buffer.
% jumps to the specified percentage of the buffer.
Note that Emacs-style movement keys can be specified by a .screenrc
command. (markkeys "h=^B:l=^F:$=^E") There is no simple method for
a full emacs-style keymap, however, 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 can be used to mark one whole line or to mark from start of line.
W marks exactly one word.
Any command in copy mode can be prefixed with a 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 here from in
vi. Vi does not allow 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, or lines separated by a
single space. Note that you can prepend the newline character with
a carriage return character, by issuing a set crlf on.
v is for all the vi users who use :set numbers - it
toggles the left margin between column 9 and 1.
a before the final space key turns on append mode. Thus the contents of the pastebuffer will not be overwritten, but appended to.
A turns on 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. See section Screen-Exchange.
This example demonstrates how to dump the
whole scrollback buffer to that file:
C-a [ g SPACE G $ >.
C-g gives information about the current line and column.
@ does nothing. Absolutely nothing. Does not even exit copy mode.
(C-a ], C-a C-])
Write the contents of the paste buffer to the stdin stream of the
current window. The paste buffer can be filled with the copy,
history and readbuf commands.
(none)
Define the speed text is inserted by the paste command.
For each 80 characters (IOSIZE) pasted, screen will pause for
msec milliseconds to allow the application to process the
input. Use slowpaste if your underlying system chokes on large
pastes (i.e. a VAX).
(none)
Store the current copybuffer contents in a register referenced by key.
If the name is omitted you will be prompted to press the key.
(none)
Paste contents of register key into the current window's input
stream.
(none)
Stuff the contents of the specified register into the screen
input queue. If no argument is given you are prompted for a
register name. This command can be used to bind multiple actions
to a single key.
(none)
Save the specified string to the register key.
Command: bufferfile [exchange-file]
(none)
Change the filename used for reading and writing with the copybuffer.
If the exchange-file parameter is omitted, screen reverts
to the default of `/tmp/screen-exchange'. 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 <)
Reads the contents of the current screen-exchange file into the copy buffer.
(C-a =)
Unlinks the screen-exchange file.
(C-a >)
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. See also
C-a ESC (see section Copying).
(C-a {)
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 provides a primitive way of
recalling "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).
(none)
Run a unix subprocess (specified by an executable path newcommand and
its optional arguments) 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 symbol
(`|') 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 `doc/fdpat.ps' 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.
Examples:
!/bin/sh
exec /bin/sh
exec ... /bin/sh
!!stty 19200
exec!stty 19200
exec !.. stty 19200
|less
exec !..| less
screen would not expect without the `|')
when its stdin is not a tty.
!:sed -n s/.*Error.*/\007/p
You may disagree with some of the default bindings (I know I do). The
bind command allows you to redefine them to suit your
preferences.
bind command
(none)
Bind a command to a key. 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 (see section Command Index).
By default, most suitable commands are bound to one or more keys
(see section Default Key Bindings; for instance, 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.
bind command
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 ESC to the command that creates an non-login window with a.k.a. `root' in slot #9, with a super-user shell and a scrollbackbuffer of 1000 lines.
(none)
Set the command character to x and the character generating a
literal command character to y (just like with 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', but `"' is recommended by
one of the authors.
(C-a a)
Send the command character (C-a) to the process in the current
window. The keystroke for this command is the second parameter to the
`-e' command line switch (see section Invoking Screen), or the
escape .screenrc directive.
(C-a ?)
Displays a help screen showing you all the key bindings. The first
pages list all the internal commands followed by their 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 exit the help display and begin a command.
See section Default Key Bindings.
screen can trap flow control characters or pass them to the
program, as you see fit. This is useful when your terminal wants to use
XON/XOFF flow control and you are running a program which wants to use
^S/^Q for other purposes (i.e. emacs).
screen flow control settingsemacs 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 command. By default the
windows are set to automatic flow-switching. It can then be toggled
between the three states 'fixed on', 'fixed off' and 'automatic'
interactively with the flow command bound to C-a f.
The automatic flow-switching mode deals with flow control using the
TIOCPKT mode (like rlogin does). If the tty driver does not
support TIOCPKT, screen tries to determine 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 the
`interrupt' parameter only takes effect when flow-control is
enabled. If your program's output is interrupted by mistake, 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.
(none)
Same as the flow command except that the default setting for new
windows is changed. Initial setting is `auto'.
Specifying flow auto
interrupt has the same effect as the command-line options `-fa'
and `-i'.
(C-a f, C-a C-f)
Sets the flow-control mode for this window to fstate, which can be
`on', `off' or `auto'.
Without parameters it cycles the current window's
flow-control setting. Default is set by `defflow'.
(C-a q, C-a C-q)
Send a ^Q (ASCII XON) to the program in the current window. Redundant
if flow control is set to `off' or `auto'.
(C-a s, C-a C-s)
Send a ^S (ASCII XOFF) to the program in the current window.
screen demands the most out of your terminal so that it can
perform its VT100 emulation most efficiently. These functions provide
means for tweaking the termcap entries for both your physical terminal
and the one simulated by screen.
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 works:
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.
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 command, or by defining the variable
$SCREENCAP prior to startup. When the 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 command if the system
uses the terminfo database rather than termcap. On such machines the
$TERMCAP variable has no effect and you must use the
dumptermcap command (see section Write out the window's termcap entry) and the tic
program to generate terminfo entries for screen windows.
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. You can force screen to
include all capabilities in $TERMCAP with the `-a'
command-line option (see section Invoking Screen).
(C-a .)
Write the termcap entry for the virtual terminal optimized for the
currently active window to the file `.termcap' in the user's
`$HOME/.screen' directory (or wherever screen stores its
sockets. see section Files Referenced). 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.
termcap commandCommand: terminfo term terminal-tweaks [window-tweaks]
(none)
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 uses the terminfo database rather than
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 section Virtual Terminal).
termcap xterm* xn: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 (xn), but they don't really have a status line (no 'hs' --
append `@' to turn entries off). Note that we assume `xn' for
all terminal names that start with `vt', but only if you don't
specify a termcap command for that terminal.
termcap vt* xn termcap vt102|vt220 Z0=\E[?3h:Z1=\E[?3l
Specifies the firm-margined `xn' 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 deletion).
If you would like to fully specify each window's termcap entry, you
should instead set the $SCREENCAP variable prior to running
screen. See section Virtual Terminal, for the details of the
screen terminal emulation. See section 'Termcap' in The Termcap Manual, for more information on termcap definitions.
screen and are not in the termcap manual
(see section 'Termcap' in The Termcap Manual).
screen now uses `xn'
instead.
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.)
flow off. The opposite of this
capability is `xo'.
screen displays informational messages and other diagnostics in a
message line at the bottom of the screen. If your terminal has a
status line defined in its termcap, screen will use this for displaying
its messages, otherwise the last line of the 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.
echo "<ESC>^Hello world from window $WINDOW<ESC>\"
where `<ESC>' is ASCII ESC and `^' is a literal caret or up-arrow.
(none)
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'.
(C-a m, C-a C-m)
Repeat the last message displayed in the message line. Useful if you're
typing when a message appears, because (unless your terminal has a
hardware status line) the message goes away when you press a key.
(none)
Defines the time screen delays a new message when another is
currently displayed. Defaults to 1 second.
(none)
Defines the time a message is displayed, if screen is not
disturbed by other activity. Defaults to 5 seconds.
This section describes the commands for keeping a record of your session.
(C-a h, C-a C-h)
Writes out the current display contents to the 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, as determined by the hardcopy_append command.
Command: hardcopy_append state
(none)
If set to `on', screen will append to the
`hardcopy.n' files created by the command hardcopy;
otherwise, these files are overwritten each time.
(none)
Defines a directory where hardcopy files will be placed.
If unset hardcopys are dumped in screens current working
directory.
(C-a H)
Begins/ends logging of the current window to the file
`screenlog.n' in the window's default directory, where
n is the number of the current window. If no parameter is given,
the logging state is toggled. The session log is
appended to the previous contents of the file if it already exists. The
current contents and the contents of the scrollback history are not
included in the session log. Default is `off'.
(none)
Defines a directory where logfiles will be placed. If unset logfiles
are written in screens current working directory.
This section describes commands which are only useful in the `.screenrc' file, for use at startup.
(none)
The echo command may be used to annoy screen users with a
'message of the day'. Typically installed in a global screenrc. See also
sleep. Echo is also useful for online checking of environment
variables.
(none)
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.
(none)
Select whether you want to see the copyright notice during startup.
Default is `on', as you probably noticed.
The commands described here do not fit well under any of the other categories.
(none)
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.
(none)
Reopen the window's terminal line and send a break condition.
(none)
Display the disclaimer page. This is done whenever screen is
started without options, which should be often enough.
(none)
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 (see section Installation). The default setting is then
determined by the presence of the environment variable
$NETHACKOPTIONS.
(none)
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.
(none)
Define the time that all windows monitored for silence should wait
before displaying a message. Default is 30 seconds.
(C-a t, C-a C-t)
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 (see section Info).
(C-a v, C-a C-v)
Display the version and modification date in the message line.
COLUMNS
HOME
ISCREENRC
LINES
LOCKPRG
NETHACKOPTIONS
nethack option.
PATH
SCREENCAP
TERMCAP value.
SCREENDIR
SCREENRC
SHELL
STY
screen is invoked, and the environment variable
STY is set, then it creates only a window in the running screen
session rather than starting a new session.
SYSSCREENRC
TERM
TERMCAP
$SYSSCREENRC'
screen initialization commands
$ISCREENRC'
$SCREENRC'
$HOME/.iscreenrc'
$HOME/.screenrc'
$ISCREENDIR/S-login'
$SCREENDIR/S-login'
dumptermcap command
screen interprocess communication buffer
$LOCKPRG'
Authors
=======
Originally created by Oliver Laumann, this latest version was produced by Wayne Davison, Juergen Weigert and Michael Schroeder.
Contributors
============
Ken Beal (kbeal@amber.ssd.csd.harris.com),
Rudolf Koenig (rfkoenig@informatik.uni-erlangen.de),
Toerless Eckert (eckert@informatik.uni-erlangen.de),
Wayne Davison (davison@borland.com),
Patrick Wolfe (pat@kai.com, kailand!pat),
Bart Schaefer (schaefer@cse.ogi.edu),
Nathan Glasser (nathan@brokaw.lcs.mit.edu),
Larry W. Virden (lvirden@cas.org),
Howard Chu (hyc@hanauma.jpl.nasa.gov),
Tim MacKenzie (tym@dibbler.cs.monash.edu.au),
Markku Jarvinen (mta@{cc,cs,ee}.tut.fi),
Marc Boucher (marc@CAM.ORG),
Doug Siebert (dsiebert@isca.uiowa.edu),
Ken Stillson (stillson@tsfsrv.mitre.org),
Ian Frechett (frechett@spot.Colorado.EDU),
Brian Koehmstedt (bpk@gnu.ai.mit.edu),
Don Smith (djs6015@ultb.isc.rit.edu),
Frank van der Linden (vdlinden@fwi.uva.nl),
Martin Schweikert (schweik@cpp.ob.open.de),
David Vrona (dave@sashimi.lcu.com),
E. Tye McQueen (tye%spillman.UUCP@uunet.uu.net),
Matthew Green (phone@coombs.anu.edu.au),
Christopher Williams (cgw@unt.edu),
Matt Mosley (mattm@access.digex.net),
Gregory Neil Shapiro (gshapiro@wpi.WPI.EDU),
Jason Merrill (jason@jarthur.Claremont.EDU).
Version
=======
This is version 3.3. 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.
Just like any other significant piece of software, screen has a
few bugs and missing features. Please send in a bug report if you have
found a bug not mentioned here.
$TERMCAP
when reattaching under a different terminal type.
$TERMCAP may not have any effects.
screen does not make use of hardware tabs.
screen must be installed setuid root in order to be able to
correctly change the owner of the tty device file for each window.
Special permission may also be required to write the file
`/etc/utmp'.
screen is killed
with SIGKILL. This will cause some programs (like "w" or "rwho") to
advertise that a user is logged on who really isn't.
screen may give a strange warning when your tty has no utmp
entry.
If you find a bug in Screen, please send electronic mail to
`screen@uni-erlangen.de', and also to
`bug-gnu-utils@prep.ai.mit.edu'. Include the version number
of Screen which you are using. Also include in your message the
hardware and operating system, the compiler used to compile, a
description of the bug behavior, and the conditions that triggered the
bug. Please recompile screen with the `-DDEBUG -DTMPTEST' options
enabled, reproduce the bug, and have a look at the debug output written to
the directory `/tmp/debug'. If necessary quote suspect passages from the
debug output and show the contents of your `config.h' if it matters.
Since screen uses pseudo-ttys, the select system call, and
UNIX-domain sockets, it will not run under a system that does not
include these features of 4.2 and 4.3 BSD UNIX.
The socket directory defaults either to `$HOME/.screen' or
preferably to `/local/screens'. If screen is installed
setuid root, then the administrator should compile screen with an
adequate (not NFS mounted) SOCKDIR. If screen is not
running setuid-root, the user can specify any mode 777 directory in the
environment variable $SCREENDIR.
To compile and install screen:
The screen package comes with a GNU Autoconf configuration
script. Before you compile the package run
sh ./configure
This will create a `config.h' and `Makefile' for your machine.
If configure fails for some reason, then look at the examples and
comments found in the `Makefile.in' and `config.h.in' templates.
Rename `config.status' to `config.status.machine' when
you want to keep configuration data for multiple architectures. Runing
sh ./config.status.machine recreates your configuration
significantly faster than rerunning configure.
Read through the "User Configuration" section of `config.h', and verify
that it suits your needs.
A comment near the top of this section explains why it's best to
install screen setuid to root.
Check for the place for the global `screenrc'-file and for the socket
directory.
Check the compiler used in `Makefile', the prefix path where to install
screen. Then run
make
If make fails to produce one of the files `term.h', `comm.h'
or `tty.c', then use filename.x.dist instead.
For additional information about installation of screen refer to the
file `INSTALLATION', coming with this package.