This is screen.info, produced by makeinfo version 4.2 from
./screen.texinfo.
INFO-DIR-SECTION General Commands
START-INFO-DIR-ENTRY
* Screen: (screen). Full-screen window manager.
END-INFO-DIR-ENTRY
This file documents the `Screen' virtual terminal manager.
Copyright (c) 1993-2003 Free Software Foundation, Inc.
Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.
Permission is granted to copy and distribute modified versions of
this manual under the conditions for verbatim copying, provided that
the entire resulting derived work is distributed under the terms of a
permission notice identical to this one.
Permission is granted to copy and distribute translations of this
manual into another language, under the above conditions for modified
versions, except that this permission notice may be stated in a
translation approved by the Foundation.
File: screen.info, Node: Termcap Examples, Next: Special Capabilities, Prev: Termcap Syntax, Up: Termcap
Termcap Examples
================
Some examples:
termcap xterm* xn:hs@
Informs `screen' that all terminals that begin with `xterm' have firm
auto-margins that allow the last position on the screen to be updated
(xn), but they don't really have a status line (no 'hs' - append `@' to
turn entries off). Note that we assume `xn' for all terminal names
that start with `vt', but only if you don't specify a termcap command
for that terminal.
termcap vt* xn
termcap vt102|vt220 Z0=\E[?3h:Z1=\E[?3l
Specifies the firm-margined `xn' capability for all terminals that
begin with `vt', and the second line will also add the escape-sequences
to switch into (Z0) and back out of (Z1) 132-character-per-line mode if
this is a VT102 or VT220. (You must specify Z0 and Z1 in your termcap
to use the width-changing commands.)
termcap vt100 "" l0=PF1:l1=PF2:l2=PF3:l3=PF4
This leaves your vt100 termcap alone and adds the function key labels to
each window's termcap entry.
termcap h19|z19 am@:im=\E@:ei=\EO dc=\E[P
Takes a h19 or z19 termcap and turns off auto-margins (am@) and enables
the insert mode (im) and end-insert (ei) capabilities (the `@' in the
`im' string is after the `=', so it is part of the string). Having the
`im' and `ei' definitions put into your terminal's termcap will cause
screen to automatically advertise the character-insert capability in
each window's termcap. Each window will also get the delete-character
capability (dc) added to its termcap, which screen will translate into
a line-update for the terminal (we're pretending it doesn't support
character deletion).
If you would like to fully specify each window's termcap entry, you
should instead set the `$SCREENCAP' variable prior to running `screen'.
*Note Virtual Terminal::, for the details of the `screen' terminal
emulation. *Note Termcap: (termcap)Top, for more information on
termcap definitions.
File: screen.info, Node: Special Capabilities, Next: Autonuke, Prev: Termcap Examples, Up: Termcap
Special Terminal Capabilities
=============================
The following table describes all terminal capabilities that are
recognized by `screen' and are not in the termcap manual (*note
Termcap: (termcap)Top.). 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 margins'). Note that this
capability is obsolete -- `screen' now 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 cursor-keys to application mode.
`CE'
(str)
Switch cursor-keys to cursor mode.
`AN'
(bool)
Enable autonuke for displays of this terminal type. (*note
Autonuke::).
`OL'
(num)
Set the output buffer limit. See the `obuflimit' command (*note
Obuflimit::) for more details.
`KJ'
(str)
Set the encoding of the terminal. See the `encoding' command
(*note Character Processing::) for valid encodings.
`AF'
(str)
Change character foreground 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. (*note Character Translation::).
`XT'
(bool)
Terminal understands special xterm sequences (OSC, mouse tracking).
`C8'
(bool)
Terminal needs bold to display high-intensity colors (e.g. Eterm).
`TF'
(bool)
Add missing capabilities to the termcap/info entry. (Set by
default).
File: screen.info, Node: Autonuke, Next: Obuflimit, Prev: Special Capabilities, Up: Termcap
Autonuke
========
- Command: autonuke STATE
(none)
Sets whether a clear screen sequence should nuke all the output
that has not been written to the terminal. *Note Obuflimit::.
This property is set per display, not per window.
- Command: defautonuke STATE
(none)
Same as the `autonuke' command except that the default setting for
new displays is also changed. Initial setting is `off'. Note that
you can use the special `AN' terminal capability if you want to
have a terminal type dependent setting.
File: screen.info, Node: Obuflimit, Next: Character Translation, Prev: Autonuke, Up: Termcap
Obuflimit
=========
- Command: obuflimit [LIMIT]
(none)
If the output buffer contains more bytes than the specified limit,
no more data will be read from the windows. The default value is
256. If you have a fast display (like `xterm'), you can set it to
some higher value. If no argument is specified, the current
setting is displayed. This property is set per display, not per
window.
- Command: defobuflimit LIMIT
(none)
Same as the `obuflimit' command except that the default setting
for new displays is also changed. Initial setting is 256 bytes.
Note that you can use the special `OL' terminal capability if you
want to have a terminal type dependent limit.
File: screen.info, Node: Character Translation, Prev: Obuflimit, Up: Termcap
Character Translation
=====================
`Screen' has a powerful mechanism to translate characters to
arbitrary 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 occurrence 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 quoting 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 normally 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'.
File: screen.info, Node: Message Line, Next: Logging, Prev: Termcap, Up: Top
The Message Line
****************
`screen' displays informational messages and other diagnostics in a
"message line" at the bottom of the screen. If your terminal has a
status line defined in its termcap, screen will use this for displaying
its messages, otherwise the last line of the screen will be temporarily
overwritten and output will be momentarily interrupted. The message
line is automatically removed after a few seconds delay, but it can also
be removed early (on terminals without a status line) by beginning to
type.
* Menu:
* Privacy Message:: Using the message line from your program.
* Hardware Status Line:: Use the terminal's hardware status line.
* Last Message:: Redisplay the last message.
* Message Wait:: Control how long messages are displayed.
File: screen.info, Node: Privacy Message, Next: Hardware Status Line, Up: Message Line
Using the message line from your program
========================================
The message line facility can be used by an application running in
the current window by means of the ANSI "Privacy message" control
sequence. For instance, from within the shell, try something like:
echo "^Hello world from window $WINDOW\"
where `' is ASCII ESC and `^' is a literal caret or up-arrow.
File: screen.info, Node: Hardware Status Line, Next: Last Message, Prev: Privacy Message, Up: Message Line
Hardware Status Line
====================
- Command: hardstatus [state]
- Command: hardstatus [`always']`lastline'|`message'|`ignore' [string]
- Command: hardstatus `string' [string]
(none)
This command configures the use and emulation of the terminal's
hardstatus line. The first form toggles whether `screen' will use
the hardware status line to display messages. If the flag is set
to `off', these messages are overlaid in reverse video mode at the
display line. The default setting is `on'.
The second form tells screen what to do if the terminal doesn't
have a hardstatus line (i.e. the termcap/terminfo capabilities
"hs", "ts", "fs" and "ds" are not set). If the type `lastline' is
used, screen will reserve the last line of the display for the
hardstatus. `message' uses `screen''s message mechanism and
`ignore' tells `screen' never to display the hardstatus. If you
prepend the word `always' to the type (e.g., `alwayslastline'),
`screen' will use the type even if the terminal supports a
hardstatus line.
The third form specifies the contents of the hardstatus line.
`%h' is used as default string, i.e. the stored hardstatus of the
current window (settable via `ESC]0;^G' or `ESC_\\') is displayed.
You can customize this to any string you like including string
escapes (*note String Escapes::). If you leave out the argument
STRING, the current string is displayed.
You can mix the second and third form by providing the string as
additional argument.
File: screen.info, Node: Last Message, Next: Message Wait, Prev: Hardware Status Line, Up: Message Line
Display Last Message
====================
- Command: lastmsg
(`C-a m', `C-a C-m')
Repeat the last message displayed in the message line. Useful if
you're typing when a message appears, because (unless your
terminal has a hardware status line) the message goes away when
you press a key.
File: screen.info, Node: Message Wait, Prev: Last Message, Up: Message Line
Message Wait
============
- Command: msgminwait sec
(none)
Defines the time `screen' delays a new message when another is
currently displayed. Defaults to 1 second.
- Command: msgwait sec
(none)
Defines the time a message is displayed, if `screen' is not
disturbed by other activity. Defaults to 5 seconds.
File: screen.info, Node: Logging, Next: Startup, Prev: Message Line, Up: Top
Logging
*******
This section describes the commands for keeping a record of your
session.
* Menu:
* Hardcopy:: Dump the current screen to a file
* Log:: Log the output of a window to a file
File: screen.info, Node: Hardcopy, Next: Log, Up: Logging
hardcopy
========
- Command: hardcopy [-h] [FILE]
(`C-a h', `C-a C-h')
Writes out the currently displayed image to the file FILE, or, if
no filename is specified, to `hardcopy.N' in the default
directory, where N is the number of the current window. This
either appends or overwrites the file if it exists, as determined
by the `hardcopy_append' command. If the option `-h' is
specified, dump also the contents of the scrollback buffer.
- Command: hardcopy_append state
(none)
If set to `on', `screen' will append to the `hardcopy.N' files
created by the command `hardcopy'; otherwise, these files are
overwritten each time.
- Command: hardcopydir directory
(none)
Defines a directory where hardcopy files will be placed. If unset
hardcopys are dumped in screen's current working directory.
File: screen.info, Node: Log, Prev: Hardcopy, Up: Logging
log
===
- Command: deflog state
(none)
Same as the `log' command except that the default setting for new
windows is changed. Initial setting is `off'.
- Command: log [state]
(`C-a H')
Begins/ends logging of the current window to the file
`screenlog.N' in the window's default directory, where N is the
number of the current window. This filename can be changed with
the `logfile' command. If no parameter is given, the logging
state is toggled. The session log is appended to the previous
contents of the file if it already exists. The current contents
and the contents of the scrollback history are not included in the
session log. Default is `off'.
- Command: logfile filename
- Command: logfile flush secs
(none)
Defines the name the logfiles will get. The default is
`screenlog.%n'. The second form changes the number of seconds
`screen' will wait before flushing the logfile buffer to the
file-system. The default value is 10 seconds.
- Command: logtstamp [state]
- Command: logtstamp `after' secs
- Command: logtstamp `string' string
(none)
This command controls logfile time-stamp mechanism of screen. If
time-stamps are turned `on', screen adds a string containing the
current time to the logfile after two minutes of inactivity. When
output continues and more than another two minutes have passed, a
second time-stamp is added to document the restart of the output.
You can change this timeout with the second form of the command.
The third form is used for customizing the time-stamp string (`--
%n:%t -- time-stamp -- %M/%d/%y %c:%s --\n' by default).
File: screen.info, Node: Startup, Next: Miscellaneous, Prev: Logging, Up: Top
Startup
*******
This section describes commands which are only useful in the
`.screenrc' file, for use at startup.
* Menu:
* echo:: Display a message.
* sleep:: Pause execution of the `.screenrc'.
* Startup Message:: Control display of the copyright notice.
File: screen.info, Node: echo, Next: sleep, Up: Startup
echo
====
- Command: echo [`-n'] message
(none)
The echo command may be used to annoy `screen' users with a
'message of the day'. Typically installed in a global screenrc.
The option `-n' may be used to suppress the line feed. See also
`sleep'. Echo is also useful for online checking of environment
variables.
File: screen.info, Node: sleep, Next: Startup Message, Prev: echo, Up: Startup
sleep
=====
- Command: sleep num
(none)
This command will pause the execution of a .screenrc file for NUM
seconds. Keyboard activity will end the sleep. It may be used to
give users a chance to read the messages output by `echo'.
File: screen.info, Node: Startup Message, Prev: sleep, Up: Startup
Startup Message
===============
- Command: startup_message state
(none)
Select whether you want to see the copyright notice during startup.
Default is `on', as you probably noticed.
File: screen.info, Node: Miscellaneous, Next: String Escapes, Prev: Startup, Up: Top
Miscellaneous commands
**********************
The commands described here do not fit well under any of the other
categories.
* Menu:
* At:: Execute a command at other displays or windows.
* Break:: Send a break signal to the window.
* Debug:: Suppress/allow debugging output.
* License:: Display the disclaimer page.
* Nethack:: Use `nethack'-like error messages.
* Nonblock:: Disable flow-control to a display.
* Number:: Change the current window's number.
* Silence:: Notify on inactivity.
* Time:: Display the time and load average.
* Verbose:: Display window creation commands.
* Version:: Display the version of `screen'.
* Zombie:: Keep dead windows.
* Printcmd:: Set command for VT100 printer port emulation.
* Sorendition:: Change the text highlighting method.
* Attrcolor:: Map attributes to colors.
* Setsid:: Change process group management
* Eval:: Parse and execute arguments
* Maxwin:: Set the maximum window number
* Backtick:: Program a command for a backtick string escape.
File: screen.info, Node: At, Next: Break, Up: Miscellaneous
At
==
- Command: at [identifier][#|*|%] command [args]
(none)
Execute a command at other displays or windows as if it had been
entered there. `At' changes the context (the `current window' or
`current display' setting) of the command. If the first parameter
describes a non-unique context, the command will be executed
multiple times. If the first parameter is of the form
`IDENTIFIER*' then identifier is matched against user names. The
command is executed once for each display of the selected user(s).
If the first parameter is of the form `IDENTIFIER%' identifier is
matched against displays. Displays are named after the ttys they
attach. The prefix `/dev/' or `/dev/tty' may be 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 windows because a prefix-match is performed. Note that
on the affected display(s) a short message will describe what
happened. Note that the `#' character works as a comment
introducer when it is preceded by whitespace. This can be escaped
by prefixing `#' with a `\'. Permission is checked for the
initiator of the `at' command, not for the owners of the affected
display(s). Caveat: When matching against windows, the command is
executed at least once per window. Commands that change the
internal arrangement of windows (like `other') may be called
again. In shared windows the command will be repeated for each
attached display. Beware, when issuing toggle commands like
`login'! Some commands (e.g. `\*Qprocess') require that a display
is associated with the target windows. These commands may not
work correctly under `at' looping over windows.
File: screen.info, Node: Break, Next: Debug, Prev: At, Up: Miscellaneous
Break
=====
- Command: break [duration]
(none)
Send a break signal for DURATION*0.25 seconds to this window. For
non-Posix systems the time interval is rounded up to full seconds.
Most useful if a character device is attached to the window rather
than a shell process (*note Window Types::). The maximum duration
of a break signal is limited to 15 seconds.
- Command: pow_break
(none)
Reopen the window's terminal line and send a break condition.
- Command: breaktype [tcsendbreak|TIOCSBRK|TCSBRK]
(none)
Choose one of the available methods of generating a break signal
for terminal devices. This command should affect the current
window only. But it still behaves identical to `defbreaktype'.
This will be changed in the future. Calling `breaktype' with no
parameter displays the break setting for the current window.
- Command: defbreaktype [tcsendbreak|TIOCSBRK|TCSBRK]
(none)
Choose one of the available methods of generating a break signal
for terminal devices opened afterwards. The preferred methods are
`tcsendbreak' and `TIOCSBRK'. The third, `TCSBRK', blocks the
complete `screen' session for the duration of the break, but it
may be the only way to generate long breaks. `tcsendbreak' and
`TIOCSBRK' may or may not produce long breaks with spikes (e.g. 4
per second). This is not only system dependant, this also differs
between serial board drivers. Calling `defbreaktype' with no
parameter displays the current setting.
File: screen.info, Node: Debug, Next: License, Prev: Break, Up: Miscellaneous
Debug
=====
- Command: debug [on|off]
(none)
Turns runtime debugging on or off. If `screen' has been compiled
with option `-DDEBUG' debugging is available and is turned on per
default. Note that this command only affects debugging output
from the main `SCREEN' process correctly. Debug output from
attacher processes can only be turned off once and forever.
File: screen.info, Node: License, Next: Nethack, Prev: Debug, Up: Miscellaneous
License
=======
- Command: license
(none)
Display the disclaimer page. This is done whenever `screen' is
started without options, which should be often enough.
File: screen.info, Node: Nethack, Next: Nonblock, Prev: License, Up: Miscellaneous
Nethack
=======
- Command: nethack state
(none)
Changes the kind of error messages used by `screen'. When you are
familiar with the game `nethack', you may enjoy the nethack-style
messages which will often blur the facts a little, but are much
funnier to read. Anyway, standard messages often tend to be
unclear as well.
This option is only available if `screen' was compiled with the
NETHACK flag defined (*note Installation::). The default setting
is then determined by the presence of the environment variable
`$NETHACKOPTIONS'.
File: screen.info, Node: Nonblock, Next: Number, Prev: Nethack, Up: Miscellaneous
Nonblock
========
- Command: nonblock STATE
Enable or disable flow control for the current user interface
(display). It is used to prevent a slow display from slowing down
the processing of data output by a window. This command may be
helpful when multiple displays show the same window. `Nonblock'
is initially off for all displays.
File: screen.info, Node: Number, Next: Silence, Prev: Nonblock, Up: Miscellaneous
Number
======
- Command: number [N]
(`C-a N')
Change the current window's 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.
File: screen.info, Node: Silence, Next: Time, Prev: Number, Up: Miscellaneous
Silence
=======
- Command: silence [STATE|SEC]
(none)
Toggles silence monitoring of windows. When silence is turned on
and an affected window is switched into the background, you will
receive the silence notification message in the status line after
a specified period of inactivity (silence). The default timeout
can be changed with the `silencewait' command or by specifying a
number of seconds instead of `on' or `off'. Silence is initially
off for all windows.
- Command: defsilence state
(none)
Same as the `silence' command except that the default setting for
new windows is changed. Initial setting is `off'.
- Command: silencewait SECONDS
(none)
Define the time that all windows monitored for silence should wait
before displaying a message. Default is 30 seconds.
File: screen.info, Node: Time, Next: Verbose, Prev: Silence, Up: Miscellaneous
Time
====
- Command: time [STRING]
(`C-a t', `C-a C-t')
Uses the message line to display the time of day, the host name,
and the load averages over 1, 5, and 15 minutes (if this is
available on your system). For window-specific information use
`info' (*note Info::). If a STRING is specified, it changes the
format of the time report like it is described in the string
escapes chapter (*note String Escapes::). Screen uses a default of
`%c:%s %M %d %H%? %l%?'.
File: screen.info, Node: Verbose, Next: Version, Prev: Time, Up: Miscellaneous
Verbose
=======
- Command: verbose [on|off]
If verbose is switched on, the command name is echoed, whenever a
window is created (or resurrected from zombie state). Default is
off. Without parameter, the current setting is shown.
File: screen.info, Node: Version, Next: Zombie, Prev: Verbose, Up: Miscellaneous
Version
=======
- Command: version
(`C-a v')
Display the version and modification date in the message line.
File: screen.info, Node: Zombie, Next: Printcmd, Prev: Version, Up: Miscellaneous
Zombie
======
- Command: zombie [KEYS]
- Command: defzombie [KEYS]
(none)
Per default 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' command may be used to remove the window.
Pressing the first key in the dead window has the same effect.
Pressing the second key, however, 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 the
process terminates.
As the zombie setting is affected globally for all windows, this
command should only be called `defzombie'. Until we need this as a
per window setting, the commands `zombie' and `defzombie' are
synonymous.
File: screen.info, Node: Printcmd, Next: Sorendition, Prev: Zombie, Up: Miscellaneous
Printcmd
========
- Command: printcmd [CMD]
(none)
If CMD is not an empty string, screen will not use the terminal
capabilities `po/pf' for printing 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 an argument 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.
File: screen.info, Node: Sorendition, Next: Attrcolor, Prev: Printcmd, Up: Miscellaneous
Sorendition
===========
- Command: sorendition [ATTR [COLOR]]
(none)
Change the way screen does highlighting for text marking and
printing messages. See the chapter about string escapes (*note
String Escapes::) for the syntax of the modifiers. The default is
currently `=s dd' (standout, default colors).
File: screen.info, Node: Attrcolor, Next: Setsid, Prev: Sorendition, Up: Miscellaneous
Attrcolor
=========
- Command: attrcolor ATTRIB [ATTRIBUTE/COLOR-MODIFIER]
(none)
This command can be used to highlight attributes by changing the
color of the text. If the attribute ATTRIB is in use, the
specified attribute/color modifier is also applied. If no modifier
is given, the current one is deleted. See the chapter about string
escapes (*note String Escapes::) for the syntax of the modifier.
Screen understands two pseudo-attributes, `i' stands for
high-intensity foreground color and `I' for high-intensity
background color.
Examples:
`attrcolor b "R"'
Change the color to bright red if bold text is to be printed.
`attrcolor u "-u b"'
Use blue text instead of underline.
`attrcolor b ".I"'
Use bright colors for bold text. Most terminal emulators do
this already.
`attrcolor i "+b"'
Make bright colored text also bold.
File: screen.info, Node: Setsid, Next: Eval, Prev: Attrcolor, Up: Miscellaneous
Setsid
======
- Command: setsid state
(none)
Normally screen uses different sessions and process groups for the
windows. If setsid is turned `off', this is not done anymore and
all windows will be in the same process group as the screen
backend process. This also breaks job-control, so be careful. The
default is `on', of course. This command is probably useful only
in rare circumstances.
File: screen.info, Node: Eval, Next: Maxwin, Prev: Setsid, Up: Miscellaneous
Eval
====
- Command: eval COMMAND1 [COMMAND2 ...]
(none)
Parses and executes each argument as separate command.
File: screen.info, Node: Maxwin, Next: Backtick, Prev: Eval, Up: Miscellaneous
Maxwin
======
- Command: maxwin N
(none)
Set the maximum window number screen will create. Doesn't affect
already existing windows. The number may only be decreased.
File: screen.info, Node: Backtick, Prev: Maxwin, Up: Miscellaneous
Backtick
========
- Command: backtick ID LIFESPAN AUTOREFRESH COMMAND [ARGS]
- Command: backtick ID
(none)
Program the backtick command with the numerical id ID. The output
of such a command is used for substitution of the `%`' string
escape (*note String Escapes::). The specified LIFESPAN is the
number of seconds the output is considered valid. After this time,
the command is run again if a corresponding string escape is
encountered. The AUTOREFRESH parameter triggers an automatic
refresh for caption and hardstatus strings after the specified
number of seconds. Only the last line of output is used for
substitution.
If both the LIFESPAN and the AUTOREFRESH parameters are zero, the
backtick program is expected to stay in the background and
generate output once in a while. In this case, the command is
executed right away and screen stores the last line of output. If
a new line gets printed screen will automatically refresh the
hardstatus or the captions.
The second form of the command deletes the backtick command with
the numerical id ID.
File: screen.info, Node: String Escapes, Next: Environment, Prev: Miscellaneous, Up: Top
String Escapes
**************
Screen provides an escape mechanism to insert information like the
current time into messages or file names. The escape character is `%'
with one exception: inside of a window's hardstatus `^%' (`^E') is used
instead.
Here is the full list of supported escapes:
`%'
the escape character itself
`a'
either `am' or `pm'
`A'
either `AM' or `PM'
`c'
current time `HH:MM' in 24h format
`C'
current time `HH:MM' in 12h format
`d'
day number
`D'
weekday name
`f'
flags of the window
`F'
sets %? to true if the window has the focus
`h'
hardstatus of the window
`H'
hostname of the system
`l'
current load of the system
`m'
month number
`M'
month name
`n'
window number
`s'
seconds
`t'
window title
`u'
all other users on this window
`w'
all window numbers and names. With `-' quailifier: up to the
current window; with `+' qualifier: starting with the window after
the current one.
`W'
all window numbers and names except the current one
`y'
last two digits of the year number
`Y'
full year number
`?'
the part to the next `%?' is displayed only if a `%' escape inside
the part expands to a non-empty string
`:'
else part of `%?'
`='
pad the string to the display's width (like TeX's hfill). If a
number is specified, pad to the percentage of the window's width.
A `0' qualifier tells screen to treat the number as absolute
position. You can specify to pad relative to the last absolute
pad position by adding a `+' qualifier or to pad relative to the
right margin by using `-'. The padding truncates the string if the
specified position lies before the current position. Add the `L'
qualifier to change this.
`<'
same as `%=' but just do truncation, do not fill with spaces
`>'
mark the current text position for the next truncation. When
screen needs to do truncation, it tries to do it in a way that the
marked position gets moved to the specified percentage of the
output area. (The area starts from the last absolute pad position
and ends with the position specified by the truncation operator.)
The `L' qualifier tells screen to mark the truncated parts with
`...'.
`{'
attribute/color modifier string terminated by the next `}'
``'
Substitute with the output of a `backtick' command. The length
qualifier is misused to identify one of the commands. *Note
Backtick::. The `c' and `C' escape may be qualified with a `0' to
make screen use zero instead of space as fill character. The `n' and
`=' escapes understand a length qualifier (e.g. `%3n'), `D' and `M' can
be prefixed with `L' to generate long names, `w' and `W' also show the
window flags if `L' is given.
An attribute/color modifier is is used to change the attributes or
the color settings. Its format is `[attribute modifier] [color
description]'. The attribute modifier must be prefixed by a change type
indicator if it can be confused with a color desciption. The following
change types are known:
`+'
add the specified set to the current attributes
`-'
remove the set from the current attributes
`!'
invert the set in the current attributes
`='
change the current attributes to the specified set The attribute
set can either be specified as a hexadecimal number or a combination of
the following letters:
`d'
dim
`u'
underline
`b'
bold
`r'
reverse
`s'
standout
`B'
blinking Colors are coded either as a hexadecimal number or two
letters specifying the desired background and foreground color (in that
order). The following colors are known:
`k'
black
`r'
red
`g'
green
`y'
yellow
`b'
blue
`m'
magenta
`c'
cyan
`w'
white
`d'
default color
`.'
leave color unchanged The capitalized versions of the letter
specify bright colors. You can also use the pseudo-color `i' to set
just the brightness and leave the color unchanged.
A one digit/letter color description is treated as foreground or
background color dependant on the current attributes: if reverse mode is
set, the background color is changed instead of the foreground color.
If you don't like this, prefix the color with a `.'. If you want the
same behaviour for two-letter color descriptions, also prefix them with
a `.'.
As a special case, `%{-}' restores the attributes and colors that
were set before the last change was made (i.e. pops one level of the
color-change stack).
Examples:
`G'
set color to bright green
`+b r'
use bold red
`= yd'
clear all attributes, write in default color on yellow background.
`%-Lw%{= BW}%50>%n%f* %t%{-}%+Lw%<'
The available windows centered at the current win dow and
truncated to the available width. The current window is displayed
white on blue. This can be used with `hardstatus alwayslastline'.
`%?%F%{.R.}%?%3n %t%? [%h]%?'
The window number and title and the window's hardstatus, if one is
set. Also use a red background if this is the active focus.
Useful for `caption string'.
File: screen.info, Node: Environment, Next: Files, Prev: String Escapes, Up: Top
Environment Variables
*********************
`COLUMNS'
Number of columns on the terminal (overrides termcap entry).
`HOME'
Directory in which to look for .screenrc.
`LINES'
Number of lines on the terminal (overrides termcap entry).
`LOCKPRG'
Screen lock program.
`NETHACKOPTIONS'
Turns on `nethack' option.
`PATH'
Used for locating programs to run.
`SCREENCAP'
For customizing a terminal's `TERMCAP' value.
`SCREENDIR'
Alternate socket directory.
`SCREENRC'
Alternate user screenrc file.
`SHELL'
Default shell program for opening windows (default `/bin/sh').
`STY'
Alternate socket name. If `screen' is invoked, and the environment
variable `STY' is set, then it creates only a window in the
running `screen' session rather than starting a new session.
`SYSSCREENRC'
Alternate system screenrc file.
`TERM'
Terminal name.
`TERMCAP'
Terminal description.
`WINDOW'
Window number of a window (at creation time).
File: screen.info, Node: Files, Next: Credits, Prev: Environment, Up: Top
Files Referenced
****************
`.../screen-3.?.??/etc/screenrc'
`.../screen-3.?.??/etc/etcscreenrc'
Examples in the `screen' distribution package for private and
global initialization files.
``$SYSSCREENRC''
`/local/etc/screenrc'
`screen' initialization commands
``$SCREENRC''
``$HOME'/.iscreenrc'
``$HOME'/.screenrc'
Read in after /local/etc/screenrc
``$SCREENDIR'/S-LOGIN'
`/local/screens/S-LOGIN'
Socket directories (default)
`/usr/tmp/screens/S-LOGIN'
Alternate socket directories.
`SOCKET DIRECTORY/.termcap'
Written by the `dumptermcap' command
`/usr/tmp/screens/screen-exchange or'
`/tmp/screen-exchange'
`screen' interprocess communication buffer
`hardcopy.[0-9]'
Screen images created by the hardcopy command
`screenlog.[0-9]'
Output log files created by the log command
`/usr/lib/terminfo/?/* or'
`/etc/termcap'
Terminal capability databases
`/etc/utmp'
Login records
``$LOCKPRG''
Program for locking the terminal.
File: screen.info, Node: Credits, Next: Bugs, Prev: Files, Up: Top
Credits
*******
Authors
=======
Originally created by Oliver Laumann, this latest version was
produced by Wayne Davison, Juergen Weigert and Michael Schroeder.
Contributors
============
Ken Beal (kbeal@amber.ssd.csd.harris.com),
Rudolf Koenig (rfkoenig@informatik.uni-erlangen.de),
Toerless Eckert (eckert@informatik.uni-erlangen.de),
Wayne Davison (davison@borland.com),
Patrick Wolfe (pat@kai.com, kailand!pat),
Bart Schaefer (schaefer@cse.ogi.edu),
Nathan Glasser (nathan@brokaw.lcs.mit.edu),
Larry W. Virden (lvirden@cas.org),
Howard Chu (hyc@hanauma.jpl.nasa.gov),
Tim MacKenzie (tym@dibbler.cs.monash.edu.au),
Markku Jarvinen (mta@{cc,cs,ee}.tut.fi),
Marc Boucher (marc@CAM.ORG),
Doug Siebert (dsiebert@isca.uiowa.edu),
Ken Stillson (stillson@tsfsrv.mitre.org),
Ian Frechett (frechett@spot.Colorado.EDU),
Brian Koehmstedt (bpk@gnu.ai.mit.edu),
Don Smith (djs6015@ultb.isc.rit.edu),
Frank van der Linden (vdlinden@fwi.uva.nl),
Martin Schweikert (schweik@cpp.ob.open.de),
David Vrona (dave@sashimi.lcu.com),
E. Tye McQueen (tye%spillman.UUCP@uunet.uu.net),
Matthew Green (mrg@eterna.com.au),
Christopher Williams (cgw@pobox.com),
Matt Mosley (mattm@access.digex.net),
Gregory Neil Shapiro (gshapiro@wpi.WPI.EDU),
Jason Merrill (jason@jarthur.Claremont.EDU),
Johannes Zellner (johannes@zellner.org),
Pablo Averbuj (pablo@averbuj.com).
Version
=======
This manual describes version 3.9.15 of the `screen' program. 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.
See also *Note Availability::.
File: screen.info, Node: Bugs, Next: Installation, Prev: Credits, Up: Top
Bugs
****
Just like any other significant piece of software, `screen' has a
few bugs and missing features. Please send in a bug report if you have
found a bug not mentioned here.
* Menu:
* Known Bugs:: Problems we know about.
* Reporting Bugs:: How to contact the maintainers.
* Availability:: Where to find the lastest screen version.
File: screen.info, Node: Known Bugs, Next: Reporting Bugs, Up: Bugs
Known 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 setuid root on most systems in order to
be able to correctly change the owner of the tty device file for
each window. Special permission may also be required to write the
file `/etc/utmp'.
* Entries in `/etc/utmp' are not removed when `screen' is killed
with SIGKILL. This will cause some programs (like "w" or "rwho")
to advertise that a user is logged on who really isn't.
* `screen' may give a strange warning when your tty has no utmp
entry.
* When the modem line was hung up, `screen' may not automatically
detach (or quit) unless the device driver sends a HANGUP signal.
To detach such a `screen' session use the -D or -d command line
option.
* If a password is set, the command line options -d and -D still
detach a session without asking.
* Both `breaktype' and `defbreaktype' change the break generating
method used by all terminal devices. The first should change a
window specific setting, where the latter should change only the
default for new windows.
* When attaching to a multiuser session, the user's `.screenrc' file
is not sourced. Each users personal settings have to be included
in the `.screenrc' file from which the session is booted, or have
to be changed manually.
* A weird imagination is most useful to gain full advantage of all
the features.
File: screen.info, Node: Reporting Bugs, Next: Availability, Prev: Known Bugs, Up: Bugs
Reporting Bugs
==============
If you find a bug in `Screen', please send electronic mail to
`screen@uni-erlangen.de', and also to `bug-gnu-utils@prep.ai.mit.edu'.
Include the version number of `Screen' which you are using. Also
include in your message the hardware and operating system, the compiler
used to compile, a description of the bug behavior, and the conditions
that triggered the bug. Please recompile `screen' with the `-DDEBUG'
options enabled, reproduce the bug, and have a look at the debug output
written to the directory `/tmp/debug'. If necessary quote suspect
passages from the debug output and show the contents of your `config.h'
if it matters.
File: screen.info, Node: Availability, Prev: Reporting Bugs, Up: Bugs
Availability
============
`Screen' is available under the `GNU' copyleft.
The latest official release of `screen' available via anonymous ftp
from `prep.ai.mit.edu', `nic.funet.fi' or any other `GNU' distribution
site. The home site of `screen' is `ftp.uni-erlangen.de
(131.188.3.71)', in the directory `pub/utilities/screen'. The
subdirectory `private' contains the latest beta testing release. If
you want to help, send a note to screen@uni-erlangen.de.
File: screen.info, Node: Installation, Next: Concept Index, Prev: Bugs, Up: Top
Installation
************
Since `screen' uses pseudo-ttys, the select system call, and
UNIX-domain sockets/named pipes, it will not run under a system that
does not include these features of 4.2 and 4.3 BSD UNIX.
* Menu:
* Socket Directory:: Where screen stores its handle.
* Compiling Screen::
File: screen.info, Node: Socket Directory, Next: Compiling Screen, Up: Installation
Socket Directory
================
The socket directory defaults either to `$HOME/.screen' or simply to
`/tmp/screens' or preferably to `/usr/local/screens' chosen at
compile-time. If `screen' is installed setuid root, then the
administrator should compile screen with an adequate (not NFS mounted)
`SOCKDIR'. If `screen' is not running setuid-root, the user can specify
any mode 700 directory in the environment variable `$SCREENDIR'.
File: screen.info, Node: Compiling Screen, Prev: Socket Directory, Up: Installation
Compiling Screen
================
To compile and install screen:
The `screen' package comes with a `GNU Autoconf' configuration
script. Before you compile the package run
`sh ./configure'
This will create a `config.h' and `Makefile' for your
machine. If `configure' fails for some reason, then look at the
examples and comments found in the `Makefile.in' and `config.h.in'
templates. Rename `config.status' to `config.status.MACHINE' when you
want to keep configuration data for multiple architectures. Running `sh
./config.status.MACHINE' recreates your configuration significantly
faster than rerunning `configure'.
Read through the "User Configuration" section of `config.h', and verify
that it suits your needs. A comment near the top of this section
explains why it's best to install screen setuid to root. Check for the
place for the global `screenrc'-file and for the socket directory.
Check the compiler used in `Makefile', the prefix path where to install
`screen'. Then run
`make'
If `make' fails to produce one of the files `term.h', `comm.h'
or `tty.c', then use `FILENAME.X.dist' instead. For additional
information about installation of `screen' refer to the file
`INSTALLATION', coming with this package.
File: screen.info, Node: Concept Index, Next: Command Index, Prev: Installation, Up: Top
Concept Index
*************
* Menu:
* .screenrc: Startup Files.
* availability: Availability.
* binding: Key Binding.
* bug report: Reporting Bugs.
* bugs: Bugs.
* capabilities: Special Capabilities.
* command character: Command Character.
* command line options: Invoking Screen.
* command summary: Command Summary.
* compiling screen: Compiling Screen.
* control sequences: Control Sequences.
* copy and paste: Copy and Paste.
* customization: Customization.
* environment: Environment.
* escape character: Command Character.
* files: Files.
* flow control: Flow Control.
* input translation: Input Translation.
* installation: Installation.
* introduction: Getting Started.
* invoking: Invoking Screen.
* key binding: Key Binding.
* marking: Copy.
* message line: Message Line.
* multiuser session: Multiuser Session.
* options: Invoking Screen.
* overview: Overview.
* regions: Regions.
* screenrc: Startup Files.
* scrollback: Copy.
* socket directory: Socket Directory.
* string escapes: String Escapes.
* terminal capabilities: Special Capabilities.
* title: Naming Windows.
* window types: Window Types.