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, sev-
eral control functions from the ANSI X3.64 (ISO 6429) and
ISO 2022 standards (e.g. insert/delete line and support
for multiple character sets). There is a scrollback his-
tory buffer for each virtual terminal and a copy-and-paste
mechanism that allows moving text regions between windows.
When 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 win-
dows, turn output logging on and off, copy-and-paste text
between windows, view the scrollback history, switch
between windows in whatever manner you wish, etc. When a
program terminates, screen (per default) kills the window
that contained it. If this window was in the foreground,
the display switches to the previous window; if none are
left, screen exits.
Everything you type is sent to the program running in the
current window. The only exception to this is the one
keystroke that is used to initiate a command to the window
manager. By default, each command begins with a control-a
(abbreviated C-a from now on), and is followed by one
other keystroke. The command character and all the key
bindings can be fully customized to be anything you like,
though they are always two characters in length.
The standard way to create a new window is to type "C-a
c". This creates a new window running a shell and
switches to that window immediately, regardless of the
state of the process running in the current window. Simi-
larly, you can create a new window with a custom command
in it by first binding the command to a keystroke (in your
.screenrc file or at the "C-a :" command line) and then
using it just like the "C-a c" command. In addition, new
from a shell prompt within a previously created window.
This will not run another copy of screen, but will instead
supply the command name and its arguments to the window
manager (specified in the $STY environment variable) who
will use it to create the new window. The above example
would start the emacs editor (editing prog.c) and switch
to its window.
If "/etc/utmp" is writable by screen, an appropriate
record will be written to this file for each window, and
removed when the window is terminated. This is useful for
working with "talk", "script", "shutdown", "rsend", "sccs"
and other similar programs that use the utmp file to
determine who you are. As long as screen is active on your
terminal, the terminal's own record is removed from the
utmp file. See also "C-a L".
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 for example.)
If you're impatient and want to get started without doing
a lot more reading, you should remember this one command:
"C-a ?". Typing these two characters will display a list
of the available screen commands and their bindings. Each
keystroke is discussed in the section "DEFAULT KEY 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 mar-
gins 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 per-
fectly 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 capability.
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
current terminal. By default, screen tries to
restore its old window sizes when attaching to resiz-
able 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 session. It has the same effect as
typing "C-a d" from screen's controlling terminal. -D
is the equivalent to the power detach key. If no
session can be detached, this option is ignored. The
combination "screen -D -r" can be used to `transport'
the elsewhere running session to this terminal and
logout there. Note: It is a good idea to have the
status of your sessions checked by means of "screen
-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". When creating a screen session, this option
sets the default command character. In a multiuser
session all users added will start off with this com-
mand character. But when attaching to an already run-
ning session, this option changes only the command
character of the attaching user. This option is
equivalent to either the commands "defescape" or
"escape" respectively.
-f, -fn, and -fa
turns flow-control on, off, or "automatic switching
mode". This can also be defined through the "def-
flow" .screenrc command.
-h num
Specifies the history scrollback buffer to be num
lines high.
is on. See the "defflow" .screenrc command for
details. The use of this option is discouraged.
-l and -ln
turns login mode on or off (for /etc/utmp updating).
This can also be defined through the "deflogin"
.screenrc command.
-ls and -list
does not start screen, but prints a list of
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.
-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.
-m causes screen to ignore the $STY environment vari-
able. 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 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 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.
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.
-t name
sets the title (a.k.a.) for the default shell or
specified program. See also the "shelltitle"
.screenrc command.
-v Print version number.
-wipe
does the same as "screen -ls", but removes destroyed
sessions instead of marking them as `dead'.
-x Attach to a not detached screen session. (Multi dis-
play mode).
DEFAULT KEY BINDINGS
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. 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 num-
ber to switch to.
C-a 0 (select 0)
... ...
C-a 9 (select 9) Switch to window number 0 - 9.
C-a C-a (other) Toggle to the window displayed
previously. Note that this
binding defaults to the command
character typed twice, unless
overridden; for instance, if you
use the option "-e]x", this com-
mand becomes "]]", not "]C-a".
C-a a (meta) Send the command character (C-a)
to window. See escape command.
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 termi-
nal.
C-a D D (pow_detach) Detach and logout.
C-a f
C-a C-f (flow) Toggle flow on, off or auto.
C-a C-g (vbell) Toggles screen's visual bell
mode.
C-a h (hardcopy) Write a hardcopy of the current
window to the file "hardcopy.n".
C-a H (log) Begins/ends logging of the cur-
rent window to the file "screen-
log.n".
C-a i
C-a C-i (info) Show info about this window.
C-a k
C-a C-k (kill) Destroy current window.
C-a l
C-a C-l (redisplay) Fully refresh current window.
C-a L (login) Toggle this windows login slot.
Available only if screen is con-
figured to update the utmp
database.
C-a m
C-a C-m (lastmsg) Repeat the last message dis-
played in the message line.
C-a M (monitor) Toggles monitoring of the cur-
C-a n
C-a C-n (next) Switch to the next window.
C-a N (number) Show the number (and title) of
the current window.
C-a backspace
C-a h
C-a p
C-a C-p (prev) Switch to the previous window
(opposite of C-a n).
C-a q
C-a C-q (xon) Send a control-q to the current
window.
C-a r
C-a C-r (wrap) Toggle the current window's
line-wrap setting (turn the cur-
rent 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 compila-
tion 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-con-
trol.
C-a Z (reset) Reset the virtual terminal to
its "power-on" values.
C-a . (dumptermcap) Write out a ".termcap" file.
screen.
C-a : (colon) Enter command line mode.
C-a [
C-a C-[
C-a esc (copy) Enter copy/scrollback mode.
C-a ] (paste .) Write the contents of the paste
buffer to the stdin queue of the
current window.
C-a {
C-a } (history) Copy and paste a previous (com-
mand) 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 cur-
rent 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 com-
mands from the files "/usr/local/etc/screenrc" and
".screenrc" in the user's home directory. These are the
"programmer's defaults" that can be overridden in the fol-
lowing ways: for the global screenrc file screen searches
for the environment variable $SYSSCREENRC (this override
feature may be disabled at compile-time). The user spe-
cific screenrc file is searched in $ISCREENRC, then
$SCREENRC, then $HOME/.iscreenrc and finally defaults to
$HOME/.screenrc. The command line option -c takes prece-
functions to keys, and to automatically establish one or
more windows at the beginning of your screen session.
Commands are listed one per line, with empty lines being
ignored. A command's arguments are separated by tabs or
spaces, and may be surrounded by single or double quotes.
A `#' turns the rest of the line into a comment, except in
quotes. Unintelligible lines are warned about and
ignored. Commands may contain references to environment
variables. The syntax is the shell-like "$VAR " or
"${VAR}". Note that this causes incompatibility with pre-
vious screen versions, as now the '$'-character has to be
protected with '\' if no variable substitution shall be
performed. A string in single-quotes is also protected
from variable substitution.
Customization can also be done 'on-line'. To enter the
command mode type `C-a :'. Note that commands starting
with "def" change default values, while others change cur-
rent settings.
The following commands are available:
acladd usernames
Enable users to fully access this screen session. User-
names can be one user or a comma seperated list of users.
This command enables to attach to the screen session and
performs the equivalent of `aclchg usernames +rwx "#?"'.
executed. To add a user with restricted access, use the
`aclchg' command below. Multi user mode only.
aclchg usernames permbits list
Change permissions for a comma seperated list of users.
Permission bits are represented as `r', `w' and `x'. Pre-
fixing `+' 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 com-
mands. if usernames consists of a single `*', 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 cur-
rently 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
Remove a user from screen's access control list. If cur-
rently 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 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).
allpartial on|off
If set to on, only the current cursor line is refreshed on
window change. This affects all windows and is useful for
slow terminal lines. The previous setting of full/partial
refresh for each window is restored with "allpartial off".
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 win-
dows.
at [identifier][#|*|%] command [args ... ]
Execute a command at other displays or windows as if it
had been entered there. "At" changes the context (the
`current window' or `current display' setting) of the com-
mand. If the first parameter describes a non-unique con-
text, the command will be executed multiple times. If the
first parameter is of the form `identifier*' then identi-
fier is matched against user names. The command is exe-
cuted once for each display of the selected user(s). If
the first parameter is of the form `identifier%' identi-
fier is matched against displays. Displays are named after
the ttys they attach. The prefix `/dev/' or `/dev/tty' may
be omitted from the identifier. If identifier has a `#'
or nothing appended it is matched against window numbers
and titles. Omitting an identifier in front of the `#',
`*' or `%'-character selects all users, displays or win-
dows because a prefix-match is performed. Note that on the
the affected display(s), not for the initiator of the `at'
command.
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 indi-
cated in the "DEFAULT KEY BINDINGS" section, e.g. the com-
mand to create a new window is bound to "C-c" and "c".
The "bind" command can be used to redefine the key bind-
ings and to define new bindings. The key argument is
either a single character, a two-character sequence of the
form "^x" (meaning "C-x"), a backslash followed by an
octal number (specifying the ASCII code of the character),
or a backslash followed by a second character, such as
"\^" or "\\". The argument can also be quoted, if you
like. If no further argument is given, any previously
established binding for this key is removed. The command
argument can be any command listed in this section.
Some examples:
bind \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.
bindkey [-d] [-m] [-a] [[-k|-t] string [cmd args]]
This command manages screen's input translation tables.
Every entry in one of the tables tells screen how to react
if a certain sequence of characters is encountered. There
are three tables: one that should contain actions pro-
grammed by the user, one for the default actions used for
terminal emulation and one for screen's copy mode to do
cursor movement. See section "INPUT TRANSLATION" for a
list of default key bindings.
If the -d option is given, bindkey modifies the default
table, -m changes the copy mode table and with neither
option the user table is selected. The argument string is
the sequence of characters to which an action is bound.
This can either be a fixed string or a termcap keyboard
capability name (selectable with the -k option).
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 tim-
ing. One cannot turn off the timing if a termcap capabilty
is used.
Cmd can be any of screen's commands with an arbitrary num-
ber 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
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 win-
dow. Most useful if a character device is attached to the
window rather than a shell process.
bufferfile [exchange-file]
Change the filename used for reading and writing with the
paste buffer. If the optional argument to the "buffer-
file" 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 characters between 128 and 159 as control func-
tions. Such an 8-bit code is normally the same as ESC
followed by the corresponding 7-bit code. The default set-
ting is to process c1 codes and can be changed with the
"defc1" command. Users with fonts that have usable char-
acters in the c1 positions may want to turn this off.
charset set
Change the current character set slot designation and
charset mapping. The first four character of set are
treated as charset designators while the fifth and sixth
character must be in range '0' to '3' and set the GL/GR
charset mapping. On every position a '.' may be used to
indicate that the corresponding charset/mapping should not
be changed (set is padded to six 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.
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.
clear
Clears the current window and saves its image to the
scrollback buffer.
colon [prefix]
Allows you to enter ".screenrc" command lines. Useful for
on-the-fly modification of key bindings, specific window
creation and changing settings. Note that the "set" key-
word no longer exists! Usually commands affect the current
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
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 specified
amount of lines while preserving the cursor position.
(Default: half screen-full).
C-b and C-f scroll the display up/down a full screen.
g moves to the beginning of the buffer.
% jumps to the specified percentage of the buffer.
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 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,
"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 sepa-
rated by a newline character (012), lines glued seam-
less, lines separated by a single whitespace. Note
that you can prepend the newline character with a car-
riage return character, by issuing a "crlf on".
v is for all the vi users with ":set numbers" - it tog-
gles 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 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 posi-
tion. You can use this to adjust an already placed
mark.
@ does nothing. Does not even exit copy mode.
All keys not described here exit copy mode.
copy_reg [key]
No longer exists, use "readreg" instead.
crlf on|off
This affects the copying of text regions with the `C-a ['
command. If it is set to `on', lines will be separated by
the two character sequence `CR' - `LF'. Otherwise
(default) only `LF' is used.
debug on|off
Turns runtime debugging on or off. If screen has been com-
piled with option -DDEBUG debugging available and is
turned on per default. Note that this command only affects
debugging output from the main "SCREEN" process.
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
`off'. Note that you can use the special `AN' terminal
capability if you want to have a dependency on the termi-
nal 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 "defescape" 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 generated hardstatus lines
impossible. If the parameter status is omitted, the cur-
rent default string is displayed. Per default the hard-
status line of new windows is empty.
defkanji jis|sjis|euc
Same as the kanji command except that the default setting
for new windows is changed. Initial setting is `off', i.e.
`jis'.
deflogin on|off
as distributed (see config.h.in).
defmode mode
The mode of each newly allocated pseudo-tty is set to
mode. Mode is an octal number. When no "defmode" command
is given, mode 0622 is used.
defmonitor on|off
Same as the monitor command except that the default set-
ting for new windows is changed. Initial setting is `off'.
defobuflimit limit
Same as the obuflimit command except that the default set-
ting for new displays is changed. Initial setting is 256
bytes. Note that you can use the special 'OL' terminal
capability if you want to have a dependency on the termi-
nal type.
defscrollback num
Same as the scrollback command except that the default
setting for new windows is changed. Initial setting is
100.
defwrap on|off
Same as the wrap command except that the default setting
for new windows is changed. Initially line-wrap is on and
can be toggled with the "wrap" command ("C-a r") or by
means of "C-a : wrap on|off".
defwritelock on|off|auto
Same as the writelock command except that the default set-
ting for new windows 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".)
This command prompts the user for a digraph sequence. The
next two characters 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
'"'" enables the user to generate an a-umlaut by typing
CTRL-K a.
dumptermcap
Write the termcap entry for the virtual terminal optimized
for the currently active window to the file ".termcap" in
the user's "$HOME/.screen" directory (or wherever screen
stores its sockets. See the "FILES" section below). This
termcap entry is identical to the value of the environment
variable $TERMCAP that is set up by screen for each win-
dow. For terminfo based systems you will need to run a
converter like captoinfo and then compile the entry with
tic.
echo [-n] message
The echo command may be used to annoy screen users with a
'message of the day'. Typically installed in a global
/local/etc/screenrc. See also "sleep". Echo is also use-
ful 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".
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 pattern fdpat. This
pattern is basically a three character sequence represent-
ing stdin, stdout and stderr of newcommand. A dot (.) con-
nects the file descriptor to screen. An exclamation mark
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 com-
mand can be omitted. Trailing dots and a fdpat consisting
only of dots can be omitted. A simple `|' is synonymous
for the pattern `!..|'; the word exec can be omitted 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 origi-
nal shell is still running. Output of both shells is dis-
played and user input is sent to the new /bin/sh.
exec !.. stty 19200
exec ! stty 19200
!!stty 19200
Set the speed of the window's tty. If your stty command
operates on stdout, then add another `!'.
exec !..| less
|less
This adds a pager to the window output. The special char-
acter `|' is needed to give the user control over the
pager although it gets its input from the window's pro-
cess. This works, because less listens on stderr (a behav-
ior that screen would not expect without the `|') when its
stdin is not a tty. Less versions newer than 177 fail
miserably here; good old pg still works.
!:sed -n s/.*Error.*/\007/p
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 dis-
cussion on "FLOW-CONTROL" later on in this document for
full details and note, that this is subject to change in
future releases. Default is set by `defflow'.
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 hard-
copy.n in the window's default directory, where n is the
number of the current window. This either appends or
overwrites the file if it exists. See below.
hardcopy_append on|off
If set to "on", screen will append to the "hardcopy.n"
files created by the command "C-a h", otherwise these
files are overwritten each time. Default is `off'.
hardcopydir directory
Defines a directory where hardcopy files will be placed.
If unset, hardcopys are dumped in 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 messages are overlayed in
reverse video mode at the display line. Note that the
hardstatus feature can only be used if the termcap/ter-
minfo capabilities "hs", "ts", "fs" and "ds" are set prop-
erly. Default is `on' whenever the "hs" capability is pre-
sent.
Set the display height to a specified number of lines.
When no argument is given it toggles between 24 and 42
lines display.
help
Not really a online help, but displays a help screen show-
ing you all the key bindings. The first pages list all
the internal commands followed by their current bindings.
Subsequent pages will display the custom commands, one
command per key. Press space when you're done reading
each page, or return to exit early. All other characters
are ignored. See also "DEFAULT KEY BINDINGS" section.
history
Usually users work with a shell that allows easy access to
previous commands. For example csh has the command "!!"
to repeat the last command executed. Screen allows you to
have a primitive way of re-calling "the command that
started ...": You just type the first letter of that com-
mand, 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 "(col-
umn,row)" starting with "(1,1)", the terminal width and
height plus the size of the scrollback buffer in lines,
like in "(80,24)+50", various flag settings (flow-control,
insert mode, origin mode, wrap mode, application-keypad
mode, output logging, activity monitoring and redraw (`+'
indicates enabled, `-' not)), the currently active charac-
ter set (G0, G1, G2, or G3), and in square brackets the
terminal character sets that are currently designated as
G0 through G3. For system information use the "time" com-
mand.
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
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 process (shell) running in the window
receives a HANGUP condition, the window structure is
removed and screen switches to the previously displayed
window. When the last window is destroyed, screen exits.
Note: Emacs users should keep this command in mind, when
killing a line. It is recommended not to use "C-a" as the
screen escape key or to rebind kill to "C-a K".
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 com-
mands "msgwait" and "msgminwait" for fine tuning.
license
Display the disclaimer page. This is done whenever screen
is started without options, which should be often enough.
See also the "startup_message" command.
lockscreen
Lock this display. Call a screenlock program
(/local/bin/lck or /usr/bin/lock or a builtin if no other
is available). Screen does not accept any command keys
until this program terminates. Meanwhile processes in the
windows may continue, as the windows are in the `detached'
state. The screenlock program may be changed through the
environment variable $LOCKPRG (which must be set in the
shell from which screen is started) and is executed with
the user's uid and gid.
log [on|off]
Start/stop writing output of the current window to a file
"screenlog.n" in the window's default directory, where n
is the number of the current window. This filename can be
changed with the `logfile' command. If no parameter is
given, the state of logging is toggled. The session log is
appended to the previous contents of the file if it
already exists. The current contents and the contents of
the scrollback history are not included in the session
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 con-
fig.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 sup-
port.
mapdefault
Tell screen that the next input character should only be
looked up in the default bindkey table. See also "bind-
key".
mapnotnext
Like mapdefault, but don't even look in the default bind-
key 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/his-
tory 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.
meta
Insert the command character (C-a) in the current window's
input stream.
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 a new message when one mes-
sage 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 com-
mands `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]
dows. The default value is 256. If you have a fast display
(like xterm), you can set it to some higher value. If no
argument is specified, the current setting is displayed.
other
Switch to the window displayed previously.
partial on|off
Defines whether the display should be refreshed (as with
redisplay) after switching to the current window. This
command only affects the current window. To immediately
affect all windows use the allpartial command. Default is
`off', of course. This default is fixed, as there is cur-
rently no defpartial command.
password [crypted_pw]
Present a crypted password in your ".screenrc" file and
screen will ask for it, whenever someone attempts to
resume a detached. This is useful if you have privileged
programs running under screen and you want to protect your
session from reattach attempts by another user masquerad-
ing as your uid (i.e. any superuser.) If no crypted pass-
word is specified, screen prompts twice for typing a pass-
word and places its encryption in the paste buffer.
Default is `none', this disables password checking.
paste [registers [dest_reg]]
Write the (concatenated) contents of the specified regis-
ters to the stdin queue of the current window. The regis-
ter '.' 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
readbuf 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 reg-
isters is pasted into the named destination register
rather than the window. If '.' is used as the second argu-
ment, 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
pow_break
Reopen the window's terminal line and send a break condi-
tion. 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 performed. 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 capabilities "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 >
/tmp/scrprint'". printcmd without a command displays the
current setting. The ansi sequence ESC \ ends printing
and closes the pipe.
Warning: Be careful with this command! If other user have
write access to your terminal, they will be able to fire
off print commands.
process [key]
Stuff the contents of the specified register into screen's
input queue. If no argument is given you are prompted for
a register name. The text is parsed as if it had been
typed in from the user's keyboard. This command can be
used to bind multiple actions to a single key.
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
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 contents of
the named file into the register, just as readbuf reads
the screen-exchange file into the paste buffer. The fol-
lowing 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 redis-
play when in partial redraw mode.
register key string
Save the specified string to the register key. See also
the "paste" command.
removebuf
Unlinks the screen-exchange file used by the commands
"writebuf" and "readbuf".
reset
Reset the virtual terminal to its "power-on" values. Use-
ful when strange settings (like scroll regions or graphics
character set) are left over from an application.
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-
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 title "foobar" in window #2). Note,
that unlike previous versions of screen no additional
default window is created when "screen" commands are
included in your ".screenrc" file. When the initialization
is completed, screen switches to the last window specified
in your .screenrc file or, if none, opens a default window
#0.
scrollback num
Set the size of the scrollback buffer for the current win-
dows 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 num-
ber 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 win-
dows 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 constructed from the tty and host names.
setenv [var [string]]
Set the environment variable var to value string. If only
var is specified, the user will be prompted to enter a
value. If no parameters are specified, the user will be
prompted for both variable and value. The environment is
inherited by all subsequently forked shells.
Set the command to be used to create a new shell. This
overrides the value of the environment variable $SHELL.
This is useful if you'd like to run a tty-enhancer which
is expecting to execute the program specified in $SHELL.
If the command begins with a '-' character, the shell will
be started as a login-shell.
shelltitle title
Set the title for all shells created during startup or by
the C-A C-c command. For details about what a title is,
see the discussion entitled "TITLES (naming windows)".
silence [on|off|sec]
Toggles silence monitoring of windows. When silence is
turned on and an affected window is switched into the
background, you will receive the silence notification mes-
sage in the status line after a specified period of inac-
tivity (silence). The default timeout can be changed with
the `silencewait' command or by specifying a number of
seconds instead of `on' or `off'. Silence is initially
off for all windows.
silencewait sec
Define the time that all windows monitored for silence
should wait before displaying a message. Default 30 sec-
onds.
sleep num
This command will pause the execution of a .screenrc file
for num seconds. Keyboard activity will end the sleep.
It may be used to give users a chance to read the messages
output by "echo".
slowpaste usec
Define the speed at which text is inserted by the paste
("C-a ]") command. If the slowpaste value is nonzero text
is written character by character. screen will make a
pause of usec milliseconds after each single character
write to allow the application to process its input. Only
use slowpaste if your underlying system exposes flow con-
trol problems while pasting large amounts of text.
sorendition [attr [color]]
Change the way screen does highlighting for text marking
and printing messages. Attr is a hexadecimal number and
forground/background of the highlighted text. Some knowl-
edge 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 vari-
able is set to "screen" by default. But when no descrip-
tion for "screen" is installed in the local termcap or
terminfo data base, you set $TERM to - say - "vt100". This
won't do much harm, as 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 and resetting the
default.
termcap term terminal-tweaks [window-tweaks]
terminfo term terminal-tweaks [window-tweaks]
termcapinfo 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
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. Two sepa-
rate commands are provided, as there are subtle syntactic
differences, e.g. when parameter interpolation (using `%')
is required. Note that termcap names of the capabilities
minfo and termcap syntax, you can use the command `term-
capinfo', which is just a shorthand for a pair of `term-
cap' and `terminfo' commands with identical arguments.
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
(am@) and enables the insert mode (im) and end-insert (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 $SCREENCAP variable
prior to running screen. See the discussion on the "VIR-
TUAL TERMINAL" in this manual, and the termcap(5) man page
for more information on termcap definitions.
time
Uses the message line to display the time of day, the host
name, and the load averages over 1, 5, and 15 minutes (if
this is available on your system). For window specific
information use "info".
title [windowalias]
Set the name of the current window to windowalias. If no
name is specified, screen prompts for one. This command
was known as `aka' in previous releases.
unsetenv var
Unset an environment variable.
vbell on|off
If your terminal does not support a visual bell, a `vbell-
message' is displayed in the status line. Sets the visual
bell setting for this window. If your terminal does not
support a visual bell, a `vbell-message' is displayed in
the status line. Refer to the termcap variable `vb' (ter-
minfo: 'flash').
vbell_msg message
Sets the visual bell message. message is printed to the
status line if the window receives a bell character (^G)
and vbell is set to "on". The default message is "Wuff,
Wuff!!".
vbellwait sec
Define a delay in seconds after each display of screen's
visual bell message. The default is 1 second.
Print the current version and the compile date in the sta-
tus line.
wall message
Write a message to all displays. The message will appear
in the terminal's status line.
width [num]
Toggle the window width between 80 and 132 columns or set
it to num columns if an argument is specified. This
requires a capable terminal and the termcap entries "Z0"
and "Z1". See the "termcap" command for more information.
windows
Uses the message line to display a list of all the win-
dows. Each window is listed by number with the name of
process that has been started in the window (or its
title); the current window is marked with a `*'; the pre-
vious window is marked with a `-'; all the windows that
are "logged in" are marked with a `$'; a background window
that has received a bell is marked with a `!'; a back-
ground window that is being monitored and has had activity
occur is marked with an `@'; a window which has output
logging turned on is marked with `(L)'; windows occupied
by other users are marked with `&'; windows in the zombie
state are marked with `Z'. If this list is too long to
fit on the terminal's status line only the portion around
the current window is displayed.
wrap [on|off]
Sets the line-wrap setting for the current window. When
line-wrap is on, the second consecutive printable charac-
ter output at the last column of a line will wrap to the
start of the following line. As an added feature,
backspace (^H) will also wrap through the left margin to
the previous line. Default is `on'.
writebuf
Writes the contents of the paste buffer to a public acces-
sible screen-exchange file. This is thought of as a primi-
tive means of communication between screen users on the
same host. The filename can be set with the bufferfile
command and defaults to "/tmp/screen-exchange".
writelock [on|off|auto]
writelock is in `auto' mode and grants exclusive input
permission to the user who is the first to switch to the
particular window. When he leaves the window, other users
may obtain the writelock (automatically). The writelock of
the current window is disabled by the command "writelock
off". If the user issues the command "writelock on" he
keeps the exclusive write permission while switching to
other windows.
xoff
xon
Insert a CTRL-s / CTRL-q character to the stdin queue of
the current window.
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 com-
mand, `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 win-
dows disappear when their process exits.
As the zombie-setting is manipulated globally for all win-
dows, this command should only be called defzombie. Until
we need this as a per window setting, the commands zombie
and defzombie are synonymous.
THE MESSAGE LINE
Screen displays informational messages and other diagnos-
tics in a message line. While this line is distributed to
appear at the bottom of the screen, it can be defined to
appear at the top of the screen during compilation. If
your terminal has a status line defined in its termcap,
screen will use this for displaying its messages, other-
wise a line of the current screen will be temporarily
overwritten and output will be momentarily interrupted.
The message line is automatically removed after a few sec-
onds delay, but it can also be removed early (on terminals
without a status line) by beginning to type.
The message line facility can be used by an application
running in the current window by means of the ANSI Privacy
message control sequence. For instance, from within the
DOW'<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 "defflow" .screenrc command.
Per default the windows are set to automatic flow-switch-
ing. 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
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
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.
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 dis-
played is the actual command name of the program created
in the window. However, it is sometimes useful to distin-
guish various programs of the same name or to change the
name on-the-fly to reflect the current state of the win-
dow.
The default name for all shell windows can be set with the
"shelltitle" command in the .screenrc file, while all
other windows are created with a "screen" command and thus
can have their name set with the -t option. Interac-
tively, there is the title-string escape-sequence
(<esc>kname<esc>\) and the "title" command (C-a A). The
former can be output from an application to control the
window's name under software control, and the latter will
prompt for a name when typed. You can also bind pre-
defined names to keys with the "title" command to set
things quickly without prompting.
Finally, screen has a shell-specific heuristic that is
enabled by setting the window's name to "search|name" and
arranging to have a null title escape-sequence output as a
part of your prompt. The search portion specifies an end-
of-prompt search string, while the name portion specifies
the default shell name for the window. If the name ends
in a `:' screen will add what it believes to be the 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 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 por-
tion 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
name. If the command name begins with either '!', '%', or
'^' screen will use the first word on the following line
(if found) in preference to the just-found name. This
helps csh users get better command names when using job
control or history recall commands.
Here's some .screenrc examples:
screen -t top 2 nice top
Adding this line to your .screenrc would start a nice-d
version of the "top" command in window 2 named "top"
rather than "nice".
shelltitle '> |csh'
screen 1
These commands would start a shell with the given shellti-
tle. The title specified is an auto-title that would
expect the prompt and the typed command to look something
like the following:
/usr/joe/src/dir> trn
(it looks after the '> ' for the command name). The win-
dow status would show the name "trn" while the command was
running, and revert to "csh" upon completion.
bind R screen -t '% |root:' su
Having this command in your .screenrc would bind the key
sequence "C-a R" to the "su" command and give it an auto-
title name of "root:". For this auto-title to work, the
screen could look something like this:
% !em
emacs file.c
Here the user typed the csh history command "!em" which
ran the previously entered "emacs" command. The window
status would show "root:emacs" during the execution of the
command, and revert to simply "root:" at its completion.
bind o title
bind E title ""
bind u title (unknown)
The first binding doesn't have any arguments, so it would
prompt you for a title. when you type "C-a o". The second
binding would clear an auto-title's current setting (C-a
E). The third binding would set the current window's
title to "(unknown)" (C-a u).
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 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 possible. But if your terminal lacks certain
capabilities, the emulation may not be complete. In these
cases screen has to tell the applications that some of the
features are missing. This is no problem on machines using
termcap, because screen can use the $TERMCAP variable to
customize the standard screen termcap.
But if you do a rlogin on another machine or your machine
supports only terminfo this method fails. Because of this,
screen offers a way to deal with these cases. Here is how
it works:
When screen tries to figure out a terminal name for
itself, it first looks for an entry named "screen.<term>",
where <term> is the contents of your $TERM variable. If
no such entry exists, screen tries "screen" (or "screen-w"
if the terminal is wide (132 cols or more)). If even this
entry cannot be found, "vt100" is used as a substitute.
The idea is that if you have a terminal which doesn't 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 variable reflecting the capabilities of the vir-
tual terminal emulated. Notice that, however, on machines
using the terminfo database this variable has no effect.
Furthermore, the variable $WINDOW is set to the window
number of each window.
The actual set of capabilities supported by the virtual
terminal depends on the capabilities supported by the
physical terminal. If, for instance, the physical termi-
nal does not support underscore mode, 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 is
latter defined, its value will be copied verbatim into
each window's $TERMCAP variable. This can either be the
full terminal definition, or a filename where the terminal
"screen" (and/or "screen-w") is defined.
Note that screen honors the "terminfo" .screenrc command
if the system uses the terminfo database rather than 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
printer port is enabled and disabled again for each chunk
of output). As a side-effect, programs running in differ-
ent 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 dis-
play 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 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 Z Send VT100 Identification
String
ESC 7 (V) Save Cursor and Attributes
ESC 8 (V) Restore Cursor and Attributes
ESC [s (A) Save Cursor and Attributes
ESC [u (A) Restore Cursor and Attributes
ESC c Reset to Initial State
ESC g Visual Bell
7 Visible
ESC = (V) Application Keypad Mode
ESC > (V) Numeric Keypad Mode
ESC # 8 (V) Fill Screen with E's
ESC \ (A) String Terminator
ESC ^ (A) Privacy Message String (Message
Line)
ESC ! Global Message String (Message
Line)
ESC k A.k.a. Definition String
ESC P (A) Device Control String. Outputs
a string directly to the host
terminal without interpreta-
tion.
ESC _ (A) Application Program Command
(Hardstatus)
ESC ] (A) Operating System Command (Hard-
status, 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
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 Cur-
sor
2 Entire Line
ESC [ Pn A Cursor Up
ESC [ Pn B Cursor Down
ESC [ Pn C Cursor Right
ESC [ Pn D Cursor Left
ESC [ Ps ;...; Ps m Select Graphic Rendition
Ps = None or 0 Default Rendition
1 Bold
2 (A) Faint
3 (A) Standout Mode (ANSI: Itali-
cized)
4 Underlined
5 Blinking
7 Negative Image
22 (A) Normal Intensity
23 (A) Standout Mode off (ANSI: Itali-
cized off)
24 (A) Not Underlined
25 (A) Not Blinking
27 (A) Positive Image
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
...
49 (A) Background Default
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 [ 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
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 spe-
cial)
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
INPUT TRANSLATION
In order to do a full VT100 emulation screen has to detect
that a sequence of characters in the input stream was gen-
erated by a keypress on the user's keyboard and insert the
VT100 style escape sequence. Screen has a very flexible
way of doing this by making it posible to map arbitrary
commands on arbitrary sequences of characters. For stan-
dard VT100 emulation the command will always insert a
string in the input buffer of the window (see also command
stuff in the command table). Because the sequences gener-
ated by a keypress can change after a reattach from a dif-
ferent terminal type, it is possible to bind commands to
the termcap name of the keys. Screen will insert the cor-
rect binding after each reattach. See the bindkey command
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 \033Ok (A)
Keypad - f- stuff -
stuff \033Om (A)
Keypad * f* stuff *
stuff \033Oj (A)
Keypad / f/ stuff /
stuff \033Oo (A)
Keypad = fq stuff =
stuff \033OX (A)
Keypad . f. stuff .
stuff \033On (A)
Keypad , f, stuff ,
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 term-
cap(5) manual. You can place these capabilities 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 mar-
gins'). 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. Sun-
View(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 selec-
tion sequences.
S0 (str) Switch charset 'G0' to the specified charset.
Default is '\E(%.'.
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 'obu-
flimit' 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 capability will almost
always be set to '\E[3%dm' ('\E[3%p1%dm' on
terminfo machines).
AB (str) Same as 'AF', but change background color.
AX (bool) Does understand ANSI set default fg/bg color
(\E[39m / \E[49m).
XC (str) Describe a translation of characters to
strings depending on the current font. More
details follow in the next section.
CHARACTER TRANSLATION
Screen has a powerful mechanism to translate characters to
arbitrary strings depending on the current font and termi-
nal 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
charset). Each occurence of '%' in <template> gets substi-
tuted 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 <tem-
plate-arg>. A quoting mechanism was added to make it pos-
sible to use a real '%'. The '\' character quotes the spe-
cial 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 corre-
sponding <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 terminal, i.e. the ASCII charset is
used instead. The template is just '%', so the mapping is
straightforward: '[' to '\304', '\' to '\326', and ']' to
'\334'.
ENVIRONMENT
COLUMNS Number of columns on the terminal (over-
rides termcap entry).
HOME Directory in which to look for .screenrc.
ISCREENRC Alternate user screenrc file.
LINES Number of lines on the terminal (overrides
termcap entry).
LOCKPRG Screen lock program.
NETHACKOPTIONS Turns on nethack option.
PATH Used for locating programs to run.
SCREENCAP For customizing a terminal's TERMCAP value.
SCREENDIR Alternate socket directory.
(default "/bin/sh").
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" out-
put function
/usr/tmp/screens/screen-exchange
or
/tmp/screen-exchange screen `interprocess communi-
cation 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;
useful, but WITHOUT ANY WARRANTY; without even the implied
warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the GNU General Public License for more
details.
You should have received a copy of the GNU General Public
License along with this program (see the file COPYING); if
not, write to the Free Software Foundation, Inc., 59 Tem-
ple Place - Suite 330, Boston, MA 02111-1307, USA
CONTRIBUTORS
Ken Beal (kbeal@amber.ssd.csd.harris.com),
Rudolf Koenig (rfkoenig@immd4.informatik.uni-erlangen.de),
Toerless Eckert (eckert@immd4.informatik.uni-erlangen.de),
Wayne Davison (davison@borland.com),
Patrick Wolfe (pat@kai.com, kailand!pat),
Bart Schaefer (schaefer@cse.ogi.edu),
Nathan Glasser (nathan@brokaw.lcs.mit.edu),
Larry W. Virden (lvirden@cas.org),
Howard Chu (hyc@hanauma.jpl.nasa.gov),
Tim MacKenzie (tym@dibbler.cs.monash.edu.au),
Markku Jarvinen (mta@{cc,cs,ee}.tut.fi),
Marc Boucher (marc@CAM.ORG),
Doug Siebert (dsiebert@isca.uiowa.edu),
Ken Stillson (stillson@tsfsrv.mitre.org),
Ian Frechett (frechett@spot.Colorado.EDU),
Brian Koehmstedt (bpk@gnu.ai.mit.edu),
Don Smith (djs6015@ultb.isc.rit.edu),
Frank van der Linden (vdlinden@fwi.uva.nl),
Martin Schweikert (schweik@cpp.ob.open.de),
David Vrona (dave@sashimi.lcu.com),
E. Tye McQueen (tye%spillman.UUCP@uunet.uu.net),
Matthew Green (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
o `dm' (delete mode) and `xs' are not handled correctly
(they are ignored). `xn' is treated as a magic-margin
indicator.
o Screen has no clue about double-high or double-wide
characters. But this is the only area where vttest is
allowed to fail.
$TERMCAP when reattaching under a different terminal
type.
o The support of terminfo based systems is very limited.
Adding extra capabilities to $TERMCAP may not have any
effects.
o Screen does not make use of hardware tabs.
o 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".
o 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.
o Screen may give a strange warning when your tty has no
utmp entry.
o When the modem line was hung up, screen may not auto-
matically detach (or quit) unless the device driver is
configured to send a HANGUP signal. To detach a screen
session use the -D or -d command line option.
o A weird imagination is most useful to gain full advan-
tage of all the features.
o Send bugreports, fixes, enhancements, t-shirts, money,
beer & pizza to screen@uni-erlangen.de.
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