table of contents
- NAME
- SYNOPSIS
- DESCRIPTION
- GETTING STARTED
- COMMAND-LINE OPTIONS
- DEFAULT KEY BINDINGS
- CUSTOMIZATION
- THE MESSAGE LINE
- WINDOW TYPES
- STRING ESCAPES
- FLOW-CONTROL
- TITLES (naming windows)
- THE VIRTUAL TERMINAL
- INPUT TRANSLATION
- SPECIAL TERMINAL CAPABILITIES
- CHARACTER TRANSLATION
- ENVIRONMENT
- FILES
- SEE ALSO
- AUTHORS
- COPYLEFT
- CONTRIBUTORS
- VERSION
- AVAILABILITY
- BUGS
other sections
SCREEN(1) | General Commands Manual | SCREEN(1) |
NAME¶
screen - screen manager with VT100/ANSI terminal emulationSYNOPSIS¶
screen [ -options ] [ cmd [ args ] ]DESCRIPTION¶
Screen is a full-screen window manager that multiplexes a physical terminal between several processes (typically interactive shells). Each virtual terminal provides the functions of a DEC VT100 terminal and, in addition, several control functions from the ISO 6429 (ECMA 48, ANSI X3.64) and ISO 2022 standards (e.g. insert/delete line and support for multiple character sets). There is a scrollback history buffer for each virtual terminal and a copy-and-paste mechanism that allows moving text regions between windows. When screen is called, it creates a single window with a shell in it (or the specified command) and then gets out of your way so that you can use the program as you normally would. Then, at any time, you can create new (full-screen) windows with other programs in them (including more shells), kill existing windows, view a list of windows, turn output logging on and off, copy-and-paste text between windows, view the scrollback history, switch between windows in whatever manner you wish, etc. All windows run their programs completely independent of each other. Programs continue to run when their window is currently not visible and even when the whole screen session is detached from the user's terminal. 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. Shells usually distinguish between running as login-shell or sub-shell. Screen runs them as sub-shells, unless told otherwise (See "shell" .screenrc command). 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. Screen does not understand the prefix "C-" to mean control, although this notation is used in this manual for readability. Please use the caret notation ("^A" instead of "C-a") as arguments to e.g. the escape command or the -e option. Screen will also print out control characters in caret notation. The standard way to create a new window is to type "C-a c". This creates a new window running a shell and switches to that window immediately, regardless of the state of the process running in the current window. Similarly, you can create a new window with a custom command in it by first binding the command to a keystroke (in your .screenrc file or at the "C-a :" command line) and then using it just like the "C-a c" command. In addition, new windows can be created by running a command like:- screen emacs prog.c
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 BINDINGS". 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 using a version of your terminal's termcap that has automatic margins turned off. This will ensure an accurate and optimal update of the screen in all circumstances. Most terminals nowadays have "magic" margins (automatic margins plus usable last column). This is the VT100 style type and perfectly suited for screen. If all you've got is a "true" auto-margin terminal screen will be content to use it, but updating a character put into the last position on the screen may not be possible until the screen scrolls or the character is moved into a safe position in some other way. This delay can be shortened by using a terminal with insert-character capability.COMMAND-LINE OPTIONS¶
Screen has the following command-line options:- -a
- include all capabilities (with some minor exceptions) in each window's termcap, even if screen must redraw parts of the display in order to implement a function.
- -A
- Adapt the sizes of all windows to the size of the current terminal. By default, screen tries to restore its old window sizes when attaching to resizable terminals (those with "WS" in its description, e.g. suncmd or some xterm).
- -c file
- override the default configuration file from "$HOME/.screenrc" to file.
- -d|-D [pid.tty.host]
- does not start screen, but detaches the elsewhere running screen 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. In combination with the -r/-R option more powerful effects can be achieved:
- -d -r
- Reattach a session and if necessary detach it first.
- -d -R
- Reattach a session and if necessary detach or even create it first.
- -d -RR
- Reattach a session and if necessary detach or create it. Use the first session if more than one session is available.
- -D -r
- Reattach a session. If necessary detach and logout remotely first.
- -D -R
- Attach here and now. In detail this means: If a session is running, then reattach. If necessary detach and logout remotely first. If it was not running create it and notify the user. This is the author's favorite.
- -D -RR
- Attach here and now. Whatever that means, just do it.
- Note: It is always a good idea to check the status of your sessions by means of "screen -list".
- -e xy
- specifies the command character to be x and the character 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 command character. But when attaching to an already running 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 "defflow" .screenrc command.
- -h num
- Specifies the history scrollback buffer to be num lines high.
- -i
- will cause the interrupt key (usually C-c) to interrupt the display immediately when flow-control is on. See the "defflow" .screenrc command for details. The use of this option is discouraged.
- -l and -ln
- turns login mode on or off (for /var/run/utmp updating). This can also be defined through the "deflogin" .screenrc command.
- -ls [match]
- -list [match]
- does not start screen, but prints a list of pid.tty.host strings and creation timestamps identifying your screen sessions. Sessions marked `detached' can be resumed with "screen -r". Those marked `attached' are running and have a controlling terminal. If the session runs in multiuser mode, it is marked `multi'. Sessions marked as `unreachable' either live on a different host or are `dead'. An unreachable session is considered dead, when its name matches either the name of the local host, or the specified parameter, if any. See the -r flag for a description how to construct matches. 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 to turn on automatic output logging for the windows.
- -m
- causes screen to ignore the $STY environment variable. With "screen -m" creation of a new session is enforced, regardless whether screen is called from within another screen session or not. This flag has a special meaning in connection with the `-d' option:
- -d -m
- Start screen in "detached" mode. This creates a new session but doesn't attach to it. This is useful for system startup scripts.
- -D -m
- This also starts screen in "detached" mode, but doesn't fork a new process. The command exits if the session terminates.
- -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.
- -p number_or_name|-|=|+
- Preselect a window. This is useful when you want to reattach to a specific window or you want to send a command via the "-X" option to a specific window. As with screen's select command, "-" selects the blank window. As a special case for reattach, "=" brings up the windowlist on the blank window, while a "+" will create a new window. The command will not be executed if the specified window could not be found.
- -q
- Suppress printing of error messages. In combination with "-ls" the exit value is as follows: 9 indicates a directory without sessions. 10 indicates a directory with running but not attachable sessions. 11 (or more) indicates 1 (or more) usable sessions. In combination with "-r" the exit value is as follows: 10 indicates that there is no session to resume. 12 (or more) indicates that there are 2 (or more) sessions to resume and you should specify which one to choose. In all other cases "-q" has no effect.
- -Q
- Some commands now can be queried from a remote session using this flag,
e.g. "screen -Q windows". The commands will send the response to
the stdout of the querying process. If there was an error in the command,
then the querying process will exit with a non-zero status.
The commands that can be queried now are:
echo
info
lastmsg
number
select
time
title
windows
- -r [pid.tty.host]
- -r sessionowner/[pid.tty.host]
- resumes a detached screen session. No other options (except combinations with -d/-D) may be specified, though an optional prefix of [ pid.]tty.host may be needed to distinguish between multiple detached screen sessions. The second form is used to connect to another user's screen session which runs in multiuser mode. This indicates that screen should look for sessions in another user's directory. This requires setuid-root.
- -R
- attempts to resume the youngest (in terms of creation time) 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 (actually screen uses "-xRR" in that case). For combinations with the -d/-D option see there. Note: Time-based session selection is a Debian addition.
- -s program
- 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. See also there.
- -S sessionname
- When creating a new session, this option can be used to specify a meaningful name for the session. This name identifies the session for "screen -list" and "screen -r" actions. It substitutes the default [ tty.host] suffix.
- -t name
- sets the title (a.k.a.) for the default shell or specified program. See also the "shelltitle" .screenrc command.
- -T term
- Set the $TERM environment varible using the spcified term as opposed to the defualt setting of screen.
- -U
- Run screen in UTF-8 mode. This option tells screen that your terminal sends and understands UTF-8 encoded characters. It also sets the default encoding for new windows to `utf8'.
- -v
- Print version number.
- -wipe [match]
- does the same as "screen -ls", but removes destroyed sessions instead of marking them as `dead'. An unreachable session is considered dead, when its name matches either the name of the local host, or the explicitly given parameter, if any. See the -r flag for a description how to construct matches.
- -x
- Attach to a not detached screen session. (Multi display mode). Screen refuses to attach from within itself. But when cascading multiple screens, loops are not detected; take care.
- -X
- Send the specified command to a running screen session. You may use the -S option to specify the screen session if you have several screen sessions running. You can use the -d or -r option to tell screen to look only for attached or detached screen sessions. Note that this command doesn't work if the session is password protected.
- -4
- Resolve hostnames only to IPv4 addresses.
- -6
- Resolve hostnames only to IPv6 addresses.
DEFAULT KEY BINDINGS¶
As mentioned, each screen command consists of a "C-a" followed by one other character. For your convenience, all commands that are bound to lower-case letters are also bound to their control character counterparts (with the exception of "C-a a"; see below), thus, "C-a c" as well as "C-a C-c" can be used to create a window. See section "CUSTOMIZATION" for a description of the command.- The following table shows the default key bindings:
- C-a ' (select)
- Prompt for a window name or number to switch to.
- C-a " (windowlist -b)
- Present a list of all windows for selection.
- C-a 0 (select 0)
- … …
- C-a 9 (select 9)
- C-a - (select -)
- Switch to window number 0 - 9, or to the blank window.
- C-a tab (focus)
- Switch the input focus to the next region. See also split, remove, only.
- 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 command becomes "]]".
- C-a a (meta)
- Send the command character (C-a) to window. See escape command.
- C-a A (title)
- Allow the user to enter a name for the current window.
- C-a b
- C-a C-b (break)
- Send a break to window.
- C-a B (pow_break)
- Reopen the terminal line and send a break.
- C-a c
- C-a C-c (screen)
- Create a new window with a shell and switch to that window.
- C-a C (clear)
- Clear the screen.
- C-a d
- C-a C-d (detach)
- Detach screen from this terminal.
- C-a D D (pow_detach)
- Detach and logout.
- C-a f
- C-a C-f (flow)
- Toggle flow on, off or auto.
- C-a F (fit)
- Resize the window to the current region size.
- 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 current window to the file "screenlog.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 configured to update the utmp database.
- C-a m
- C-a C-m (lastmsg)
- Repeat the last message displayed in the message line.
- C-a M (monitor)
- Toggles monitoring of the current window.
- C-a space
- C-a n
- C-a C-n (next)
- Switch to the next window.
- C-a N (number)
- Show the number (and title) of the current window.
- C-a backspace
- C-a C-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 Q (only)
- Delete all regions but the current one. See also split, remove, focus.
- C-a r
- C-a C-r (wrap)
- Toggle the current window's line-wrap setting (turn the current window's automatic margins on and off).
- C-a s
- C-a C-s (xoff)
- Send a control-s to the current window.
- C-a S (split)
- Split the current region horizontally into two new ones. See also only, remove, focus.
- C-a t
- C-a C-t (time)
- Show system information.
- C-a v (version)
- Display the version and compilation date.
- C-a C-v (digraph)
- Enter digraph.
- C-a w
- C-a C-w (windows)
- Show a list of window.
- C-a W (width)
- Toggle 80/132 columns.
- C-a x
- C-a C-x (lockscreen)
- Lock this terminal.
- C-a X (remove)
- Kill the current region. See also split, only, focus.
- C-a z
- C-a C-z (suspend)
- Suspend screen. Your system must support BSD-style job-control.
- C-a Z (reset)
- Reset the virtual terminal to its "power-on" values.
- C-a . (dumptermcap)
- Write out a ".termcap" file.
- C-a ? (help)
- Show key bindings.
- C-a \ (quit)
- Kill all windows and terminate screen.
- C-a : (colon)
- Enter command line mode.
- C-a [
- C-a C-[
- C-a esc (copy)
- Enter copy/scrollback mode.
- C-a C-]
- C-a ] (paste .)
- Write the contents of the paste buffer to the stdin queue of the current window.
- C-a {
- C-a } (history)
- Copy and paste a previous (command) line.
- C-a > (writebuf)
- Write paste buffer to a file.
- C-a < (readbuf)
- Reads the screen-exchange file into the paste buffer.
- C-a = (removebuf)
- Removes the file used by C-a < and C-a >.
- C-a , (license)
- Shows where screen comes from, where it went to and why you can use it.
- C-a _ (silence)
- Start/stop monitoring the current window for inactivity.
- C-a | (split -v)
- Split the current region vertically into two new ones.
- C-a * (displays)
- Show a listing of all currently attached displays.
CUSTOMIZATION¶
The "socket directory" defaults either to $HOME/.screen or simply to /tmp/screens or preferably to /var/run/screen 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 700 directory in the environment variable $SCREENDIR. When screen is invoked, it executes initialization commands from the files "/etc/screenrc" and ".screenrc" in the user's home directory. These are the "programmer's defaults" that can be overridden in the following ways: for the global screenrc file screen searches for the environment variable $SYSSCREENRC (this override feature may be disabled at compile-time). The user specific screenrc file is searched in $SCREENRC, then $HOME/.screenrc. The command line option -c takes precedence over the above user screenrc files. Commands in these files are used to set options, bind functions to keys, and to automatically establish one or more windows at the beginning of your screen session. Commands are listed one per line, with empty lines being ignored. A command's arguments are separated by tabs or spaces, and may be surrounded by single or double quotes. A `#' turns the rest of the line into a comment, except in quotes. Unintelligible lines are warned about and ignored. Commands may contain references to environment variables. The syntax is the shell-like "$VAR " or "${VAR}". Note that this causes incompatibility with previous screen versions, as now the '$'-character has to be protected with '\' if no variable substitution shall be performed. A string in single-quotes is also protected from variable substitution. Two configuration files are shipped as examples with your screen distribution: "etc/screenrc" and "etc/etcscreenrc". They contain a number of useful examples for various commands. 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 current settings. The following commands are available: acladd usernames [crypted-pw]- attrcolor b "R"
- attrcolor u "-u b"
- attrcolor b ".I"
- attrcolor i "+b"
bind ' ' windows bind ^k bind k bind K kill bind ^f screen telnet foobar bind \033 screen -ln -t root -h 1000 9 suwould 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"). The next three lines remove the default kill binding from "C-a C-k" and "C-a k". "C-a K" is then bound to the kill command. Then it binds "C-f" to the command "create a window with a TELNET connection to foobar", and bind "escape" to the command that creates an non-login window with a.k.a. "root" in slot #9, with a superuser shell and a scrollback buffer of 1000 lines.
bind -c demo1 0 select 10 bind -c demo1 1 select 11 bind -c demo1 2 select 12 bindkey "^B" command -c demo1makes "C-b 0" select window 10, "C-b 1" window 11, etc.
bind -c demo2 0 select 10 bind -c demo2 1 select 11 bind -c demo2 2 select 12 bind - command -c demo2makes "C-a - 0" select window 10, "C-a - 1" window 11, etc. 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 programmed 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.
bindkey -dShow all of the default key bindings. The application mode entries are marked with [A].
bindkey -k k1 select 1Make the "F1" key switch to window one.
bindkey -t foo stuff barfooMake "foo" an abbreviation of the word "barfoo". Timeout is disabled so that users can type slowly.
bindkey "\024" mapdefaultThis key-binding makes "^T" an escape character for key-bindings. If you did the above "stuff barfoo" binding, you can enter the word "foo" by typing "^Tfoo". If you want to insert a "^T" you have to press the key twice (i.e., escape the escape binding).
bindkey -k F1 commandMake the F11 (not F1!) key an alternative screen escape (besides ^A). break [duration] Send a break signal for duration*0.25 seconds to this window. For non-Posix systems the time interval may be rounded up to full seconds. Most useful if a character device is attached to the window rather than a shell process (See also chapter "WINDOW TYPES"). The maximum duration of a break signal is limited to 15 seconds. blanker Activate the screen blanker. First the screen is cleared. If no blanker program is defined, the cursor is turned off, otherwise, the program is started and it's output is written to the screen. The screen blanker is killed with the first keypress, the read key is discarded.
C-a : bufferfile /etc/passwd C-a < C-a ] C-a : bufferfilec1 [on|off] Change c1 code processing. "C1 on" tells screen to treat the input characters between 128 and 159 as control functions. Such an 8-bit code is normally the same as ESC followed by the corresponding 7-bit code. The default setting is to process c1 codes and can be changed with the "defc1" command. Users with fonts that have usable characters in the c1 positions may want to turn this off. caption always|splitonly [string]
h, C-h, or left arrow move the cursor left.
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. When no parameter is given, the state is toggled. debug on|off Turns runtime debugging on or off. If screen has been compiled with option -DDEBUG debugging available and is turned on per default. Note that this command only affects debugging output from the main "SCREEN" process correctly. Debug output from attacher processes can only be turned off once and forever. defc1 on|off Same as the c1 command except that the default setting for new windows is changed. Initial setting is `on'. defautonuke on|off Same as the autonuke command except that the default setting for new displays is changed. Initial setting is `off'. Note that you can use the special `AN' terminal capability if you want to have a dependency on the terminal type. defbce on|off Same as the bce command except that the default setting for new windows is changed. Initial setting is `off'. defbreaktype [tcsendbreak|TIOCSBRK |TCSBRK] Choose one of the available methods of generating a break signal for terminal devices. 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-dependent, this also differs between serial board drivers. Calling "defbreaktype" with no parameter displays the current setting. 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 misinterpretation of program generated hardstatus lines impossible. If the parameter status is omitted, the current default string is displayed. Per default the hardstatus line of new windows is empty. defencoding enc Same as the encoding command except that the default setting for new windows is changed. Initial setting is the encoding taken from the terminal. deflog on|off Same as the log command except that the default setting for new windows is changed. Initial setting is `off'. deflogin on|off Same as the login command except that the default setting for new windows is changed. This is initialized with `on' 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 setting for new windows is changed. Initial setting is `off'. defmousetrack on|off Same as the mousetrack command except that the default setting for new windows is changed. Initial setting is `off'. defnonblock on|off|numsecs Same as the nonblock command except that the default setting for displays is changed. Initial setting is `off'. defobuflimit limit Same as the obuflimit command except that the default setting for new displays is changed. Initial setting is 256 bytes. Note that you can use the special 'OL' terminal capability if you want to have a dependency on the terminal type. defscrollback num Same as the scrollback command except that the default setting for new windows is changed. Initial setting is 100. defshell command Synonym to the shell .screenrc command. See there. defsilence on|off Same as the silence command except that the default setting for new windows is changed. Initial setting is `off'. defslowpaste msec" Same as the slowpaste command except that the default setting for new windows is changed. Initial setting is 0 milliseconds, meaning `off'. defutf8 on|off Same as the utf8 command except that the default setting for new windows is changed. Initial setting is `on' if screen was started with "-U", otherwise `off'. 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 setting for new windows is changed. Initially writelocks will off. defzombie [keys] Synonym to the zombie command. Both currently change the default. See there. detach [-h] 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"). The -h option tells screen to immediately close the connection to the terminal ("hangup"). dinfo Show what screen thinks about your terminal. Useful if you want to know why features like color or the alternate charset don't work. displays Shows a tabular listing of all currently connected user front-ends (displays). This is most useful for multiuser sessions. The following keys can be used in displays list:
k, C-p, or up Move up one line.
- xterm 80x42 jnweiger@/dev/ttyp4 0(m11) &rWx
(A) (B) (C) (D) (E) (F)(G) (H)(I)
(1st character)
‘-’ : no read
‘r’ : read
‘R’ : read only due to foreign wlock
(2nd character)
‘-’ : no write
‘.’ : write suppressed by foreign wlock
‘w’ : write
‘W’ : own wlock
(3rd character)
‘-’ : no execute
‘x’ : execute "Displays" needs a region size of at least 10 characters wide and 5 characters high in order to display. digraph [preset[unicode-value]] 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 characters (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. When a non-zero unicode-value is specified, a new digraph is created with the specified preset. The digraph is unset if a zero value is provided for the unicode-value. 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 window. 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 /etc/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. encoding enc [enc] Tell screen how to interpret the input/output. The first argument sets the encoding of the current window. Each window can emulate a different encoding. The optional second parameter overwrites the encoding of the connected terminal. It should never be needed as screen uses the locale setting to detect the encoding. There is also a way to select a terminal encoding depending on the terminal type by using the "KJ" termcap entry. Supported encodings are eucJP, SJIS, eucKR, eucCN, Big5, GBK, KOI8-R, CP1251, UTF-8, ISO8859-2, ISO8859-3, ISO8859-4, ISO8859-5, ISO8859-6, ISO8859-7, ISO8859-8, ISO8859-9, ISO8859-10, ISO8859-15, jis. See also "defencoding", which changes the default setting of a new window. escape xy Set the command character to x and the character generating a literal command character (by triggering the "meta" command) to y (similar to 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". eval command1 [command2 …] Parses and executes each argument as separate command. exec [[fdpat] newcommand [args …]] Run a unix subprocess (specified by an executable path newcommand and its optional arguments) in the current window. The flow of data between newcommands stdin/stdout/stderr, the process originally started in the window (let us call it "application-process") and screen itself (window) is controlled by the file descriptor pattern fdpat. This pattern is basically a three character sequence representing stdin, stdout and stderr of newcommand. A dot (.) connects the file descriptor to screen. An exclamation mark (!) causes the file descriptor to be connected to the application-process. A colon (:) combines both. User input will go to newcommand unless newcommand receives the application-process' output (fdpats first character is `!' or `:') or a pipe symbol (|) is added (as a fourth character) to the end of fdpat.
- exec … /bin/sh
- exec !.. stty 19200
- exec !..| less
- !:sed -n s/.*Error.*/\007/p
bind j focus down bind k focus up bind t focus top bind b focus bottomNote that k is traditionally bound to the kill command. focusminsize [ ( width|max|_ ) ( height|max|_ ) ] This forces any currently selected region to be automatically resized at least a certain width and height. All other surrounding regions will be resized in order to accommodate. This constraint follows everytime the "focus" command is used. The "resize" command can be used to increase either dimension of a region, but never below what is set with "focusminsize". The underscore `_' is a synonym for max. Setting a width and height of `0 0' (zero zero) will undo any constraints and allow for manual resizing. Without any parameters, the minimum width and height is shown. gr [on|off] Turn GR charset switching on/off. Whenever screen sees an input character with the 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. group [grouptitle] Change or show the group the current window belongs to. Windows can be moved around between different groups by specifying the name of the destination group. Without specifying a group, the title of the current group is displayed. hardcopy [-h] [file] 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. See below. If the option -h is specified, dump also the contents of the scrollback buffer. 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]
+flow automatic flow control, currently on. -flow automatic flow control, currently off. +(+)flow flow control enabled. Agrees with automatic control. -(+)flow flow control disabled. Disagrees with automatic control. +(-)flow flow control enabled. Disagrees with automatic control. -(-)flow flow control disabled. Agrees with automatic control.The current line wrap setting (`+wrap' indicates enabled, `-wrap' not) is also shown. The flags `ins', `org', `app', `log', `mon' or `nored' are displayed when the window is in insert mode, origin mode, application-keypad mode, has output logging, activity monitoring or partial redraw enabled. The currently active character set ( G0, G1, G2, or G3) and in square brackets the terminal character sets that are currently designated as G0 through G3 is shown. If the window is in UTF-8 mode, the string "UTF-8" is shown instead. Additional modes depending on the type of the window are displayed at the end of the status line (See also chapter "WINDOW TYPES").
C-a : layout dump /home/user/.screenrcwill save or append the layout to the user's .screenrc file. 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.
C-a : readreg p /etc/passwd C-a : paste predisplay Redisplay the current window. Needed to get a full redisplay when in partial redraw mode. register [-e encoding] key string Save the specified string to the register key. The encoding of the string can be specified via the -e option. See also the "paste" command. remove Kill the current region. This is a no-op if there is only one region. removebuf Unlinks the screen-exchange file used by the commands "writebuf" and "readbuf". rendition bell | monitor | silence | so attr [color] Change the way screen renders the titles of windows that have monitor or bell flags set in caption or hardstatus or windowlist. See the "STRING ESCAPES" chapter for the syntax of the modifiers. The default for monitor is currently "=b " (bold, active colors), for bell "=ub " (underline, bold and active colors), and "=u " for silence. reset Reset the virtual terminal to its "power-on" values. Useful when strange settings (like scroll regions or graphics character set) are left over from an application. resize Resize the current region. The space will be removed from or added to the region below or if there's not enough space from the region above.
- resize +N increase current region height by N
- resize -N decrease current region height by N
- resize N set current region height to N
- resize = make all windows equally high
- resize max maximize current region height
- resize min minimize current region height
# example for .screenrc: screen 1 screen -fn -t foobar -L 2 telnet foobarscreen 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) and will write a logfile ("screenlog.2") of the telnet session. 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.
- termcap xterm* LP:hs@
- termcap vt* LP
- termcap vt100 "" l0=PF1:l1=PF2:l2=PF3:l3=PF4
- termcap h19|z19 am@:im=\E@:ei=\EO dc=\E[P
k, C-p, or up Move up one line.
The table format can be changed with the string and title option, the title is displayed as table heading, while the lines are made by using the string setting. The default setting is "Num Name%=Flags" for the title and "%3n %t%=%f" for the lines. See the "STRING ESCAPES" chapter for more codes (e.g. color settings). "Windowlist" needs a region size of at least 10 characters wide and 6 characters high in order to display. windows Uses the message line to display a list of all the windows. Each window is listed by number with the name of process that has been started in the window (or its title); the current window is marked with a `*'; the previous window is marked with a `-'; all the windows that are "logged in" are marked with a `$'; a background window that has received a bell is marked with a `!'; a background window that is being monitored and has had activity occur is marked with an `@'; a window which has output logging turned on is marked with `(L)'; windows occupied by other users are marked with `&'; windows in the zombie state are marked with `Z'. If this list is too long to fit on the terminal's status line only the portion around the current window is displayed. wrap [on|off] Sets the line-wrap setting for the current window. When line-wrap is on, the second consecutive printable character output at the last column of a line will wrap to the start of the following line. As an added feature, backspace (^H) will also wrap through the left margin to the previous line. Default is `on'. Without any options, the state of wrap is toggled. writebuf [-e encoding] [filename] Writes the contents of the paste buffer to the specified file, or the public accessible screen-exchange file if no filename is given. This is thought of as a primitive means of communication between screen users on the same host. If an encoding is specified the paste buffer is recoded on the fly to match the encoding. The filename can be set with the bufferfile command and defaults to "/tmp/screen-exchange". writelock [on|off|auto] In addition to access control lists, not all users may be able to write to the same window at once. Per default, writelock is in `auto' mode and grants exclusive input permission to the user who is the first to switch to the particular window. When he leaves the window, other users may obtain the writelock (automatically). The writelock of the current window is 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
THE MESSAGE LINE¶
Screen displays informational messages and other diagnostics in a message line. While this line is distributed to appear at the bottom of the screen, it can be defined to appear at the top of the screen during compilation. If your terminal has a status line defined in its termcap, screen will use this for displaying its messages, otherwise a line of the current screen will be temporarily overwritten and output will be momentarily interrupted. The message line is automatically removed after a few seconds delay, but it can also be removed early (on terminals without a status line) by beginning to type. The message line facility can be used by an application running in the current window by means of the ANSI Privacy message control sequence. For instance, from within the shell, try something like:- echo '<esc>^Hello world from window '$WINDOW'<esc>\\'
WINDOW TYPES¶
Screen provides three different window types. New windows are created with screen's screen command (see also the entry in chapter "CUSTOMIZATION"). The first parameter to the screen command defines which type of window is created. The different window types are all special cases of the normal type. They have been added in order to allow screen to be used efficiently as a console multiplexer with 100 or more windows.- •
- The normal window contains a shell (default, if no parameter is given) or any other system command that could be executed from a shell (e.g. slogin, etc…)
- •
- If a tty (character special device) name (e.g. "/dev/ttya") is specified as the first parameter, then the window is directly connected to this device. This window type is similar to "screen cu -l /dev/ttya". Read and write access is required on the device node, an exclusive open is attempted on the node to mark the connection line as busy. An optional parameter is allowed consisting of a comma separated list of flags in the notation used by stty(1):
- <baud_rate>
- Usually 300, 1200, 9600 or 19200. This affects transmission as well as receive speed.
- cs8 or cs7
- Specify the transmission of eight (or seven) bits per byte.
- ixon or -ixon
- Enables (or disables) software flow-control (CTRL-S/CTRL-Q) for sending data.
- ixoff or -ixoff
- Enables (or disables) software flow-control for receiving data.
- istrip or -istrip
- Clear (or keep) the eight bit in each received byte.
- •
- If the first parameter is "//telnet", the second parameter is
expected to be a host name, and an optional third parameter may specify a
TCP port number (default decimal 23). Screen will connect to a server
listening on the remote host and use the telnet protocol to communicate
with that server.
- b
- BINARY. The connection is in binary mode.
- e
- ECHO. Local echo is disabled.
- c
- SGA. The connection is in `character mode' (default: `line mode').
- t
- TTYPE. The terminal type has been requested by the remote host. Screen sends the name "screen" unless instructed otherwise (see also the command `term').
- w
- NAWS. The remote site is notified about window size changes.
- f
- LFLOW. The remote host will send flow control information. (Ignored at the moment.)
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
- E
- sets %? to true if the escape character has been pressed.
- f
- flags of the window, see "windows" for meanings of the various flags
- 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
- P
- sets %? to true if the current region is in copy/paste mode
- S
- session name
- s
- seconds
- t
- window title
- u
- all other users on this window
- w
- all window numbers and names. With '-' qualifier: 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.
- +
- 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
- d
- dim
- u
- underline
- b
- bold
- r
- reverse
- s
- standout
- B
- blinking
- k
- black
- r
- red
- g
- green
- y
- yellow
- b
- blue
- m
- magenta
- c
- cyan
- w
- white
- d
- default color
- .
- leave color unchanged
- set color to bright green
- use bold red
- clear all attributes, write in default color on yellow background.
- %-Lw%{= BW}%50>%n%f* %t%{-}%+Lw%<
- The available windows centered at the current window 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".
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 characters are used to immediately pause the output of the current window. You can still send these characters to the current program, but you must use the appropriate two-character screen commands (typically "C-a q" (xon) and "C-a s" (xoff)). The xon/xoff commands are also useful for typing C-s and C-q past a terminal that intercepts these characters. Each window has an initial flow-control value set with either the -f option or the "defflow" .screenrc command. Per default the windows are set to automatic flow-switching. It can then be toggled between the three states 'fixed on', 'fixed off' and 'automatic' interactively with the "flow" command bound to "C-a f". The automatic flow-switching mode deals with flow control using the TIOCPKT mode (like "rlogin" does). If the tty driver does not support TIOCPKT, screen tries to find out the right mode based on the current setting of the application keypad - when it is enabled, flow-control is turned off and visa versa. Of course, you can still manipulate flow-control manually when needed. If you're running with flow-control enabled and find that pressing the interrupt key (usually C-c) does not interrupt the display until another 6-8 lines have scrolled by, try running screen with the "interrupt" option (add the "interrupt" flag to the "flow" command in your .screenrc, or use the -i command-line option). This causes the output that screen has accumulated from the interrupted program to be flushed. One disadvantage is that the virtual terminal's memory contains the non-flushed version of the output, which in rare cases can cause minor inaccuracies in the output. For example, if you switch screens and return, or update the screen with "C-a l" you would see the version of the output you would have gotten without "interrupt" being on. Also, you might need to turn off flow-control (or use auto-flow mode to turn it off automatically) when running a program that expects you to type the interrupt character as input, as it is possible to interrupt the output of the virtual terminal to your physical terminal when flow-control is enabled. If this happens, a simple refresh of the screen with "C-a l" will restore it. Give each mode a try, and use whichever mode you find more comfortable.TITLES (naming windows)¶
You can customize each window's name in the window display (viewed with the "windows" command (C-a w)) by setting it with one of the title commands. Normally the name displayed is the actual command name of the program created in the window. However, it is sometimes useful to distinguish various programs of the same name or to change the name on-the-fly to reflect the current state of the window. The default name for all shell windows can be set with the "shelltitle" command in the .screenrc file, while all other windows are created with a "screen" command and thus can have their name set with the -t option. Interactively, there is the title-string escape-sequence (<esc>k name<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 current command running in the window to the end of the window's shell name (e.g. " name:cmd"). Otherwise the current command name supersedes the shell name while it is running. Here's how it works: you must modify your shell prompt to output a null title-escape-sequence (<esc>k<esc>\) as a part of your prompt. The last part of your prompt must be the same as the string you specified for the search portion of the title. Once this is set up, screen will use the title-escape-sequence to clear the previous command name and get ready for the next command. Then, when a newline is received from the shell, a search is made for the end of the prompt. If found, it will grab the first word after the matched string and use it as the command name. If the 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
shelltitle '> |csh' screen 1These commands would start a shell with the given shelltitle. 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
- bind R screen -t '% |root:' su
% !em emacs file.cHere 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). One thing to keep in mind when adding a null title-escape-sequence to your prompt is that some shells (like the csh) count all the non-control characters as part of the prompt's length. If these invisible characters aren't a multiple of 8 then backspacing over a tab will result in an incorrect display. One way to get around this is to use a prompt like this:
- set prompt='^[[0000m^[k^[\% '
- PROMPT_COMMAND='printf "\033k\033\134"'
THE VIRTUAL TERMINAL¶
Each window in a screen session emulates a VT100 terminal, with some extra functions added. The VT100 emulator is hard-coded, no other terminal types can be emulated.- 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
- ESC Pn p
- Cursor Visibility (97801)
- Pn = 6
- Invisible
- 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 interpretation.
- ESC _ (A)
- Application Program Command (Hardstatus)
- ESC ] 0 ; string ^G (A)
- Operating System Command (Hardstatus, xterm title hack)
- ESC ] 83 ; cmd ^G (A)
- Execute screen command. This only works if multi-user support is compiled into screen. The pseudo-user ":window:" is used to check the access control list. Use "addacl :window: -rwx #?" to create a user with no rights and allow only the needed commands.
- Control-N (A)
- Lock Shift G1 (SO)
- Control-O (A)
- Lock Shift G0 (SI)
- ESC n (A)
- Lock Shift G2
- ESC o (A)
- Lock Shift G3
- ESC N (A)
- Single Shift G2
- ESC O (A)
- Single Shift G3
- ESC ( Pcs (A)
- Designate character set as G0
- ESC ) Pcs (A)
- Designate character set as G1
- ESC * Pcs (A)
- Designate character set as G2
- ESC + Pcs (A)
- Designate character set as G3
- ESC [ Pn ; Pn H
- Direct Cursor Addressing
- ESC [ Pn ; Pn f
- same as above
- ESC [ Pn J
- Erase in Display
- Pn = None or 0
- From Cursor to End of Screen
- 1
- From Beginning of Screen to Cursor
- 2
- Entire Screen
- ESC [ Pn K
- Erase in Line
- Pn = None or 0
- From Cursor to End of Line
- 1
- From Beginning of Line to Cursor
- 2
- Entire Line
- ESC [ Pn X
- Erase character
- ESC [ Pn A
- Cursor Up
- ESC [ Pn B
- Cursor Down
- ESC [ Pn C
- Cursor Right
- ESC [ Pn D
- Cursor Left
- ESC [ Pn E
- Cursor next line
- ESC [ Pn F
- Cursor previous line
- ESC [ Pn G
- Cursor horizontal position
- ESC [ Pn `
- same as above
- ESC [ Pn d
- Cursor vertical position
- ESC [ Ps ;…; Ps m
- Select Graphic Rendition
- Ps = None or 0
- Default Rendition
- 1
- Bold
- 2 (A)
- Faint
- 3 (A)
- Standout Mode (ANSI: Italicized)
- 4
- Underlined
- 5
- Blinking
- 7
- Negative Image
- 22 (A)
- Normal Intensity
- 23 (A)
- Standout Mode off (ANSI: Italicized off)
- 24 (A)
- Not Underlined
- 25 (A)
- Not Blinking
- 27 (A)
- Positive Image
- 30 (A)
- Foreground Black
- 31 (A)
- Foreground Red
- 32 (A)
- Foreground Green
- 33 (A)
- Foreground Yellow
- 34 (A)
- Foreground Blue
- 35 (A)
- Foreground Magenta
- 36 (A)
- Foreground Cyan
- 37 (A)
- Foreground White
- 39 (A)
- Foreground Default
- 40 (A)
- Background Black
- …
- …
- 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 [ Pn ^
- same as above
- ESC [ Ps ;…; Ps h
- Set Mode
- ESC [ Ps ;…; Ps l
- Reset Mode
- Ps = 4 (A)
- Insert Mode
- 20 (A)
- Automatic Linefeed Mode
- 34
- Normal Cursor Visibility
- ?1 (V)
- Application Cursor Keys
- ?3 (V)
- Change Terminal Width to 132 columns
- ?5 (V)
- Reverse Video
- ?6 (V)
- Origin Mode
- ?7 (V)
- Wrap Mode
- ?9
- X10 mouse tracking
- ?25 (V)
- Visible Cursor
- ?47
- Alternate Screen (old xterm code)
- ?1000 (V)
- VT200 mouse tracking
- ?1047
- Alternate Screen (new xterm code)
- ?1049
- Alternate Screen (new xterm code)
- ESC [ 5 i (A)
- Start relay to printer (ANSI Media Copy)
- ESC [ 4 i (A)
- Stop relay to printer (ANSI Media Copy)
- ESC [ 8 ; Ph ; Pw t
- Resize the window to `Ph' lines and `Pw' columns (SunView special)
- ESC [ c
- Send VT100 Identification String
- ESC [ x
- Send Terminal Parameter Report
- ESC [ > c
- Send VT220 Secondary Device Attributes String
- ESC [ 6 n
- Send Cursor Position Report
INPUT TRANSLATION¶
In order to do a full VT100 emulation screen has to detect that a sequence of characters in the input stream was generated 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 possible to map arbitrary commands on arbitrary sequences of characters. For standard 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 generated by a keypress can change after a reattach from a different terminal type, it is possible to bind commands to the termcap name of the keys. Screen will insert the correct binding after each reattach. See the bindkey command for further details on the syntax and examples. Here is the table of the default key bindings. (A) means that the command is executed if the keyboard is switched into application mode.Key name Termcap name Command Cursor up ku stuff \033[A stuff \033OA (A) Cursor down kd stuff \033[B stuff \033OB (A) Cursor right kr stuff \033[C stuff \033OC (A) Cursor left kl stuff \033[D stuff \033OD (A) Function key 0 k0 stuff \033[10~ Function key 1 k1 stuff \033OP Function key 2 k2 stuff \033OQ Function key 3 k3 stuff \033OR Function key 4 k4 stuff \033OS Function key 5 k5 stuff \033[15~ Function key 6 k6 stuff \033[17~ Function key 7 k7 stuff \033[18~ Function key 8 k8 stuff \033[19~ Function key 9 k9 stuff \033[20~ Function key 10 k; stuff \033[21~ Function key 11 F1 stuff \033[23~ Function key 12 F2 stuff \033[24~ 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 \033Oy (A) Keypad + f+ stuff + 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 termcap(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 margins'). Note that this capability is obsolete because screen uses the standard 'xn' instead.
- Z0 (str)
- Change width to 132 columns.
- Z1 (str)
- Change width to 80 columns.
- WS (str)
- Resize display. This capability has the desired width and height as arguments. SunView(tm) example: '\E[8;%d;%dt'.
- NF (bool)
- Terminal doesn't need flow control. Send ^S and ^Q direct to the application. Same as 'flow off'. The opposite of this capability is 'nx'.
- G0 (bool)
- Terminal can deal with ISO 2022 font selection sequences.
- S0 (str)
- Switch charset 'G0' to the specified charset. Default is '\E(%.'.
- E0 (str)
- Switch charset 'G0' back to standard charset. Default is '\E(B'.
- C0 (str)
- Use the string as a conversion table for font '0'. See the 'ac' capability for more details.
- CS (str)
- Switch cursor-keys to application mode.
- CE (str)
- Switch cursor-keys back to normal mode.
- AN (bool)
- Turn on autonuke. See the 'autonuke' command for more details.
- OL (num)
- Set the output buffer limit. See the 'obuflimit' command for more details.
- KJ (str)
- Set the encoding of the terminal. See the 'encoding' command 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. More details follow in the next section.
- 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).
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'.
ENVIRONMENT¶
- 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"). See also "shell" .screenrc command.
- STY
- Alternate socket name.
- SYSSCREENRC
- Alternate system screenrc file.
- TERM
- Terminal name.
- TERMCAP
- Terminal description.
- WINDOW
- Window number of a window (at creation time).
FILES¶
- …/screen-4.?.??/etc/screenrc
- …/screen-4.?.??/etc/etcscreenrc
- Examples in the screen distribution package for private and global initialization files.
- $SYSSCREENRC
- /etc/screenrc
- screen initialization commands
- $SCREENRC
- $HOME/.screenrc
- Read in after /etc/screenrc
- $SCREENDIR/S-<login>
- /var/run/screen/S-<login>
- Socket directories (default)
- /usr/tmp/screens/S-<login>
- Alternate socket directories.
- <socket directory>/.termcap
- Written by the "termcap" output function
- /usr/tmp/screens/screen-exchange
- or
- /tmp/screen-exchange
- screen `interprocess communication buffer'
- hardcopy.[0-9]
- Screen images created by the hardcopy function
- screenlog.[0-9]
- Output log files created by the log function
- /usr/lib/terminfo/?/*
- or
- /etc/termcap
- Terminal capability databases
- /var/run/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 Juergen Weigert, Michael Schroeder, Micah Cowan and Sadrul Habib Chowdhury.COPYLEFT¶
Copyright (c) 2010 Juergen Weigert (jnweiger@immd4.informatik.uni-erlangen.de) Sadrul Habib Chowdhury (sadrul@users.sourceforge.net) Copyright (c) 2008, 2009 Juergen Weigert (jnweiger@immd4.informatik.uni-erlangen.de) Michael Schroeder (mlschroe@immd4.informatik.uni-erlangen.de) Micah Cowan (micah@cowan.name) Sadrul Habib Chowdhury (sadrul@users.sourceforge.net) Copyright (C) 1993-2003 Juergen Weigert (jnweiger@immd4.informatik.uni-erlangen.de) Michael Schroeder (mlschroe@immd4.informatik.uni-erlangen.de) Copyright (C) 1987 Oliver LaumannThis program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version. This program is distributed in the hope that it will be 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 Temple 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 (mrg@eterna.com.au), Christopher Williams (cgw@pobox.com), Matt Mosley (mattm@access.digex.net), Gregory Neil Shapiro (gshapiro@wpi.WPI.EDU), Johannes Zellner (johannes@zellner.org), Pablo Averbuj (pablo@averbuj.com).
VERSION¶
This is version 4.1.0. 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.AVAILABILITY¶
The latest official release of screen available via anonymous ftp from gnudist.gnu.org, nic.funet.fi or any other GNU distribution site. The home site of screen is ftp.uni-erlangen.de, 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.BUGS¶
- •
- `dm' (delete mode) and `xs' are not handled correctly (they are ignored). `xn' is treated as a magic-margin indicator.
- •
- Screen has no clue about double-high or double-wide characters. But this is the only area where vttest is allowed to fail.
- •
- It is not possible to change the environment variable $TERMCAP when reattaching under a different terminal type.
- •
- The support of terminfo based systems is very limited. Adding extra capabilities to $TERMCAP may not have any effects.
- •
- Screen does not make use of hardware tabs.
- •
- Screen must be installed as set-uid with owner root 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 "/var/run/utmp".
- •
- Entries in "/var/run/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 is configured to send a HANGUP signal. To detach 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 user's 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.
- •
- Send bug-reports, fixes, enhancements, t-shirts, money, beer & pizza to screen@uni-erlangen.de.
Aug 2003 | 4th Berkeley Distribution |