screen
screen
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 a DEC VT100 terminal and, in addition,
several control functions from the ANSI X3.64 (ISO 6429) and ISO 2022 stan-
dards (e.g. insert/delete line and support for multiple character sets).
There is a scrollback history buffer for each virtual terminal and a copy-
and-paste mechanism that allows moving text regions between windows.
When screen is called, it creates a single window with a shell in it (or
the specified command) and then gets out of your way so that you can use
the program as you normally would. Then, at any time, you can create new
(full-screen) windows with other programs in them (including more shells),
kill existing windows, view a list of windows, turn output logging on and
off, copy-and-paste text between windows, view the scrollback history,
switch between windows in whatever manner you wish, etc. When a program
terminates, screen (per default) kills the window that contained it. If
this window was in the foreground, the display switches to the previous
window; if none are left, screen exits.
Everything you type is sent to the program running in the current window.
The only exception to this is the one keystroke that is used to initiate a
command to the window manager. By default, each command begins with a
control-a (abbreviated C-a from now on), and is followed by one other keys-
troke. The command character and all the key bindings can be fully custom-
ized 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, regard-
less of the state of the process running in the current window. Similarly,
you can create a new window with a custom command in it by first binding
the command to a keystroke (in your .screenrc file or at the "C-a :" com-
mand line) and then using it just like the "C-a c" command. In addition,
new windows can be created by running a command like:
screen emacs prog.c
from a shell prompt within a previously created window. This will not run
another copy of screen, but will instead supply the command name and its
arguments to the window manager (specified in the $STY environment vari-
selected your terminal type, just as you would for any other
termcap/terminfo program. (You can do this by using tset for example.)
If you're impatient and want to get started without doing a lot more read-
ing, you should remember this one command: "C-a ?". Typing these two
characters will display a list of the available screen commands and their
bindings. Each keystroke is discussed in the section "DEFAULT KEY BIND-
INGS". The manual section "CUSTOMIZATION" deals with the contents of your
.screenrc.
If your terminal is a "true" auto-margin terminal (it doesn't allow the
last position on the screen to be updated without scrolling the screen)
consider to use a version of your terminal's termcap that has automatic
margins turned off. This will ensure an accurate and optimal update of the
screen in all circumstances. Most terminals nowadays have "magic" margins
(automatic margins plus usable last column). This is the VT100 style type
and perfectly suited for screen. If all you've got is a "true" auto-margin
terminal screen will be content to use it, but updating a character put
into the last position on the screen may not be possible until the screen
scrolls or the character is moved into a safe position in some other way.
This delay can be shortened by using a terminal with insert-character capa-
bility.
COMMAND-LINE OPTIONS
Screen has the following command-line options:
-a include all capabilities (with some minor exceptions) in each window's
termcap, even if screen must redraw parts of the display in order to
implement a function.
-A Adapt the sizes of all windows to the size of the current terminal.
By default, screen tries to restore its old window sizes when attach-
ing to resizable terminals (those with "WS" in its description, e.g.
suncmd or some xterm).
-c file
override the default configuration file from "$HOME/.screenrc" to
file.
-d|-D [pid.tty.host]
does not start screen, but detaches the elsewhere running screen ses-
sion. It has the same effect as typing "C-a d" from screen's control-
ling terminal. -D is the equivalent to the power detach key. If no
session can be detached, this option is ignored. The combination
"screen -D -r" can be used to `transport' the elsewhere running ses-
sion 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 character generating a
Specifies the history scrollback buffer to be num lines high.
-i will cause the interrupt key (usually C-c) to interrupt the display
immediately when flow-control is on. See the "defflow" .screenrc com-
mand for details. The use of this option is discouraged.
-l and -ln
turns login mode on or off (for /etc/utmp updating). This can also be
defined through the "deflogin" .screenrc command.
-ls and -list
does not start screen, but prints a list of pid.tty.host strings iden-
tifying your screen sessions. Sessions marked `detached' can be
resumed with "screen -r". Those marked `attached' are running and have
a controlling terminal. Sessions marked as `dead' should be thoroughly
checked and removed. Ask your system administrator if you are not
sure. Remove sessions with the -wipe option.
-L tells screen your auto-margin terminal has a writable last-position on
the screen. This can also be set in your .screenrc by specifying `LP'
in a "termcap" command.
-m causes screen to ignore the $STY environment variable. With "screen
-m" creation of a new session is enforced, regardless whether screen
is called from within another screen session or not.
-O selects a more optimal output mode for your terminal rather than true
VT100 emulation (only affects auto-margin terminals without `LP').
This can also be set in your .screenrc by specifying `OP' in a
"termcap" 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 sessions.
-R attempts to resume the first detached screen session it finds. If
successful, all other command-line options are ignored. If no
detached session exists, starts a new session using the specified
options, just as if -R had not been specified. The option is set by
default if screen is run as a login-shell.
-s sets the default shell to the program specified, instead of the value
in the environment variable $SHELL (or "/bin/sh" if not defined).
This can also be defined through the "shell" .screenrc command.
-S sessionname
When creating a new session, this option can be used to specify a
meaningful name for the session. This name identifies the session for
"screen -list" and "screen -r" actions. It substitutes the default
[tty.host] suffix.
DEFAULT KEY BINDINGS
As mentioned, each screen command consists of a "C-a" followed by one other
character. For your convenience, all commands that are bound to lower-case
letters are also bound to their control character counterparts (with the
exception of "C-a a"; see below), thus, "C-a c" as well as "C-a C-c" can be
used to create a window. See section "CUSTOMIZATION" for a description of
the command.
The following table shows the default key bindings:
C-a '
C-a " (select) Prompt for a window name or number to switch to.
C-a 0 (select 0)
... ...
C-a 9 (select 9) Switch to window number 0 - 9.
C-a C-a (other) Toggle to the window displayed previously. Note
that this binding defaults to the command charac-
ter typed twice, unless overridden; for instance,
if you use the option "-e]x", this command
becomes "]]", not "]C-a".
C-a a (meta) Send the command character (C-a) to window. See
escape command.
C-a A (title) Allow the user to enter a name for the current
window.
C-a b
C-a C-b (break) Send a break to window.
C-a B (pow_break) Reopen the terminal line and send a break.
C-a c
C-a C-c (screen) Create a new window with a shell and switch to
that window.
C-a C (clear) Clear the screen.
C-a d
C-a C-d (detach) Detach screen from this terminal.
C-a D D (pow_detach) Detach and logout.
C-a f
C-a C-f (flow) Toggle flow on, off or auto.
C-a C-g (vbell) Toggles screen's visual bell mode.
C-a h (hardcopy) Write a hardcopy of the current window to the
C-a L (login) Toggle this windows login slot. Available only if
screen is configured to update the utmp database.
C-a m
C-a C-m (lastmsg) Repeat the last message displayed in the message
line.
C-a M (monitor) Toggles monitoring of the current window.
C-a space
C-a n
C-a C-n (next) Switch to the next window.
C-a N (number) Show the number (and title) of the current win-
dow.
C-a backspace
C-a h
C-a p
C-a C-p (prev) Switch to the previous window (opposite of C-a
n).
C-a q
C-a C-q (xon) Send a control-q to the current window.
C-a r
C-a C-r (wrap) Toggle the current window's line-wrap setting
(turn the current window's automatic margins on
and off).
C-a s
C-a C-s (xoff) Send a control-s to the current window.
C-a t
C-a C-t (time) Show system information.
C-a v (version) Display the version and compilation date.
C-a C-v (digraph) Enter digraph.
C-a w
C-a C-w (windows) Show a list of window.
C-a W (width) Toggle 80/132 columns.
C-a x
C-a C-x (lockscreen) Lock this terminal.
C-a z
C-a C-z (suspend) Suspend screen. Your system must support BSD-
style job-control.
C-a ] (paste .) Write the contents of the paste buffer to the
stdin queue of the current window.
C-a {
C-a } (history) Copy and paste a previous (command) line.
C-a > (writebuf) Write paste buffer to a file.
C-a < (readbuf) Reads the screen-exchange file into the paste
buffer.
C-a = (removebuf) Removes the file used by C-a < and C-a >.
C-a , (license) Shows where screen comes from, where it went to
and why you can use it.
C-a _ (silence) Start/stop monitoring the current window for
inactivity.
CUSTOMIZATION
The "socket directory" defaults either to $HOME/.screen or simply to
/tmp/screens or preferably to /usr/local/screens chosen at compile-time. If
screen is installed setuid-root, then the administrator should compile
screen with an adequate (not NFS mounted) socket directory. If screen is
not running setuid-root, the user can specify any mode 777 directory in the
environment variable $SCREENDIR.
When screen is invoked, it executes initialization commands from the files
"/usr/local/etc/screenrc" and ".screenrc" in the user's home directory.
These are the "programmer's defaults" that can be overridden in the follow-
ing ways: for the global screenrc file screen searches for the environment
variable $SYSSCREENRC (this override feature may be disabled at compile-
time). The user specific screenrc file is searched in $ISCREENRC, then
$SCREENRC, then $HOME/.iscreenrc and finally defaults to $HOME/.screenrc.
The command line option -c takes precedence over the above user screenrc
files.
Commands in these files are used to set options, bind functions to keys,
and to automatically establish one or more windows at the beginning of your
screen session. Commands are listed one per line, with empty lines being
ignored. A command's arguments are separated by tabs or spaces, and may be
surrounded by single or double quotes. A `#' turns the rest of the line
into a comment, except in quotes. Unintelligible lines are warned about
and ignored. Commands may contain references to environment variables. The
syntax is the shell-like "$VAR " or "${VAR}". Note that this causes incom-
patibility with previous screen versions, as now the '$'-character has to
be protected with '\' if no variable substitution shall be performed. A
string in single-quotes is also protected from variable substitution.
aclchg usernames permbits list
Change permissions for a comma seperated list of users. Permission bits are
represented as `r', `w' and `x'. Prefixing `+' grants the permission, `-'
removes it. The third parameter is a comma seperated list of commands
and/or windows (specified either by number or title). The special list `#'
refers to all windows, `?' to all commands. if usernames consists of a sin-
gle `*', all known users are affected. A command can be executed when the
user has the `x' bit for it. The user can type input to a window when he
has its `w' bit set and no other user obtains a writelock for this window.
Other bits are currently ignored. To withdraw the writelock from another
user in window 2: `aclchg username -w+w 2'. To allow readonly access to
the session: `aclchg username -w "#"'. As soon as a user's name is known to
screen he can attach to the session and (per default) has full permissions
for all command and windows. Execution permission for the acl commands,
`at' and others should also be removed or the user may be able to regain
write permission. Multi user mode only.
acldel username
Remove a user from screen's access control list. If currently attached, all
the user's displays are detached from the session. He cannot attach again.
Multi user mode only.
activity message
When any activity occurs in a background window that is being monitored,
screen displays a notification in the message line. The notification mes-
sage can be re-defined by means of the "activity" command. Each occurrence
of `%' in message is replaced by the number of the window in which activity
has occurred, and each occurrence of `~' is replaced by the definition for
bell in your termcap (usually an audible bell). The default message is
'Activity in window %'
Note that monitoring is off for all windows by default, but can be altered
by use of the "monitor" command (C-a M).
allpartial on|off
If set to on, only the current cursor line is refreshed on window change.
This affects all windows and is useful for slow terminal lines. The previ-
ous setting of full/partial refresh for each window is restored with
"allpartial off". This is a global flag that immediately takes effect on
all windows overriding the "partial" settings. It does not change the
default redraw behaviour of newly created windows.
at [identifier][#|*|%] command [args ... ]
Execute a command at other displays or windows as if it had been entered
there. "At" changes the context (the `current window' or `current display'
autodetach on|off
Sets whether screen will automatically detach upon hangup, which saves all
your running programs until they are resumed with a screen -r command.
When turned off, a hangup signal will terminate screen and all the
processes it contains. Autodetach is on by default.
autonuke on|off
Sets whether a clear screen sequence should nuke all the output that has
not been written to the terminal. See also "obuflimit".
bell message
When a bell character is sent to a background window, screen displays a
notification in the message line. The notification message can be re-
defined by means of the "bell" command. Each occurrence of `%' in message
is replaced by the number of the window to which a bell has been sent, and
each occurrence of `~' is replaced by the definition for bell in your
termcap (usually an audible bell). The default message is
'Bell in window %'
An empty message can be supplied to the "bell" command to suppress output
of a message line (bell "").
bind key [command [args]]
Bind a command to a key. By default, most of the commands provided by
screen are bound to one or more keys as indicated in the "DEFAULT KEY BIND-
INGS" section, e.g. the command to create a new window is bound to "C-c"
and "c". The "bind" command can be used to redefine the key bindings and
to define new bindings. The key argument is either a single character, a
two-character sequence of the form "^x" (meaning "C-x"), a backslash fol-
lowed by an octal number (specifying the ASCII code of the character), or a
backslash followed by a second character, such as "\^" or "\\". The argu-
ment can also be quoted, if you like. If no further argument is given, any
previously established binding for this key is removed. The command argu-
ment can be any command listed in this section.
Some examples:
bind ' ' windows
bind ^f screen telnet foobar
bind \033 screen -ln -t root -h 1000 9 su
would bind the space key to the command that displays a list of windows (so
that the command usually invoked by "C-a C-w" would also be available as
"C-a space"), bind "C-f" to the command "create a window with a TELNET con-
nection to foobar", and bind "escape" to the command that creates an non-
login window with a.k.a. "root" in slot #9, with a super-user shell and a
scrollback buffer of 1000 lines.
Some keys on a VT100 terminal can send a different string if application
mode is turned on (e.g the cursor keys). Such keys have two entries in the
translation table. You can select the application mode entry by specifying
the -a option.
The -t option tells screen not to do intercharacter timing. One cannot turn
off the timing if a termcap capabilty is used.
Cmd can be any of screen's commands with an arbitrary number of args. If
cmd is omitted the keybinding is removed from the table.
Here are some examples of keyboard bindings:
bindkey -d
Show all of the default key bindings. The application mode entries are
marked with [A].
bindkey -k k1 select 1
Make the "F1" key switch to window one.
bindkey -t foo stuff barfoo
Make "foo" an abrevation of the word "barfoo". Timeout is disabled so that
users can type slowly.
bindkey "\024" mapdefault
This keybinding makes "^T" an escape character for keybindings. If you did
the above "stuff barfoo" binding, you can enter the word "foo" by typing
"^Tfoo". If you want to insert a "^T" you have to press the key twice (i.e.
escape the escape binding).
bindkey -k F1 command
Make the F11 (not F1!) key an alternative screen escape (besides ^A).
break [duration]
Send a break signal for duration*0.25 seconds to this window. Most useful
if a character device is attached to the window rather than a shell pro-
cess.
bufferfile [exchange-file]
Change the filename used for reading and writing with the paste buffer. If
the optional argument to the "bufferfile" command is omitted, the default
setting ("/tmp/screen-exchange") is reactivated. The following example
will paste the system's password file into the screen window (using the
paste buffer, where a copy remains):
C-a : bufferfile /etc/passwd
C-a < C-a ]
C-a : bufferfile
c1 [on|off]
Change c1 code processing. "C1 on" tells screen to treat the input charac-
ters between 128 and 159 as control functions. Such an 8-bit code is nor-
characters internally by appending '.' chars). New windows have "BBBB02" as
default charset, unless a "kanji" command is active.
The current setting can be viewed with the "info" command.
chdir [directory]
Change the current directory of screen to the specified directory or, if
called without an argument, to your home directory (the value of the
environment variable $HOME). All windows that are created by means of the
"screen" command from within ".screenrc" or by means of "C-a : screen ..."
or "C-a c" use this as their default directory. Without a chdir command,
this would be the directory from which screen was invoked. Hardcopy and
log files are always written to the window's default directory, not the
current directory of the process running in the window. You can use this
command multiple times in your .screenrc to start various windows in dif-
ferent default directories, but the last chdir value will affect all the
windows you create interactively.
clear
Clears the current window and saves its image to the scrollback buffer.
colon
Allows you to enter ".screenrc" command lines. Useful for on-the-fly modif-
ication of key bindings, specific window creation and changing settings.
Note that the "set" keyword no longer exists! Usually commands affect the
current window rather than default settings for future windows. Change
defaults with commands starting with 'def...'.
If you consider this as the `Ex command mode' of screen, you may regard
"C-a esc" (copy mode) as its `Vi command mode'.
command
This command has the same effect as typing the screen escape character
(^A). It is probably only useful for key bindings. See also "bindkey".
console [on|off]
Grabs or ungrabs the machines console output to a window.
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
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 respectively.
Y and y used to mark one whole line or to mark from start of line.
W marks exactly one word.
Repeat count:
Any of these commands can be prefixed with a repeat count number by
pressing digits
0..9 which is taken as a repeat count.
Example: "C-a C-[ H 10 j 5 Y" will copy lines 11 to 15 into the paste
buffer.
Searching:
/ Vi-like search forward.
? Vi-like search backward.
C-a s Emacs style incremental search forward.
C-r Emacs style reverse i-search.
Specials:
There are however some keys that act differently than in vi. Vi does
not allow one to yank rectangular blocks of text, but screen does.
Press
c or C to set the left or right margin respectively. If no repeat count
is given, both default to the current cursor position.
Example: Try this on a rather full text screen: "C-a [ M 20 l SPACE c
10 l 5 j C SPACE".
This moves one to the middle line of the screen, moves in 20 columns
left, marks the beginning of the paste buffer, sets the left column,
moves 5 columns down, sets the right column, and then marks the end of
the paste buffer. Now try:
"C-a [ M 20 l SPACE 10 l 5 j SPACE"
and notice the difference in the amount of text copied.
J joins lines. It toggles between 3 modes: lines separated by a newline
character (012), lines glued seamless, lines separated by a single whi-
tespace. Note that you can prepend the newline character with a car-
riage return character, by issuing a "crlf on".
v is for all the vi users with ":set numbers" - it toggles the left mar-
gin between column 9 and 1. Press
a before the final space key to toggle in append mode. Thus the contents
of the paste buffer will not be overwritten, but is appended to.
A toggles in append mode and sets a (second) mark.
> sets the (second) mark and writes the contents of the paste buffer to
the screen-exchange file (/tmp/screen-exchange per default) once copy-
mode is finished.
This example demonstrates how to dump the whole scrollback buffer to
that file: "C-A [ g SPACE G $ >".
C-g gives information about the current line and column.
x exchanges the first mark and the current cursor position. You can use
this to adjust an already placed mark.
Turns runtime debugging on or off. If screen has been compiled with option
-DDEBUG debugging available and is turned on per default. Note that this
command only affects debugging output from the main "SCREEN" process.
defc1 on|off
Same as the c1 command except that the default setting for new windows is
changed. Initial setting is `on'.
defautonuke on|off
Same as the autonuke command except that the default setting for new
displays is changed. Initial setting is `off'. Note that you can use the
special `AN' terminal capability if you want to have a dependency on the
terminal type.
defcharset [set]
Like the charset command except that the default setting for new windows is
changed. Shows current default if called without argument.
defescape xy
Set the default command characters. This is equivalent to the "escape"
except that it is useful multiuser sessions only. In a multiuser session
"escape" changes the command character of the calling user, where "defes-
cape" changes the default command characters for users that will be added
later.
defflow on|off|auto [interrupt]
Same as the flow command except that the default setting for new windows is
changed. Initial setting is `auto'. Specifying "defflow auto interrupt" is
the same as the command-line options -fa and -i.
defgr on|off
Same as the gr command except that the default setting for new windows is
changed. Initial setting is `off'.
defhstatus [status]
The hardstatus line that all new windows will get is set to status. This
command is useful to make the hardstatus of every window display the window
number or title or the like. Status may contain the same directives as in
the window messages, but the directive escape character is '^E' (octal 005)
instead of '%'. This was done to make a misinterpretion of program gen-
erated hardstatus lines impossible. If the parameter status is omitted,
the current default string is displayed. Per default the hardstatus line
of new windows is empty.
The mode of each newly allocated pseudo-tty is set to mode. Mode is an
octal number. When no "defmode" command is given, mode 0622 is used.
defmonitor on|off
Same as the monitor command except that the default setting for new windows
is changed. Initial setting is `off'.
defobuflimit limit
Same as the obuflimit command except that the default setting for new
displays is changed. Initial setting is 256 bytes. Note that you can use
the special 'OL' terminal capability if you want to have a dependency on
the terminal type.
defscrollback num
Same as the scrollback command except that the default setting for new win-
dows is changed. Initial setting is 100.
defwrap on|off
Same as the wrap command except that the default setting for new windows is
changed. Initially line-wrap is on and can be toggled with the "wrap" com-
mand ("C-a r") or by means of "C-a : wrap on|off".
defwritelock on|off|auto
Same as the writelock command except that the default setting for new win-
dows is changed. Initially writelocks will operate in automatic mode.
defzombie [keys]
Synonym to the zombie command. Both currently change the default. See
there.
detach
Detach the screen session (disconnect it from the terminal and put it into
the background). This returns you to the shell where you invoked screen.
A detached screen can be resumed by invoking screen with the -r option.
(See also section "COMMAND-LINE OPTIONS".)
digraph [preset]
This command prompts the user for a digraph sequence. The next two charac-
ters typed are looked up in a builtin table and the resulting character is
inserted in the input stream. For example, if the user enters 'a"', an a-
umlaut will be inserted. If the first character entered is a 0 (zero),
screen will treat the following charcters (up to three) as an octal number
instead. The optional argument preset is treated as user input, thus one
can create an "umlaut" key. For example the command "bindkey ^K digraph
The echo command may be used to annoy screen users with a 'message of the
day'. Typically installed in a global /local/etc/screenrc. See also
"sleep". Echo is also useful for online checking of environment variables.
escape xy
Set the command character to x and the character generating a literal com-
mand character to y (just like in the -e option). Each argument is either
a single character, a two-character sequence of the form "^x" (meaning
"C-x"), a backslash followed by an octal number (specifying the ASCII code
of the character), or a backslash followed by a second character, such as
"\^" or "\\". The default is "^Aa".
exec [[fdpat] newcommand [args ...]]
Run a subprocess (newcommand) in the current window. The flow of data
between newcommand's stdin/stdout/stderr, the process already running
(shell) and screen itself (window) is controlled by the filedescriptor pat-
tern 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 (:) com-
bines both. User input will go to newcommand unless newcommand requests
the old process' output (fdpats first character is `!' or `:') or a pipe
(|) is added to the end of fdpat.
Invoking `exec' without arguments shows name and arguments of the currently
running subprocess in this window.
When a subprocess is running the `kill' command will affect it instead of
the windows process.
Refer to the postscript file `fdpat.ips' for a confusing illustration of
all 21 possible combinations. Each drawing shows the digits 2,1,0
representing the three file descriptors of newcommand. The box marked `W'
is usual pty that has the application-process on its slave side. The box
marked `P' is the secondary pty that now has screen at its master side.
Abbreviations:
Whitespace between the word `exec' and fdpat and the command can be omit-
ted. Trailing dots and a fdpat consisting only of dots can be omitted. A
simple `|' is synonymous for the pattern `!..|'; the word exec can be omit-
ted here and can always be replaced by `!'.
Examples:
exec ... /bin/sh
exec /bin/sh
!/bin/sh
Creates another shell in the same window, while the original shell is still
running. Output of both shells is displayed and user input is sent to the
new /bin/sh.
exec !.. stty 19200
!:sed -n s/.*Error.*/\007/p
Sends window output to both, the user and the sed command. The sed inserts
an additional bell character (oct. 007) to the window output seen by
screen. This will cause "Bell in window x" messages, whenever the string
"Error" appears in the window.
flow [on|off|auto]
Sets the flow-control mode for this window. Without parameters it cycles
the current window's flow-control setting from "automatic" to "on" to
"off". See the discussion on "FLOW-CONTROL" later on in this document for
full details and note, that this is subject to change in future releases.
Default is set by `defflow'.
gr [on|off]
Turn GR charset switching on/off. Whenever screens sees an input char with
an 8th bit set, it will use the charset stored in the GR slot and print the
character with the 8th bit stripped. The default (see also "defgr") is not
to process GR switching because otherwise the ISO88591 charset would not
work.
hardcopy
Writes out the currently displayed image to a file hardcopy.n in the
window's default directory, where n is the number of the current window.
This either appends or overwrites the file if it exists. See below.
hardcopy_append on|off
If set to "on", screen will append to the "hardcopy.n" files created by the
command "C-a h", otherwise these files are overwritten each time. Default
is `off'.
hardcopydir directory
Defines a directory where hardcopy files will be placed. If unset, hard-
copys are dumped in screen's current working directory.
hardstatus [on|off]
Toggles the use of the terminal's hardware status line. If "on", screen
will use this facility to display one line messages. Otherwise these mes-
sages are overlayed in reverse video mode at the display line. Note that
the hardstatus feature can only be used if the termcap/terminfo capabili-
ties "hs", "ts", "fs" and "ds" are set properly. Default is `on' whenever
the "hs" capability is present.
height [lines]
history
Usually users work with a shell that allows easy access to previous com-
mands. For example csh has the command "!!" to repeat the last command
executed. Screen allows you to have a primitive way of re-calling "the
command that started ...": You just type the first letter of that command,
then hit `C-a {' and screen tries to find a previous line that matches with
the `prompt character' to the left of the cursor. This line is pasted into
this window's input queue. Thus you have a crude command history (made up
by the visible window and its scrollback buffer).
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 termi-
nal character sets that are currently designated as G0 through G3. For
system information use the "time" command.
ins_reg [key]
No longer exists, use "paste" instead.
kanji jis|euc|sjis [jis|euc|sjis]
Tell screen how to process kanji input/output. The first argument sets the
kanji type of the current window. Each window can emulate a different type.
The optional second parameter tells screen how to write the kanji codes to
the connected terminal. The preferred method of setting the display type is
to use the "KJ" termcap entry. See also "defkanji", which changes the
default setting of a new window.
kill
Kill current window.
If there is an `exec' command running then it is killed. Otherwise the pro-
cess (shell) running in the window receives a HANGUP condition, the window
structure is removed and screen switches to the previously displayed win-
dow. When the last window is destroyed, screen exits. Note: Emacs users
should keep this command in mind, when killing a line. It is recommended
not to use "C-a" as the screen escape key or to rebind kill to "C-a K".
lastmsg
Redisplay the last contents of the message/status line. Useful if you're
typing when a message appears, because the message goes away when you
press a key (unless your terminal has a hardware status line). Refer to
the commands "msgwait" and "msgminwait" for fine tuning.
$LOCKPRG (which must be set in the shell from which screen is started) and
is executed with the user's uid and gid.
log [on|off]
Start/stop writing output of the current window to a file "screenlog.n" in
the window's default directory, where n is the number of the current win-
dow. This filename can be changed with the `logfile' command. If no parame-
ter is given, the state of logging is toggled. The session log is appended
to the previous contents of the file if it already exists. The current con-
tents and the contents of the scrollback history are not included in the
session log. Default is `off'.
logfile filename
Defines the name the logfiles will get. The default is "screenlog.%n".
login [on|off]
Adds or removes the entry in the utmp database file for the current window.
This controls if the window is `logged in'. When no parameter is given,
the login state of the window is toggled. Additionally to that toggle, it
is convenient having a `log in' and a `log out' key. E.g. `bind I login on'
and `bind O login off' will map these keys to be C-a I and C-a O. The
default setting (in config.h.in) should be "on" for a screen that runs
under suid-root. Use the "deflogin" command to change the default login
state for new windows. Both commands are only present when screen has been
compiled with utmp support.
mapdefault
Tell screen that the next input character should only be looked up in the
default bindkey table. See also "bindkey".
mapnotnext
Like mapdefault, but don't even look in the default bindkey table.
maptimeout [timo]
Set the intercharacter timer for input sequence detection to a timeout of
timo ms. The default timeout is 300ms. Maptimeout with no arguments shows
the current setting. See also "bindkey".
markkeys string
This is a method of changing the keymap used for copy/history mode. The
string is made up of oldchar=newchar pairs which are separated by `:'.
Example: The string "B=^B:F=^F" will change the keys `C-b' and `C-f' to the
vi style binding (scroll up/down fill page). This happens to be the
default binding for `B' and `F'. The command "markkeys h=^B:l=^F:$=^E"
would set the mode for an emacs-style binding.
msgminwait sec
Defines the time screen delays a new message when one message is currently
displayed. The default is 1 second.
msgwait sec
Defines the time a message is displayed if screen is not disturbed by other
activity. The default is 5 seconds.
multiuser on|off
Switch between singleuser and multiuser mode. Standard screen operation is
singleuser. In multiuser mode the commands `acladd', `aclchg' and `acldel'
can be used to enable (and disable) other users accessing this screen.
nethack on|off
Changes the kind of error messages used by screen. When you are familiar
with the game "nethack", you may enjoy the nethack-style messages which
will often blur the facts a little, but are much funnier to read. Anyway,
standard messages often tend to be unclear as well.
This option is only available if screen was compiled with the NETHACK flag
defined. The default setting is then determined by the presence of the
environment variable $NETHACKOPTIONS.
next
Switch to the next window. This command can be used repeatedly to cycle
through the list of windows.
number [n]
Change the current windows number. If the given number n is already used by
another window, both windows exchange their numbers. If no argument is
specified, the current window number (and title) is shown.
obuflimit [limit]
If the output buffer contains more bytes than the specified limit, no more
data will be read from the windows. The default value is 256. If you have a
fast display (like xterm), you can set it to some higher value. If no argu-
ment is specified, the current setting is displayed.
other
Switch to the window displayed previously.
partial on|off
Defines whether the display should be refreshed (as with redisplay) after
twice for typing a password and places its encryption in the paste buffer.
Default is `none', this disables password checking.
paste [registers[dest_reg]]
Write the (concatenated) contents of the specified registers to the stdin
queue of the current window. The register '.' is treated as the paste
buffer. If no parameter is given the user is prompted for a single register
to paste. The paste buffer can be filled with the copy, history and read-
buf commands. Other registers can be filled with the register, readreg and
paste commands. If paste is called with a second argument, the contents of
the specified registers is pasted into the named destination register
rather than the window. If '.' is used as the second argument, the displays
paste buffer is the destination. Note, that "paste" uses a wide variety of
resources: Whenever a second argument is specified no current window is
needed. When the source specification only contains registers (not the
paste buffer) then there need not be a current display (terminal attached),
as the registers are a global resource. The paste buffer exists once for
every user.
pastefont [on|off]
Tell screen to include font information in the paste buffer. The default is
not to do so. This command is especially usefull for multi character fonts
like kanji.
pow_break
Reopen the window's terminal line and send a break condition. See `break'.
pow_detach
Power detach. Mainly the same as detach, but also sends a HANGUP signal to
the parent process of screen. CAUTION: This will result in a logout, when
screen was started from your login shell.
pow_detach_msg message
The message specified here is output whenever a `Power detach' was per-
formed. It may be used as a replacement for a logout message or to reset
baud rate, etc.
prev
Switch to the window with the next lower number. This command can be used
repeatedly to cycle through the list of windows.
printcmd [cmd]
If cmd is not an empty string, screen will not use the terminal capabili-
ties "po/pf" if it detects an ansi print sequence ESC [ 5 i, but pipe the
output into cmd. This should normally be a command like "lpr" or "'cat >
quit
Kill all windows and terminate screen. Note that on VT100-style terminals
the keys C-4 and C-\ are identical. This makes the default bindings
dangerous: Be careful not to type C-a C-4 when selecting window no. 4. Use
the empty bind command (as in "bind '^\'") to remove a key binding.
readbuf
Reads the contents of the current screen-exchange file into the paste
buffer. See also "bufferfile" command.
readreg [register [filename]]
Does one of two things, dependent on number of arguments: with zero or one
arguments it it duplicates the paste buffer contents into the register
specified or entered at the prompt. With two arguments it reads the con-
tents of the named file into the register, just as readbuf reads the
screen-exchange file into the paste buffer. The following example will
paste the system's password file into the screen window (using register p,
where a copy remains):
C-a : readreg p /etc/passwd
C-a : paste p
redisplay
Redisplay the current window. Needed to get a full redisplay when in par-
tial redraw mode.
register key string
Save the specified string to the register key. See also the "paste" com-
mand.
removebuf
Unlinks the screen-exchange file used by the commands "writebuf" and "read-
buf".
reset
Reset the virtual terminal to its "power-on" values. Useful when strange
settings (like scroll regions or graphics character set) are left over from
an application.
screen [-opts] [n] [cmd [args]]
Establish a new window. The flow-control options (-f, -fn and -fa), title
(a.k.a.) option (-t), login options (-l and -ln) , terminal type option (-T
<term>) and scrollback option (-h <num>) may be specified for each command.
If an optional number n in the range 0..9 is given, the window number n is
switches to the last window specified in your .screenrc file or, if none,
opens a default window #0.
scrollback num
Set the size of the scrollback buffer for the current windows to num lines.
The default scrollback is 100 lines. See also the "defscrollback" command
and use "C-a i" to view the current setting.
select [n]
Switch to the window with the number n. If no window number is specified,
you get prompted for an identifier. This can be title (alphanumeric window
name) or a number. When a new window is established, the first available
number is assigned to this window. Thus, the first window can be activated
by "select 0" (there can be no more than 10 windows present simultaneously
unless screen was compiled with a higher MAXWIN setting).
sessionname [name]
Rename the current session. Note, that for "screen -list" the name shows up
with the process-id prepended. If the argument "name" is omitted, the name
of this session is displayed. Caution: The $STY environment variables still
reflects the old name. This may result in confusion. The default is con-
structed from the tty and host names.
setenv [var [string]]
Set the environment variable var to value string. If only var is speci-
fied, the user will be prompted to enter a value. If no parameters are
specified, the user will be prompted for both variable and value. The
environment is inherited by all subsequently forked shells.
shell command
Set the command to be used to create a new shell. This overrides the value
of the environment variable $SHELL. This is useful if you'd like to run a
tty-enhancer which is expecting to execute the program specified in $SHELL.
If the command begins with a '-' character, the shell will be started as a
login-shell.
shelltitle title
Set the title for all shells created during startup or by the C-A C-c com-
mand. For details about what a title is, see the discussion entitled
"TITLES (naming windows)".
silence [on|off|sec]
Toggles silence monitoring of windows. When silence is turned on and an
affected window is switched into the background, you will receive the
silence notification message in the status line after a specified period of
chance to read the messages output by "echo".
slowpaste usec
Define the speed at which text is inserted by the paste ("C-a ]") command.
If the slowpaste value is nonzero text is written character by character.
screen will make a pause of usec milliseconds after each single character
write to allow the application to process its input. Only use slowpaste if
your underlying system exposes flow control problems while pasting large
amounts of text.
sorendition [attr [color]]
Change the way screen does highlighting for text marking and printing mes-
sages. Attr is a hexadecimal number and describes the attributes (inverse,
underline, ...) the text will get. Color is a 2 digit number and changes
the forground/background of the highlighted text. Some knowledge of
screen's internal character representation is needed to make the characters
appear in the desired way. The default is currently 10 99 (standout,
default colors).
startup_message on|off
Select whether you want to see the copyright notice during startup.
Default is `on', as you probably noticed.
stuff string
Stuff the string string in the input buffer of the current window. This is
like the "paste" command but with much less overhead. You cannot paste
large buffers with the tuff" command. It is most useful for key bindings.
See also "bindkey".
suspend
Suspend screen. The windows are in the `detached' state, while screen is
suspended. This feature relies on the shell being able to do job control.
term term
In each window's environment screen opens, the $TERM variable is set to
"screen" by default. But when no description for "screen" is installed in
the local termcap or terminfo data base, you set $TERM to - say - "vt100".
This won't do much harm, as screen is VT100/ANSI compatible. The use of
the "term" command is discouraged for non-default purpose. That is, one
may want to specify special $TERM settings (e.g. vt100) for the next
"screen rlogin othermachine" command. Use the command "screen -T vt100 rlo-
gin othermachine" rather than setting and resetting the default.
termcap term terminal-tweaks [window-tweaks]
terminfo term terminal-tweaks [window-tweaks]
termcapinfo term terminal-tweaks [window-tweaks]
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, enhanc-
ing it or overriding existing values. The first tweak modifies your
terminal's termcap, and contains definitions that your terminal uses to
perform certain functions. Specify a null string to leave this unchanged
(e.g. ''). The second (optional) tweak modifies all the window termcaps,
and should contain definitions that screen understands (see the "VIRTUAL
TERMINAL" section).
Some examples:
termcap xterm* LP:hs@
Informs screen that all terminals that begin with `xterm' have firm auto-
margins that allow the last position on the screen to be updated (LP), but
they don't really have a status line (no 'hs' - append `@' to turn entries
off). Note that we assume `LP' for all terminal names that start with
"vt", but only if you don't specify a termcap command for that terminal.
termcap vt* LP termcap vt102|vt220 Z0=\E[?3h:Z1=\E[?3l
Specifies the firm-margined `LP' capability for all terminals that begin
with `vt', and the second line will also add the escape-sequences to switch
into (Z0) and back out of (Z1) 132-character-per-line mode if this is a
VT102 or VT220. (You must specify Z0 and Z1 in your termcap to use the
width-changing commands.)
termcap vt100 "" l0=PF1:l1=PF2:l2=PF3:l3=PF4
This leaves your vt100 termcap alone and adds the function key labels to
each window's termcap entry.
termcap h19|z19 am@:im=\E@:ei=\EO dc=\E[P
Takes a h19 or z19 termcap and turns off auto-margins (am@) and enables the
insert mode (im) and end-insert (ei) capabilities (the `@' in the `im'
string is after the `=', so it is part of the string). Having the `im' and
`ei' definitions put into your terminal's termcap will cause screen to
automatically advertise the character-insert capability in each window's
termcap. Each window will also get the delete-character capability (dc)
added to its termcap, which screen will translate into a line-update for
the terminal (we're pretending it doesn't support character deletion).
If you would like to fully specify each window's termcap entry, you should
instead set the $SCREENCAP variable prior to running screen. See the dis-
cussion on the "VIRTUAL TERMINAL" in this manual, and the termcap(5) man
page for more information on termcap definitions.
Unset an environment variable.
vbell on|off
If your terminal does not support a visual bell, a `vbell-message' is
displayed in the status line. Sets the visual bell setting for this win-
dow. If your terminal does not support a visual bell, a `vbell-message' is
displayed in the status line. Refer to the termcap variable `vb' (ter-
minfo: 'flash').
vbell_msg message
Sets the visual bell message. message is printed to the status line if the
window receives a bell character (^G) and vbell is set to "on". The
default message is "Wuff, Wuff!!".
vbellwait sec
Define a delay in seconds after each display of screen's visual bell mes-
sage. The default is 1 second.
version
Print the current version and the compile date in the status line.
wall message
Write a message to all displays. The message will appear in the terminal's
status line.
width [num]
Toggle the window width between 80 and 132 columns or set it to num columns
if an argument is specified. This requires a capable terminal and the
termcap entries "Z0" and "Z1". See the "termcap" command for more informa-
tion.
windows
Uses the message line to display a list of all the windows. Each window is
listed by number with the name of process that has been started in the win-
dow (or its title); the current window is marked with a `*'; the previous
window is marked with a `-'; all the windows that are "logged in" are
marked with a `$'; a background window that has received a bell is marked
with a `!'; a background window that is being monitored and has had
activity occur is marked with an `@'; a window which has output logging
turned on is marked with `(L)'; windows occupied by other users are marked
with `&'; windows in the zombie state are marked with `Z'. If this list is
too long to fit on the terminal's status line only the portion around the
current window is displayed.
bufferfile command and defaults to "/tmp/screen-exchange".
writelock [on|off|auto]
In addition to access control lists, not all users may be able to write to
the same window at once. Per default, writelock is in `auto' mode and
grants exclusive input permission to the user who is the first to switch to
the particular window. When he leaves the window, other users may obtain
the writelock (automatically). The writelock of the current window is dis-
abled by the command "writelock off". If the user issues the command "wri-
telock on" he keeps the exclusive write permission while switching to other
windows.
xoff
xon
Insert a CTRL-s / CTRL-q character to the stdin queue of the current win-
dow.
zombie [keys]
defzombie [keys]
Per default screen windows are removed from the window list as soon as the
windows process (e.g. shell) exits. When a string of two keys is specified
to the zombie command, `dead' windows will remain in the list. The kill
kommand may be used to remove such a window. Pressing the first key in the
dead window has the same effect. When pressing the second key, screen will
attempt to resurrect the window. The process that was initially running in
the window will be launched again. Calling zombie without parameters will
clear the zombie setting, thus making windows disappear when their process
exits.
As the zombie-setting is manipulated globally for all windows, this command
should only be called defzombie. Until we need this as a per window set-
ting, the commands zombie and defzombie are synonymous.
THE MESSAGE LINE
Screen displays informational messages and other diagnostics in a message
line. While this line is distributed to appear at the bottom of the
screen, it can be defined to appear at the top of the screen during compi-
lation. If your terminal has a status line defined in its termcap, screen
will use this for displaying its messages, otherwise a line of the current
screen will be temporarily overwritten and output will be momentarily
interrupted. The message line is automatically removed after a few seconds
delay, but it can also be removed early (on terminals without a status
line) by beginning to type.
The message line facility can be used by an application running in the
current window by means of the ANSI Privacy message control sequence. For
instance, from within the shell, try something like:
response to an XOFF. With flow-control turned on, XON and XOFF characters
are used to immediately pause the output of the current window. You can
still send these characters to the current program, but you must use the
appropriate two-character screen commands (typically "C-a q" (xon) and "C-a
s" (xoff)). The xon/xoff commands are also useful for typing C-s and C-q
past a terminal that intercepts these characters.
Each window has an initial flow-control value set with either the -f option
or the "defflow" .screenrc command. Per default the windows are set to
automatic flow-switching. It can then be toggled between the three states
'fixed on', 'fixed off' and
The automatic flow-switching mode deals with flow control using the TIOCPKT
mode (like "rlogin" does). If the tty driver does not support TIOCPKT,
screen tries to find out the right mode based on the current setting of the
application keypad - when it is enabled, flow-control is turned off and
visa versa. Of course, you can still manipulate flow-control manually when
needed.
If you're running with flow-control enabled and find that pressing the
interrupt key (usually C-c) does not interrupt the display until another
6-8 lines have scrolled by, try running screen with the "interrupt" option
(add the "interrupt" flag to the "flow" command in your .screenrc, or use
the -i command-line option). This causes the output that screen has accu-
mulated from the interrupted program to be flushed. One disadvantage is
that the virtual terminal's memory contains the non-flushed version of the
output, which in rare cases can cause minor inaccuracies in the output.
For example, if you switch screens and return, or update the screen with
"C-a l" you would see the version of the output you would have gotten
without "interrupt" being on. Also, you might need to turn off flow-
control (or use auto-flow mode to turn it off automatically) when running a
program that expects you to type the interrupt character as input, as it is
possible to interrupt the output of the virtual terminal to your physical
terminal when flow-control is enabled. If this happens, a simple refresh
of the screen with "C-a l" will restore it. Give each mode a try, and use
whichever mode you find more comfortable.
TITLES (naming windows)
You can customize each window's name in the window display (viewed with the
"windows" command (C-a w)) by setting it with one of the title commands.
Normally the name displayed is the actual command name of the program
created in the window. However, it is sometimes useful to distinguish
various programs of the same name or to change the name on-the-fly to
reflect the current state of the window.
The default name for all shell windows can be set with the "shelltitle"
command in the .screenrc file, while all other windows are created with a
"screen" command and thus can have their name set with the -t option.
Interactively, there is the title-string escape-sequence (<esc>kname<esc>\)
and the "title" command (C-a A). The former can be output from an applica-
title-escape-sequence (<esc>k<esc>\) as a part of your prompt. The last
part of your prompt must be the same as the string you specified for the
search portion of the title. Once this is set up, screen will use the
title-escape-sequence to clear the previous command name and get ready for
the next command. Then, when a newline is received from the shell, a
search is made for the end of the prompt. If found, it will grab the first
word after the matched string and use it as the command name. If the com-
mand name begins with either '!', '%', or '^' screen will use the first
word on the following line (if found) in preference to the just-found name.
This helps csh users get better command names when using job control or
history recall commands.
Here's some .screenrc examples:
screen -t top 2 nice top
Adding this line to your .screenrc would start a nice-d version of the
"top" command in window 2 named "top" rather than "nice".
shelltitle '> |csh'
screen 1
These commands would start a shell with the given shelltitle. The title
specified is an auto-title that would expect the prompt and the typed com-
mand to look something like the following:
/usr/joe/src/dir> trn
(it looks after the '> ' for the command name). The window status would
show the name "trn" while the command was running, and revert to "csh" upon
completion.
bind R screen -t '% |root:' su
Having this command in your .screenrc would bind the key sequence "C-a R"
to the "su" command and give it an auto-title name of "root:". For this
auto-title to work, the screen could look something like this:
% !em
emacs file.c
Here the user typed the csh history command "!em" which ran the previously
entered "emacs" command. The window status would show "root:emacs" during
the execution of the command, and revert to simply "root:" at its comple-
tion.
bind o title
bind E title ""
bind u title (unknown)
The first binding doesn't have any arguments, so it would prompt you for a
title. when you type "C-a o". The second binding would clear an auto-
PROMPT_COMMAND:
PROMPT_COMMAND='echo -n -e "\033k\033\134"'
(I used "134" to output a `\' because of a bug in bash v1.04).
THE VIRTUAL TERMINAL
Each window in a screen session emulates a VT100 terminal, with some extra
functions added. The VT100 emulator is hardcoded, no other terminal types
can be emulated.
Usually screen tries to emulate as much of the VT100/ANSI standard as pos-
sible. 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. Notice that, however, on machines using the ter-
minfo database this variable has no effect. Furthermore, the variable
$WINDOW is set to the window number of each window.
The actual set of capabilities supported by the virtual terminal depends on
the capabilities supported by the physical terminal. If, for instance, the
physical terminal does not support underscore mode, screen does not put the
`us' and `ue' capabilities into the window's $TERMCAP variable, accord-
ingly. However, a minimum number of capabilities must be supported by a
terminal in order to run screen; namely scrolling, clear screen, and direct
cursor addressing (in addition, screen does not run on hardcopy terminals
or on terminals that over-strike).
Also, you can customize the $TERMCAP value used by screen by using the
"termcap" .screenrc command, or by defining the variable $SCREENCAP prior
to startup. When the is latter defined, its value will be copied verbatim
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.
Screen maintains a hardstatus line for every window. If a window gets
selected, the display's hardstatus will be updated to match the window's
hardstatus line. If the display has no hardstatus the line will be
displayed as a standard screen message. The hardstatus line can be changed
with the ANSI Application Program Command (APC): "ESC_<string>ESC\". As a
convenience for xterm users the sequence "ESC]0..2;<string>^G" is also
accepted.
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 dif-
ferent terminal, as the value of $TERMCAP cannot be modified by parent
processes.
The following is a list of control sequences recognized by screen. "(V)"
and "(A)" indicate VT100-specific and ANSI- or ISO-specific functions,
respectively.
ESC E Next Line
ESC D Index
ESC M Reverse Index
ESC H Horizontal Tab Set
ESC Z Send VT100 Identification String
ESC 7 (V) Save Cursor and Attributes
ESC 8 (V) Restore Cursor and Attributes
ESC [s (A) Save Cursor and Attributes
ESC > (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 interpre-
tation.
ESC _ (A) Application Program Command (Hardstatus)
ESC ] (A) Operating System Command (Hardstatus, xterm
title hack)
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
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
30 (A) Foreground Black
31 (A) Foreground Red
32 (A) Foreground Green
33 (A) Foreground Yellow
34 (A) Foreground Blue
35 (A) Foreground Magenta
36 (A) Foreground Cyan
37 (A) Foreground White
39 (A) Foreground Default
40 (A) Background Black
...
ESC [ Pn L (A) Insert Line
ESC [ Pn M (A) Delete Line
ESC [ Pn @ (A) Insert Character
ESC [ Pn P (A) Delete Character
ESC [ Pn S Scroll Scrolling Region Up
ESC [ Pn T Scroll Scrolling Region Down
ESC [ Ps ;...; Ps h Set Mode
ESC [ Ps ;...; Ps l Reset Mode
Ps = 4 (A) Insert Mode
20 (A) Automatic Linefeed Mode
34 Normal Cursor Visibility
?1 (V) Application Cursor Keys
?3 (V) Change Terminal Width to 132 columns
?5 (V) Reverse Video
?6 (V) Origin Mode
?7 (V) Wrap Mode
?25 (V) Visible Cursor
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 [ x Send Terminal Parameter Report
ESC [ > c Send VT220 Secondary Device Attributes String
ESC [ 6 n Send Cursor Position Report
Here is the table of the default key bindings. (A) means that the command
is executed if the keyboard is switched into application mode.
Key name Termcap name Command
______________________________________________________
Cursor up ku stuff \033[A
stuff \033OA (A)
Cursor down kd stuff \033[B
stuff \033OB (A)
Cursor right kr stuff \033[C
stuff \033OC (A)
Cursor left kl stuff \033[D
stuff \033OD (A)
Function key 0 k0 stuff \033[10~
Function key 1 k1 stuff \033OP
Function key 2 k2 stuff \033OQ
Function key 3 k3 stuff \033OR
Function key 4 k4 stuff \033OS
Function key 5 k5 stuff \033[15~
Function key 6 k6 stuff \033[17~
Function key 7 k7 stuff \033[18~
Function key 8 k8 stuff \033[19~
Function key 9 k9 stuff \033[20~
Function key 10 k; stuff \033[21~
Function key 11 F1 stuff \033[22~
Function key 12 F2 stuff \033[23~
Backspace kb stuff \010
Home kh stuff \033[1~
End kH stuff \033[4~
Insert kI stuff \033[2~
Delete kD stuff \033[3~
Page up kP stuff \033[5~
Page down kN stuff \033[6~
Keypad 0 f0 stuff 0
stuff \033Op (A)
Keypad 1 f1 stuff 1
stuff \033Oq (A)
Keypad 2 f2 stuff 2
stuff \033Or (A)
Keypad 3 f3 stuff 3
stuff \033Os (A)
Keypad 4 f4 stuff 4
stuff \033Ot (A)
Keypad 5 f5 stuff 5
stuff \033Ou (A)
Keypad 6 f6 stuff 6
stuff \033Ov (A)
Keypad 7 f7 stuff 7
stuff \033Ow (A)
Keypad 8 f8 stuff 8
stuff \033Ox (A)
Keypad 9 f9 stuff 9
stuff \033Ol (A)
Keypad enter fe stuff \015
stuff \033OM (A)
SPECIAL TERMINAL CAPABILITIES
The following table describes all terminal capabilities that are recognized
by screen and are not in the termcap(5) manual. You can place these capa-
bilities in your termcap entries (in `/etc/termcap') or use them with the
commands `termcap', `terminfo' and `termcapinfo' in your screenrc files. It
is often not possible to place these capabilities in the terminfo database.
LP (bool) Terminal has VT100 style margins (`magic margins'). Note that
this capability is obsolete because screen uses the standard
'xn' instead.
Z0 (str) Change width to 132 columns.
Z1 (str) Change width to 80 columns.
WS (str) Resize display. This capability has the desired width and
height as arguments. SunView(tm) example: '\E[8;%d;%dt'.
NF (bool) Terminal doesn't need flow control. Send ^S and ^Q direct to
the application. Same as 'flow off'. The opposite of this
capability is 'nx'.
G0 (bool) Terminal can deal with ISO 2022 font selection sequences.
S0 (str) Switch charset 'G0' to the specified charset. Default is
'\E(%.'.
E0 (str) Switch charset 'G0' back to standard charset. Default is
'\E(B'.
C0 (str) Use the string as a conversion table for font '0'. See the
'ac' capability for more details.
CS (str) Switch cursorkeys to application mode.
CE (str) Switch cursorkeys back to normal mode.
AN (bool) Turn on autonuke. See the 'autonuke' command for more details.
OL (num) Set the output buffer limit. See the 'obuflimit' command for
more details.
KJ (str) Set the kanji type of the terminal. Valid strings are "jis",
"euc" and "sjis".
AF (str) Change character forground color in an ANSI conform way. This
strings depending on the current font and terminal type. Use this feature
if you want to work with a common standard character set (say ISO8851-
latin1) even on terminals that scatter the more unusual characters over
several national language font pages.
Syntax:
XC=<charset-mapping>{,,<charset-mapping>}
<charset-mapping> := <designator><template>{,<mapping>}
<mapping> := <char-to-be-mapped><template-arg>
The things in braces may be repeated any number of times.
A <charset-mapping> tells screen how to map characters in font <designator>
('B': Ascii, 'A': UK, 'K': german, etc.) to strings. Every <mapping>
describes to what string a single character will be translated. A template
mechanism is used, as most of the time the codes have a lot in common (for
example strings to switch to and from another charset). Each occurence of
'%' in <template> gets substituted with the <template-arg> specified
together with the character. If your strings are not similar at all, then
use '%' as a template and place the full string in <template-arg>. A quot-
ing mechanism was added to make it possible to use a real '%'. The '\'
character quotes the special characters '\', '%', and ','.
Here is an example:
termcap hp700 'XC=B\E(K%\E(B,\304[,\326\\\\,\334]'
This tells screen, how to translate ISOlatin1 (charset 'B') upper case
umlaut characters on a hp700 terminal that has a german charset. '\304'
gets translated to '\E(K[\E(B' and so on. Note that this line gets parsed
*three* times before the internal lookup table is built, therefore a lot of
quoting is needed to create a single '\'.
Another extension was added to allow more emulation: If a mapping
translates the unquoted '%' char, it will be sent to the terminal whenever
screen switches to the corresponding <designator>. In this special case the
template is assumed to be just '%' because the charset switch sequence and
the character mappings normaly haven't much in common.
This example shows one use of the extension:
termcap xterm 'XC=K%,%\E(B,[\304,\\\\\326,]\334'
Here, a part of the german ('K') charset is emulated on an xterm. If
screen has to change to the 'K' charset, '\E(B' will be sent to the termi-
nal, i.e. the ASCII charset is used instead. The template is just '%', so
the mapping is straightforward: '[' to '\304', '\' to '\326', and ']' to
'\334'.
STY Alternate socket name.
SYSSCREENRC Alternate system screenrc file.
TERM Terminal name.
TERMCAP Terminal description.
FILES
$SYSSCREENRC
/local/etc/screenrc screen initialization commands
$ISCREENRC
$SCREENRC
$HOME/.iscreenrc
$HOME/.screenrc Read in after /local/etc/screenrc
$ISCREENDIR/S-<login>
$SCREENDIR/S-<login>
/local/screens/S-<login> Socket directories (default)
/usr/tmp/screens/S-<login> Alternate socket directories.
<socket directory>/.termcap Written by the "termcap" 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.
COPYLEFT
Copyright (C) 1993
Juergen Weigert (jnweiger@immd4.informatik.uni-erlangen.de)
Michael Schroeder (mlschroe@immd4.informatik.uni-erlangen.de)
Copyright (C) 1987 Oliver Laumann
This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the Free
Software Foundation; either version 2, or (at your option) any later ver-
sion.
This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FIT-
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 (mrgreen@mame.mu.oz.au),
Christopher Williams (cgw@unt.edu),
Matt Mosley (mattm@access.digex.net),
Gregory Neil Shapiro (gshapiro@wpi.WPI.EDU).
VERSION
This is version 3.7.0. 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.
BUGS
+ `dm' (delete mode) and `xs' are not handled correctly (they are
ignored). `xn' is treated as a magic-margin indicator.
+ Screen has no clue about double-high or double-wide characters. But
this is the only area where vttest is allowed to fail.
+ 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".
+ Entries in "/etc/utmp" are not removed when screen is killed with SIG-
KILL. This will cause some programs (like "w" or "rwho") to advertise
Created Tue Jan 30 22:40:32 CST 1996 by man2html