SCREEN(1) SCREEN(1)
NAME
screen - screen manager with VT100/ANSI terminal emulation
SYNOPSIS
screen [ -options ] [ cmd [ args ] ]
screen -r [ [pid.]tty[.host] ]
DESCRIPTION
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, sev-
eral control functions from the ANSI X3.64 (ISO 6429) and
ISO 2022 standards (e.g. insert/delete line and support
for multiple character sets). There is a scrollback his-
tory buffer for each virtual terminal and a copy-and-paste
mechanism that allows moving text regions between windows.
The name of this program was changed to iScreen to be able
to distinguish it from Oliver Laumann's original screen
program. Despite that fact, this manual will continue to
use the name screen. This is, because often the binary is
installed as 'screen'.
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 nor-
mally would. Then, at any time, you can create new (full-
screen) windows with other programs in them (including
more shells), kill existing windows, view a list of the
current 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 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. Simi-
larly, you can create a new window with a custom command
in it by first binding the command to a keystroke (in your
.screenrc file) and then using it just like the "C-a c"
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SCREEN(1) SCREEN(1)
command. In addition, new windows can be created by run-
ning 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 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 terminals own record is removed from the
utmp file. See also "C-a L".
GETTING STARTED
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 or stty, 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 "COMMAND KEYS". 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 cir-
cumstances. The next best thing is an auto-margin termi-
nal that allows the last position on the screen to be
updated without scrolling the screen (such as a vt100).
This also allows the entire screen to be updated. Lastly,
if all you've got is a "true" auto-margin terminal 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 short-
ened by using a terminal with insert-character capability.
If your terminal is of the second type (firm-margined
`am'), you will want to let screen know about this, since
a normal termcap doesn't distinguish this type of auto-
matic margins from a "true" `am' terminal. You do this by
specifying the `LP' capability in your termcap (see the
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SCREEN(1) SCREEN(1)
"termcap" .screenrc command), or by using the -L command-
line option. Screen needs this information to correctly
update the screen.
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).
COMMAND KEYS
As mentioned, each screen command consists of a "C-a" fol-
lowed by one other character. For your convenience, all
commands that are bound to lower-case letters are also
bound to their control character counterparts (with the
exception of "C-a a"; see below), thus, "C-a c" as well as
"C-a C-c" can be used to create a window.
The following keystroke commands are available:
C-a 0 - C-a 9 (select0 - select9)
Switch to the window with the number 0 through 9.
When a new window is established, the first avail-
able number from the range 0..9 is assigned to this
window. Thus, the first window can be activated by
"C-a 0" (there can be no more than 10 windows pre-
sent at any one time).
C-a C-a (other)
Switch to the window displayed previously. Note
that this function defaults to the command charac-
ter typed twice, unless overridden; for instance,
if you use the option "-e]x", this function becomes
"]]", not "]C-a".
C-a a
Send the command character (C-a) to the processes
in the current window.
C-a A (aka)
Allow the user to enter an a.k.a (also-known-as).
for the current window.
C-a c or C-a C-c (shell)
Create a new window with a shell and switch to that
window.
C-a C (clear)
Clear the screen (saves image to scrollback
buffer).
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SCREEN(1) SCREEN(1)
C-a d or C-a C-d (detach)
Detach screen (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 also section "COMMAND-LINE OPTIONS".)
C-a D (pow_detach)
Power detach. Mainly the same as above, 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.
C-a f or C-a C-f (flow)
Cycles the current window's flow-control setting
from "automatic" to "on" to "off", see the section
titled FLOW-CONTROL for details.
C-a C-g (vbell)
Toggles screen's visual bell mode. If your terminal
does not support a visual bell, a `vbell-message'
is displayed in the status line.
C-a h or C-a C-h (hardcopy)
Write a hardcopy of the current window to the file
"hardcopy.n" in the window's default directory,
where n is the number of the current window.
C-a H (log)
Begins/ends logging of the current window to the
file "screenlog.n" in the window's default direc-
tory, where n is the number of the current window.
The session log is appended to the previous con-
tents of the file if it already exists. The cur-
rent contents and the contents of the scrollback
history are not included in the session log.
C-a i or C-a C-i (info)
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 "C-a t".
C-a k or C-a C-k (kill)
Kill the current window and switch to the previ-
ously displayed window. Note: Emacs users should
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SCREEN(1) SCREEN(1)
keep this command in mind, when killing a line. It
is recommended not to use "C-a" as the screen
escape key or that kill is rebound to "C-a K".
C-a l or C-a C-l (redisplay)
Redisplay the current window.
C-a L (login)
Adds or removes the entry in /etc/utmp file for the
current window. This controls if the window is
`logged in'. See also above. Additionally to that
toggle, it is convenient having a `log in' and a
`log out' key. E.g. `bind I set login on' and `bind
O set login off' will map these keys to be C-a I
and C-a O.
C-a m or C-a C-m (lastmsg)
Repeat the last message displayed in the message
line. Useful if you're typing when a message
appears, because (unless your terminal has a status
line) the message goes away when you press a key.
C-a M (monitor)
Toggles monitoring of the current window. When
monitoring is turned on and the 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 windows.
C-a space or C-a n or C-a C-n (next)
Switch to the next window. This function can be
used repeatedly to cycle through the list of win-
dows. (Some terminals require you to release the
control key before pressing space.)
C-a p or C-a C-p (prev)
Switch to the previous window (the opposite of C-a
n).
C-a q or C-a C-q (xon)
Send a control-q to the program in the current win-
dow.
C-a r or C-a C-r (wrap)
Toggle the current window's line-wrap setting (turn
the current window's automatic margins on and off).
C-a s or C-a C-s (xoff)
Send a control-s to the program in the current win-
dow.
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C-a t or C-a C-t (time)
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 "C-a i".
C-a v or C-a C-v (version)
Display the version and compilation date.
C-a w or C-a C-w (windows)
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 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 `$'; 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 log-
ging turned on is marked with `(L)'.
C-a W (width)
Toggle the window width between 80 and 132 columns.
As this command became a toggle, "C-a N" is no
longer supported. This requires a capable terminal
and the termcap entries "Z0" and "Z1". See the
"termcap" command in section "CUSTOMIZATION" for
more information.
C-a x or C-a C-x (lock)
Call a screenlock program (/local/bin/lck or
/usr/bin/lock or a builtin, if no other is avail-
able). 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 $LOCKPRG
(which must be set in the shell from which screen
is started) and is executed with the user's uid and
gid.
C-a z or C-a C-z (suspend)
Suspend screen. The windows are in the `detached'
state, while screen is suspended.
C-a Z (reset)
Reset the virtual terminal to its "power-on" val-
ues.
C-a . (termcap)
Write the termcap entry for the virtual terminal of
the currently active window to the file ".termcap"
in the user's "$HOME/.screen" directory (or
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SCREEN(1) SCREEN(1)
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.
C-a ? (help)
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 charac-
ters are ignored, except for the command character,
which will exit the help display and begin a com-
mand.
C-a C-\ (quit)
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 write C-a C-4 when
selecting window no. 4. Use the empty bind command
(as in "bind '^'") to remove a key binding.
C-a : (colon)
Allows you to enter ".screenrc" command lines as
well as names of key-bound-functions. Useful for
on-the-fly modification of key bindings, specific
window creation and changing settings. Settings of
the current window can be changed by prepending the
command (if appropriate) with the keyword "set".
If you consider this as the `Ex command mode' of
screen, you may regard "C-a esc" as its `Vi command
mode'.
C-a [ or C-a C-[ or C-a esc (copy)
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:
Movement keys:
h, j, k, l move the cursor line by line or column
by column.
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 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
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specified amount of lines while preserving the cur-
sor position. (Default: half screenfull).
C-b and C-f scroll the display up/down a full
screen.
g moves to the beginning of the buffer, whereas
% jumps to the specified percentage.
Note: 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.
Marking:
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 respec-
tively.
Y and y can be 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 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.
Specials:
There are however some keys that act differently
here and in vi. Vi does not allow to yank rectan-
gular blocks of text, but screen does. Press
c or C to set the left or right margin respec-
tively. If no repeat count is given, both default
to the current cursor position. Try this on a
rather full text screen as an example: "C-A [ S-M
20 l SPACE c 10 l 5 j S-C SPACE".
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 "set
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 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 file: "C-A [ g
SPACE G $ >".
? gives information about the current line and col-
umn.
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SCREEN(1) SCREEN(1)
C-a ] or C-a C-] (paste)
Paste. Write the contents of the paste buffer to
the stdin queue of the current window.
C-a { (history)
Usually users work with a shell that allows easy
access to previous commands. E.g. csh has the com-
mand "!!" 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).
C-a > (write_buffer)
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".
C-a < (read_buffer)
Reads the screen-exchange file into the paste-
buffer. See also "C-a ]".
C-a = (kill_buffer)
Removes the exchange file used by "C-a <" and "C-a
>".
COMMAND-LINE OPTIONS
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 func-
tion.
-A Adapt the sizes of all windows to the size of the
display. By default, screen may try to restore its
old window sizes.
-c file
override the default configuration file from
"$HOME/.screenrc" to file.
-d|-D [pid.tty.host]
does not start screen, but detach the elsewhere run-
ning 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
31 January 1992 9
SCREEN(1) SCREEN(1)
combination "screen -D -r" can be used to `transport'
the elsewhere running session to this terminal and
logout there. Note: It is a good idea to have the
status of your sessions checked by means of "screen
-list".
-e xy
specifies the command character to be x and the char-
acter generating a literal command character to y
(when typed after the command character). The
default is "C-a" and `a', which can be specified as
"-e^Aa". See the "escape" .screenrc command for more
details.
-f, -fn, and -fa
turns flow-control on, off, or "automatic switching
mode". This can also be defined through the "flow"
.screenrc command.
-h num
Specifies the history scrollback buffer to be num
lines high.
-i will cause the interrupt key (usually C-c) to inter-
rupt the display immediately when flow-control is on.
See the "flow" .screenrc command for details.
-l and -ln
turns login mode on or off (for /etc/utmp updating).
This can also be defined through the "login"
.screenrc command.
-ls and -list
does not start screen, but prints a list of
pid.tty.host strings identifying your screen ses-
sions. Sessions marked `detached' can be resumed
with "screen -r". Those marked `attached' are running
and have a controlling terminal. Sessions marked as
`dead' should be thoroughly checked and removed. Ask
your system administrator if you are not sure. Remove
sessions with the -wipe option.
5 -m disables looking in environment variable $STY for
an alternate socket name.
-t name or -k name
sets the title (a.k.a.) for the default shell or
specified program. See also the "shellaka" .screenrc
command.
-wipe
does the same as "screen -ls", but removes destroyed
sessions instead of marking them as `dead'.
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-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" com-
mand.
-O selects a more optimal output mode for your terminal
rather than true vt100 emulation (only affects auto-
margin terminals without `LP'). This can also be set
in your .screenrc by specifying `OP' in a "termcap"
command.
-r [pid.tty.host]
resumes a detached screen session. No other options
(except "-d -r" or "-D -r") may be specified, though
an optional prefix of [pid.]tty.host may be needed to
distinguish between multiple detached screen ses-
sions.
-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 were not specified.
-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.
CUSTOMIZATION
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.
When screen is invoked, it executes initialization com-
mands from the files "/usr/contrib/lib/screenrc" and
".screenrc" in the user's home directory. These are the
"programmer's defaults" that can be overridden in the fol-
lowing ways: For the global screenrc file screen searches
for the environment variable $SYSSCREENRC. The user spe-
cific screenrc file is searchend in $ISCREENRC, then
$SCREENRC, then $HOME/.iscreenrc and finally defaults to
$HOME/.screenrc. The command line option -c takes prece-
dence over the user specific screenrc file. Commands in
these files are used to set options, bind functions to
keys, and to automatically establish one or more extra
windows at the beginning of your screen session. Commands
are listed one per line, with empty lines being ignored.
A command's arguments are separated by tabs or spaces, and
may be surrounded by single or double quotes. A `#' turns
the rest of the line into a comment, except in quotes.
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SCREEN(1) SCREEN(1)
Unintelligible lines are warned about and ignored. Com-
mands may contain references to environment variables. The
syntax is the shell-like "$VAR " or "${VAR}". Note that
this causes incompatibilities with previous screen ver-
sions, as now the '$'-sign has to be protected with '' if
no variable substitution shall be performed.
Customization can also be done 'on-line'. To enter the
command mode type `C-a :'. Setting flags (like scrollback,
login, etc.) on-line may not have the desired effect, as
e.g. the command "C-a : login on" will affect only the
settings for the creation of new windows (just like within
.screenrc). If you intend to change flags of the current
window, then prepend the command with the keyword "set".
E.g. "C-a : set login on" will log this window in.
The following initialization commands are available:
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 (usu-
ally an audible bell). The default message is
'Activity in window %'
Note that monitoring is off for all windows by default,
but can be altered by use of the "monitor" command (C-a
M).
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.
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
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SCREEN(1) SCREEN(1)
'Bell in window %'
An empty message can be supplied to the "bell" command to
suppress output of a message line (bell "").
bind key [function [args]]
Bind a function to a key. By default, each function pro-
vided by screen is bound to one or more keys as indicated
by the above table, e.g. the function to create a new win-
dow is bound to "C-c" and "c". The "bind" command can be
used to redefine the key bindings and to define new bind-
ings. 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 function argument can be one of the follow-
ing keywords:
select0 Switch to window #0
...
select9 Switch to window #9
aka Change the current window's a.k.a.
clear Clear the screen
colon Enter one ".screenrc" command on-the-fly.
copy Select a piece of text.
detach Detach screen
flow Toggle the current window's flow-control setting
hardcopy Make hardcopy of current window
history Use cut&paste to fetch a recently displayed line.
help Display a list of the key bindings in effect
info Display the current window's status information
kill Kill the current window
lastmsg Redisplay the last message line
lock Run a screenlock program.
log Begin/end logging of the current window's output
login Toggle the window's "login" setting (/etc/utmp entry)
monitor Toggle activity monitoring of the current window
next Switch to the next window
other Switch to the window displayed previously
paste Paste in a selected piece of text.
pow_detach Detach screen and logout.
prev Switch to the previous window
quit Kill all windows and terminate
readbuffer Take text from the exchange file.
redisplay Redisplay current window
reset Reset the window to its "power-on" settings
screen Create a new window with the specified command
shell Create a new window with a shell
suspend Suspend screen
termcap Write screen's termcap entry to $HOME/.screencap
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vbell Toggle the window's "vbell" setting.
version Display the version numbers and date last modified
width Toggle the terminal width between 80 and 132 columns
windows Display a list of all windows
wrap Toggle the current window's line-wrap setting
writebuffer Store the selected text in the exchange file.
xoff Send a control-s to the current program
xon Send a control-q to the current program
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 function that displays a
list of windows (so that the function usually invoked by
"C-a C-w" would also be available as "C-a space"), bind
"C-f" to the function "create a window with a TELNET con-
nection to foobar", and bind "escape" to the function 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.
bufferfile exchange-file
Change the filename used for reading and writing with the
copybuffer. The default is "/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 ]
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" com-
mand from within ".screenrc" or by means of "C-a : screen
..." or "C-a c" use this as their default directory.
Without a chdir command, this would be the directory from
which 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.
crlf on|off
This affects the copying of text regions with the `C-a ['
31 January 1992 14
SCREEN(1) SCREEN(1)
command. If it is set to `on', lines will be separated by
the two character sequence `CR' - `LF'. Otherwise only
`LF' is used.
echo [-n] message
The echo command may be used to annoy screen users with a
'message of the day'. Typically installed in a global
/usr/contrib/lib/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 generat-
ing a literal command character to y (just like in the -e
option). Each argument is either a single character, a
two-character sequence of the form "^x" (meaning "C-x"), a
backslash followed by an octal number (specifying the
ASCII code of the character), or a backslash followed by a
second character, such as "\^" or "\\". The default is
"^Aa", but "``" is recommended by one of the authors.
flow on|off|auto [interrupt]
Sets the default flow-control mode for new windows. Spec-
ifying "flow auto interrupt" is the same as the command-
line options -fa and -i. 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.
hardcopyappend 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.
hardstatus on|off
Toggles the use of the terminals 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 should only be used, if the term-
cap/terminfo capabilities "hs", "ts", "fs" and "ds" are
set properly.
login on|off
Sets the login flag which determines if new windows should
have /etc/utmp entries added for them. The login state is
also changeable on-the-fly by using the bindable version
of the "login" command (C-a L) of by means of "C-a : set
login on|off". The default should be "on" for a screen
that runs under suid-root.
31 January 1992 15
SCREEN(1) SCREEN(1)
markkeys string
This is a method of changing the keymap used for
copy/history mode. The string is made up of old-
char=newchar pairs which are separated by `:'. Example:
The string "B=^B:F=^F" will change the keys `C-b' and `C-
f' from their (original emacs-style bindings) to the vi
style binding (scroll up/down full page), which is the
default meaning of `B' and `F'.
mode mode
The mode of each newly allocated pseudo-tty is set to
mode. Mode is an octal number. When no "mode" command is
given, mode 0622 is used.
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 win-
dows.
msgminwait sec
Defines the time screen delays all activity after a mes-
sage was dispayled. 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.
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
$NETHACKOPTIONS.
password [cryptedpw]
Present a crypted password in your ".screenrc" file and
screen will ask for it, whenever a detached session is
tried to be resumed. This is useful, if you have privi-
leged programs running under screen and you want to
31 January 1992 16
SCREEN(1) SCREEN(1)
protect your session from reattach attempts by users that
managed to have your uid. (I.e. any superuser.)
powdetachmsg 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.
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 win-
dow number n is assigned to the newly created window (or,
if this number is already in-use, the next available num-
ber). If a command is specified after "screen", this com-
mand (with the given arguments) is started in the window;
otherwise, a shell is created. Thus, if your ".screenrc"
contains the lines
# example for .screenrc:
screen 1
screen -fn -t foobar 2 telnet foobar
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 win-
dow, 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.
scrollback num
Set the size of the scrollback buffer for new windows to
num lines. The default scrollback is 50 lines. Use "C-a
: set scrollback num" to change the scrollback size of the
current window and use "C-a i" to view the current set-
ting.
redraw on|off
Define whether the display should be refreshed (as done
with "C-a l") after switching to the current window. As
usual when the "set" keyword is given, this command only
affects the current window. But unlike other commands,
"redraw off" (without "set") affects all windows, the win-
dow specific settings come into effect again when "redraw
on" (without "set") is entered.
31 January 1992 17
SCREEN(1) SCREEN(1)
shell command
Set the command to be used to create a new shell. This
overrides the value of the environment variable $SHELL, or
"/bin/sh" if undefined. This is useful if you'd like to
run a tty-enhancer which is expecting to execute the pro-
gram specified in $SHELL.
shellaka a.k.a.
Set the a.k.a. for all shells created during startup or by
the C-A C-c command. For details about what a.k.a.'s are,
see the discussion entitled ALSO KNOWN AS.
sleep num This command will pause the execution of a
.screenrc file for num seconds. It may be used to give
users a chance to read the messages output by "echo".
slowpaste usec
Define the speed text is inserted by the paste ("C-a ]")
command. For each 80 characters (IOSIZE) pasted screen
will make a pause of usec milliseconds to allow the appli-
cation the processing of input. Use that, if you have to
fear that your underlying system chokes on large pastes.
startupmessage on|off
Select whether to display the copyright notice when screen
starts up.
term term
In each window's environment screen opens, it sets the
$TERM variable to "screen" by default, unless no descrip-
tion 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" com-
mand.
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 cus-
tomize the termcap generated for the windows. If your
31 January 1992 18
SCREEN(1) SCREEN(1)
system works with terminfo-database rather than with term-
cap 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 term-
cap 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 TER-
MINAL" 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 Z0=\E[?3h:Z1=\E[?3l
Specifies the firm-margined `LP' capability for all termi-
nals that begin with `vt', and the second line will also
add the escape-sequences to switch into (Z0) and back out
of (Z1) 132-character-per-line mode if this is a vt102 or
vt220. (You must specify Z0 and Z1 in your termcap to use
the width-changing commands.)
termcap vt100 "" l0=PF1:l1=PF2:l2=PF3:l3=PF4
This leaves your vt100 termcap alone and adds the function
key labels to each window's termcap entry.
termcap h19|z19 am@:im=\E@:ei=\EO dc=\E[P
Takes a h19 or z19 termcap and turns off auto-margins
31 January 1992 19
SCREEN(1) SCREEN(1)
(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 the discussion on the "VIR-
TUAL TERMINAL" in this manual, and the termcap(5) man page
for more information on termcap definitions.
vbell on|off
Sets the visual bell setting for new windows. If your ter-
minal does not support a visual bell a message is printed
to the status line. The default message is "Wuff, Wuff!!".
vbellmsg 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".
vbellwait sec
Define a delay in seconds after each display of screen 's
visual bell message. The default is 0 seconds.
wrap on|off
Sets the line-wrap setting for new windows. 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 previ-
ous line. Line-wrap is on by default and can be toggled
with the "wrap" command ("C-a r") or by means of "C-a :
set wrap on|off".
THE MESSAGE LINE
Screen displays informational messages and other diagnos-
tics 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, other-
wise the last line of the screen will be temporarily over-
written 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
31 January 1992 20
SCREEN(1) SCREEN(1)
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<esc>\\'
where '<esc>' is an escape, '^' is a literal up-arrow, and
'\\' turns into a single backslash.
FLOW-CONTROL
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 charac-
ters are used to immediately pause the output of the cur-
rent window. You can still send these characters to the
current program, but you must use the appropriate two-
character screen commands (typically "C-a q" (xon) and "C-
a s" (xoff)). The xon/xoff commands are also useful for
typing C-s and C-q past a terminal that intercepts these
characters.
Each window has an initial flow-control value set with
either the -f option or the "flow" .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 appli-
cation keypad -- when it is enabled, flow-control is
turned off and visa versa. Of course, you can still
manipulate flow-control manually when needed.
If you're running with flow-control enabled and find that
pressing the interrupt key (usually C-c) does not inter-
rupt the display until another 6-8 lines have scrolled by,
try running screen with the "interrupt" option (add the
"interrupt" flag to the "flow" command in your .screenrc,
or use the -i command-line option). This causes the out-
put that screen has accumulated from the interrupted pro-
gram to be flushed. One disadvantage is that the virtual
terminal's memory contains the non-flushed version of the
output, which in rare cases can cause minor inaccuracies
31 January 1992 21
SCREEN(1) SCREEN(1)
in the output. For example, if you switch screens and
return, or update the screen with "C-a l" you would see
the version of the output you would have gotten without
"interrupt" being on. Also, you might need to turn off
flow-control (or use auto-flow mode to turn it off auto-
matically) when running a program that expects you to type
the interrupt character as input, as it is possible to
interrupt the output of the virtual terminal to your phys-
ical terminal when flow-control is enabled. If this hap-
pens, a simple refresh of the screen with "C-a l" will
restore it. Give each mode a try, and use whichever mode
you find more comfortable.
ALSO KNOWN AS (A.K.A.s)
You can customize each window's name in the window display
(viewed with the "windows" command (C-a w)) by setting it
with one of the a.k.a. commands. Normally the name dis-
played is the actual command name of the program created
in the window. However, it is sometimes useful to distin-
guish various programs of the same name or to change the
name on-the-fly to reflect the current state of the win-
dow.
The default name for all shell windows can be set with the
"shellaka" 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 AKA-string escape-sequence (<esc>kname<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 pre-defined names to keys
with the "aka" 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 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 cur-
rent command running in the window to the end of the win-
dow's shell name (e.g. "name:cmd"). Otherwise the current
command name supersedes the shell name while it is run-
ning.
Here's how it works: you must modify your shell prompt to
output a null 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
31 January 1992 22
SCREEN(1) SCREEN(1)
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 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 win-
dow status would show the name "trn" while the command was
running, and revert to "csh" upon completion.
bind R screen -t '% |root:' su
Having this command in your .screenrc would bind the key
sequence "C-a R" to the "su" command and give it an auto-
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 sec-
ond binding would clear an auto-aka's current setting (C-a
E). The third binding would set the current window's
31 January 1992 23
SCREEN(1) SCREEN(1)
a.k.a. to "(unknown)" (C-a u).
One thing to keep in mind when adding a null aka escape-
sequence to your prompt is that some shells (like the csh)
count all the non-control characters as part of the
prompt's length. If these invisible characters aren't a
multiple of 8 then backspacing over a tab will result in
an incorrect display. One way to get around this is to
use a prompt like this:
set prompt='^[[0000m^[k^[\% '
The escape-sequence "<esc>[0000m" not only normalizes the
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 v1.04).
THE VIRTUAL TERMINAL
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 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 substi-
tute.
The idea is that if you have a terminal which doesn't sup-
port an important feature (e.g. delete char or clear to
EOS) you can build a new termcap/terminfo entry for 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.
31 January 1992 24
SCREEN(1) SCREEN(1)
The actual set of capabilities supported by the virtual
terminal depends on the capabilities supported by the
physical terminal. If, for instance, the physical termi-
nal does not support underscore mode, screen does not put
the `us' and `ue' capabilities into the window's $TERMCAP
variable, accordingly. However, a minimum number of capa-
bilities must be supported by a terminal in order to run
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 latter
defined, its value will be copied verbatim into each win-
dow's $TERMCAP variable. This can either be the full ter-
minal 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 term-
cap.
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 charac-
ter sets. This allows an application to make use of, for
instance, the VT100 graphics character set or national
character sets. The following control functions from ISO
2022 are supported: 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 corre-
sponding 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' ter-
minfo 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 termi-
nal. This allows a user to have an application in one
window sending output to a printer connected to the termi-
nal, while all other windows are still active (the printer
port is enabled and disabled again for each chunk of out-
put). As a side-effect, programs running in different
windows can send output to the printer simultaneously.
Data sent to the printer is not displayed in the window.
Some capabilities are only put into the $TERMCAP variable
31 January 1992 25
SCREEN(1) SCREEN(1)
of the virtual terminal if they can be efficiently imple-
mented by the physical terminal. For instance, `dl'
(delete line) is only put into the $TERMCAP variable if
the terminal supports either delete line itself or
scrolling regions. Note that this may provoke confusion,
when the session is reattached on a different terminal, as
the value of $TERMCAP cannot be modified by parent pro-
cesses.
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 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 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)
31 January 1992 26
SCREEN(1) SCREEN(1)
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
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SCREEN(1) SCREEN(1)
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
?3 (V) Change Terminal Width
?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)
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SCREEN(1) SCREEN(1)
ESC [ 4 i (A) Stop relay to printer (ANSI Media Copy)
ENVIRONMENT
COLUMNS
Number of columns on the terminal (overrides term-
cap 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.
FILES
$SYSSCREENRC
/usr/contrib/lib/screenrc screen initialization commands
$ISCREENRC
$SCREENRC
$HOME/.iscreenrc
$HOME/.screenrc Read in after /usr/contrib/lib/screenrc
$ISCREENDIR/S-<login>
$SCREENDIR/S-<login>
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SCREEN(1) SCREEN(1)
/local/screens/S-<login> Socket directories (default)
/usr/tmp/screens/S-<login> Alternate socket directories.
<socket directory>/.termcap Written by the "termcap" output function
/usr/tmp/screens/screen-exchange or
/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.
SEE ALSO
termcap(5), utmp(5), vi(1), captoinfo(1), tic(1)
AUTHORS
Originally created by Oliver Laumann, this latest version
was produced by Wayne Davison, Juergen Weigert and Michael
Schroeder.
CONTRIBUTORS
Allan Ball, Bart Schaefer, Doug Siebert, Howard Chu, Jay
Vassos-Libove, John Kraft, Larry Virden, Marc Boucher,
Nathan Glasser, Patrick Wolfe, Rudolf Koenig. Toerless
Eckert,
VERSION
This is version 3.2. It's 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.
BUGS
`dm' (delete mode), `xn', and `xs' are not handled cor-
rectly (they are ignored).
The GR set of ISO 2022 is not supported.
There is no keyboard input translation to VT100 sequences.
It is not possible to change the environment variable
$TERMCAP when reattaching under a different terminal type.
The support of terminfo based systems is very limited.
Adding extra capabilities to $TERMCAP may not have any
effects.
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".
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SCREEN(1) SCREEN(1)
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.
31 January 1992 31