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   screen    ( 1 )

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CUSTOMIZATION

The "socket directory" defaults either to $HOME/.screen or simply to /tmp/screens or preferably to /usr/local/screens chosen at compile-time. If screen is installed setuid-root, then the administrator should compile screen with an adequate (not NFS mounted) socket directory. If screen is not running setuid-root, the user can specify any mode 700 directory in the environment variable $SCREENDIR.

When screen is invoked, it executes initialization commands from the files "/usr/local/etc/screenrc" and ".screenrc" in the user's home directory. These are the "programmer's defaults" that can be overridden in the following ways: for the global screenrc file screen searches for the environment variable $SYSTEM_SCREENRC (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]

addacl usernames

Enable users to fully access this screen session. Usernames can be one user or a comma separated list of users. This command enables to attach to the screen session and performs the equivalent of `aclchg usernames +rwx "#?"'. executed. To add a user with restricted access, use the `aclchg' command below. If an optional second parameter is supplied, it should be a crypted password for the named user(s). `Addacl' is a synonym to `acladd'. Multi user mode only.

aclchg usernames permbits list

chacl usernames permbits list

Change permissions for a comma separated list of users. Permission bits are represented as `r', `w' and `x'. Prefixing `+' grants the permission, `-' removes it. The third parameter is a comma separated list of commands and/or windows (specified either by number or title). The special list `#' refers to all windows, `?' to all commands. if usernames consists of a single `*', all known users are affected.

A command can be executed when the user has the `x' bit for it. The user can type input to a window when he has its `w' bit set and no other user obtains a writelock for this window. Other bits are currently ignored. To withdraw the writelock from another user in window 2: `aclchg username -w+w 2'. To allow read-only access to the session: `aclchg username -w "#"'. As soon as a user's name is known to screen he can attach to the session and (per default) has full permissions for all command and windows. Execution permission for the acl commands, `at' and others should also be removed or the user may be able to regain write permission. Rights of the special username nobody cannot be changed (see the "su" command). `Chacl' is a synonym to `aclchg'. Multi user mode only.

acldel username

Remove a user from screen's access control list. If currently attached, all the user's displays are detached from the session. He cannot attach again. Multi user mode only.

aclgrp username [groupname]

Creates groups of users that share common access rights. The name of the group is the username of the group leader. Each member of the group inherits the permissions that are granted to the group leader. That means, if a user fails an access check, another check is made for the group leader. A user is removed from all groups the special value "none" is used for groupname. If the second parameter is omitted all groups the user is in are listed.

aclumask [[ users ] +bits | [ users ] -bits... ]

umask [[ users ] +bits | [ users ] -bits... ]

This specifies the access other users have to windows that will be created by the caller of the command. Users may be no, one or a comma separated list of known usernames. If no users are specified, a list of all currently known users is assumed. Bits is any combination of access control bits allowed defined with the "aclchg" command. The special username "?" predefines the access that not yet known users will be granted to any window initially. The special username "??" predefines the access that not yet known users are granted to any command. Rights of the special username nobody cannot be changed (see the "su" command). `Umask' is a synonym to `aclumask'.

activity message

When any activity occurs in a background window that is being monitored, screen displays a notification in the message line. The notification message can be re-defined by means of the "activity" command. Each occurrence of `%' in message is replaced by the number of the window in which activity has occurred, and each occurrence of `^G' is replaced by the definition for bell in your termcap (usually an audible bell). The default message is

'Activity in window %n'

Note that monitoring is off for all windows by default, but can be altered by use of the "monitor" command (C-a M).

allpartial on|off

If set to on, only the current cursor line is refreshed on window change. This affects all windows and is useful for slow terminal lines. The previous setting of full/partial refresh for each window is restored with "allpartial off". This is a global flag that immediately takes effect on all windows overriding the "partial" settings. It does not change the default redraw behavior of newly created windows.

altscreen on|off

If set to on, "alternate screen" support is enabled in virtual terminals, just like in xterm. Initial setting is `off'.

at [identifier][#|*|%] command [args ... ]

Execute a command at other displays or windows as if it had been entered there. "At" changes the context (the `current window' or `current display' setting) of the 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. Permission is checked for initiator of the "at" command, not for the owners of the affected display(s). Note that the '#' character works as a comment introducer when it is preceded by whitespace. This can be escaped by prefixing 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. "process") require that a display is associated with the target windows. These commands may not work correctly under "at" looping over windows.

attrcolor attrib [attribute/color-modifier]

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 "STRING ESCAPES" chapter 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.

autodetach on|off

Sets whether screen will automatically detach upon hangup, which saves all your running programs until they are resumed with a screen -r command. When turned off, a hangup signal will terminate screen and all the processes it contains. Autodetach is on by default.

autonuke on|off

Sets whether a clear screen sequence should nuke all the output that has not been written to the terminal. See also "obuflimit".

backtick id lifespan autorefresh cmd args...

backtick id

Program the backtick command with the numerical id id. The output of such a command is used for substitution of the "%`" string escape. 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.

bce [on|off]

Change background-color-erase setting. If "bce" is set to on, all characters cleared by an erase/insert/scroll/clear operation will be displayed in the current background color. Otherwise the default background color is used.

bell_msg [message]

When a bell character is sent to a background window, screen displays a notification in the message line. The notification message can be re-defined by this command. Each occurrence of `%' in message is replaced by the number of the window to which a bell has been sent, and each occurrence of `^G' is replaced by the definition for bell in your termcap (usually an audible bell). The default message is

'Bell in window %n'

An empty message can be supplied to the "bell_msg" command to suppress output of a message line (bell_msg ""). Without parameter, the current message is shown.

bind [class] key [command [args]]

Bind a command to a key. By default, most of the commands provided by screen are bound to one or more keys as indicated in the "DEFAULT KEY BINDINGS" section, e.g. the command to create a new window is bound to "C-c" and "c". The "bind" command can be used to redefine the key bindings and to define new bindings. The key argument is either a single character, a two-character sequence of the form "^x" (meaning "C-x"), a backslash followed by an octal number (specifying the ASCII code of the character), or a backslash followed by a second character, such as "\^" or "\\". The argument can also be quoted, if you like. If no further argument is given, any previously established binding for this key is removed. The command argument can be any command listed in this section.

If a command class is specified via the "-c" option, the key is bound for the specified class. Use the "command" command to activate a class. Command classes can be used to create multiple command keys or multi-character bindings.

Some examples:

bind ' ' windows bind ^k bind k bind K kill bind ^f screen telnet foobar bind \033 screen -ln -t root -h 1000 9 su

would bind the space key to the command that displays a list of windows (so that the command usually invoked by "C-a C-w" would also be available as "C-a space"). 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 demo1

makes "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 demo2

makes "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.

If the -d option is given, bindkey modifies the default table, -m changes the copy mode table and with neither option the user table is selected. The argument string is the sequence of characters to which an action is bound. This can either be a fixed string or a termcap keyboard capability name (selectable with the -k option).

Some keys on a VT100 terminal can send a different string if application mode is turned on (e.g the cursor keys). Such keys have two entries in the translation table. You can select the application mode entry by specifying the -a option.

The -t option tells screen not to do inter-character timing. One cannot turn off the timing if a termcap capability is used.

Cmd can be any of screen's commands with an arbitrary number of args. If cmd is omitted the key-binding is removed from the table.

Here are some examples of keyboard bindings:

bindkey -d

Show all of the default key bindings. The application mode entries are marked with [A].

bindkey -k k1 select 1

Make the "F1" key switch to window one.

bindkey -t foo stuff barfoo

Make "foo" an abbreviation of the word "barfoo". Timeout is disabled so that users can type slowly.

bindkey "\024" mapdefault

This 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 command

Make the F11 (not F1!) key an alternative screen escape (besides ^A).

break[duration]

Send a break signal for duration*0.25 seconds to this window. 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.

This command is normally used together with the "idle" command.

blankerprg [program-args]

Defines a blanker program. Disables the blanker program if an empty argument is given. Shows the currently set blanker program if no arguments are given.

breaktype [tcsendbreak|TIOCSBRK|TCSBRK]

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 method for the current window.

bufferfile [exchange-file]

Change the filename used for reading and writing with the paste buffer. If the optional argument to the "bufferfile" command is omitted, the default setting ("/tmp/screen-exchange") is reactivated. The following example will paste the system's password file into the screen window (using the paste buffer, where a copy remains):

C-a : bufferfile /etc/passwd C-a < C-a ] C-a : bufferfile

bumpleft

Swaps window with previous one on window list.

bumpright

Swaps window with next one on window list.

c1 [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 [ top | bottom ] always|splitonly[string]

caption string [string]

This command controls the display of the window captions. Normally a caption is only used if more than one window is shown on the display (split screen mode). But if the type is set to always screen shows a caption even if only one window is displayed. The default is splitonly.

The second form changes the text used for the caption. You can use all escapes from the "STRING ESCAPES" chapter. Screen uses a default of `%3n %t'.

You can mix both forms by providing a string as an additional argument.

You can have the caption displayed either at the top or bottom of the window. The default is bottom.

charset set

Change the current character set slot designation and charset mapping. The first four character of set are treated as charset designators while the fifth and sixth character must be in range '0' to '3' and set the GL/GR charset mapping. On every position a '.' may be used to indicate that the corresponding charset/mapping should not be changed (set is padded to six characters internally by appending '.' chars). New windows have "BBBB02" as default charset, unless a "encoding" command is active. The current setting can be viewed with the "info" command.

chdir [directory]

Change the current directory of screen to the specified directory or, if called without an argument, to your home directory (the value of the environment variable $HOME). All windows that are created by means of the "screen" command from within ".screenrc" or by means of "C-a : screen ..." or "C-a c" use this as their default directory. Without a chdir command, this would be the directory from which screen was invoked.

Hardcopy and log files are always written to the window's default directory, not the current directory of the process running in the window. You can use this command multiple times in your .screenrc to start various windows in different default directories, but the last chdir value will affect all the windows you create interactively.

cjkwidth [ on | off ]

Treat ambiguous width characters as full/half width.

clear

Clears the current window and saves its image to the scrollback buffer.

collapse

Reorders window on window list, removing number gaps between them.

colon [prefix]

Allows you to enter ".screenrc" command lines. Useful for on-the- fly modification of key bindings, specific window creation and changing settings. Note that the "set" keyword no longer exists! Usually commands affect the current window rather than default settings for future windows. Change defaults with commands starting with 'def...'.

If you consider this as the `Ex command mode' of screen, you may regard "C-a esc" (copy mode) as its `Vi command mode'.

command [-c class]

This command has the same effect as typing the screen escape character (^A). It is probably only useful for key bindings. If the "-c" option is given, select the specified command class. See also "bind" and "bindkey".

compacthist [on|off]

This tells screen whether to suppress trailing blank lines when scrolling up text into the history buffer.

console [on|off]

Grabs or un-grabs the machines console output to a window. Note: Only the owner of /dev/console can grab the console output. This command is only available if the machine supports the ioctl TIOCCONS.

copy

Enter copy/scrollback mode. This allows you to copy text from the current window and its history into the paste buffer. In this mode a vi-like `full screen editor' is active: The editor's movement keys are:

──────────────────────────────────────────────────────────────── h, C-h, move the cursor left. left arrow ──────────────────────────────────────────────────────────────── j, C-n, move the cursor down. down arrow ────────────────────────────────────────────────────────────────

k, C-p, move the cursor up. up arrow ──────────────────────────────────────────────────────────────── l ('el'), move the cursor right. right arrow ──────────────────────────────────────────────────────────────── 0 (zero) C-a move to the leftmost column. ──────────────────────────────────────────────────────────────── + and - positions one line up and down. ──────────────────────────────────────────────────────────────── H, M and L move the cursor to the leftmost column of the top, center or bottom line of the window. ──────────────────────────────────────────────────────────────── | moves to the specified absolute column. ──────────────────────────────────────────────────────────────── g or home moves to the beginning of the buffer. ──────────────────────────────────────────────────────────────── G or end moves to the specified absolute line (default: end of buffer). ──────────────────────────────────────────────────────────────── % jumps to the specified percentage of the buffer. ──────────────────────────────────────────────────────────────── ^ or $ move to the leftmost column, to the first or last non-whitespace character on the line. ──────────────────────────────────────────────────────────────── w, b, and e move the cursor word by word. ──────────────────────────────────────────────────────────────── B, E move the cursor WORD by WORD (as in vi). ──────────────────────────────────────────────────────────────── f/F, t/T move the cursor forward/backward to the next occurence of the target. (eg, '3fy' will move the cursor to the 3rd 'y' to the right.) ──────────────────────────────────────────────────────────────── ; and , Repeat the last f/F/t/T command in the same/opposite direction. ──────────────────────────────────────────────────────────────── C-e and C-y scroll the display up/down by one line while preserving the cursor position. ──────────────────────────────────────────────────────────────── C-u and C-d scroll the display up/down by the specified amount of lines while preserving the cursor position. (Default: half screen-full). ──────────────────────────────────────────────────────────────── C-b and C-f scroll the display up/down a full screen. ────────────────────────────────────────────────────────────────

Note: Emacs style movement keys can be customized by a .screenrc command. (E.g. markkeys "h=^B:l=^F:$=^E") There is no simple method for a full emacs-style keymap, as this involves multi- character codes.

Some keys are defined to do mark and replace operations.

The copy range is specified by setting two marks. The text between these marks will be highlighted. Press:

space or enter to set the first or second mark respectively. If mousetrack is set to `on', marks can also be set using left mouse click.

Y and y used to mark one whole line or to mark from start of line.

W marks exactly one word.

Any of these commands can be prefixed with a repeat count number by pressing digits

0..9 which is taken as a repeat count.

Example: "C-a C-[ H 10 j 5 Y" will copy lines 11 to 15 into the paste buffer.

The folllowing search keys are defined:

/ Vi-like search forward.

? Vi-like search backward.

C-a s Emacs style incremental search forward.

C-r Emacs style reverse i-search.

n Find next search pattern.

N Find previous search pattern.

There are however some keys that act differently than in vi. Vi does not allow one to yank rectangular blocks of text, but screen does. Press: c or C to set the left or right margin respectively. If no repeat count is given, both default to the current cursor position.

Example: Try this on a rather full text screen:

"C-a [ M 20 l SPACE c 10 l 5 j C SPACE".

This moves one to the middle line of the screen, moves in 20 columns left, marks the beginning of the paste buffer, sets the left column, moves 5 columns down, sets the right column, and then marks the end of the paste buffer. Now try:

"C-a [ M 20 l SPACE 10 l 5 j SPACE"

and notice the difference in the amount of text copied.

J joins lines. It toggles between 4 modes: lines separated by a newline character (012), lines glued seamless, lines separated by a single whitespace and comma separated lines. Note that you can prepend the newline character with a carriage return character, by issuing a "crlf on".

v or V is for all the vi users with ":set numbers" - it toggles the left margin between column 9 and 1. Press

a before the final space key to toggle in append mode. Thus the contents of the paste buffer will not be overwritten, but is appended to.

A toggles in append mode and sets a (second) mark.

> sets the (second) mark and writes the contents of the paste buffer to the screen-exchange file (/tmp/screen-exchange per default) once copy-mode is finished.

This example demonstrates how to dump the whole scrollback buffer to that file: "C-A [ g SPACE G $ >".

C-g gives information about the current line and column.

x or o exchanges the first mark and the current cursor position. You can use this to adjust an already placed mark.

C-l ('el') will redraw the screen.

@ does nothing. Does not even exit copy mode.

All keys not described here exit copy mode.

copy_reg [key]

No longer exists, use "readreg" instead.

crlf [on|off]

This affects the copying of text regions with the `C-a [' command. If it is set to `on', lines will be separated by the two character sequence `CR' - `LF'. Otherwise (default) only `LF' is used. When no parameter is given, the state is toggled.

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.

defdynamictitle on|off

Set default behaviour for new windows regarding if screen should change window title when seeing proper escape sequence. See also "TITLES (naming windows)" section.

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.

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. ─────────────────────────────────────────────────────── j, C-n, or down Move down one line. ─────────────────────────────────────────────────────── C-a or home Move to the first line. ─────────────────────────────────────────────────────── C-e or end Move to the last line. ─────────────────────────────────────────────────────── C-u or C-d Move one half page up or down. ─────────────────────────────────────────────────────── C-b or C-f Move one full page up or down. ─────────────────────────────────────────────────────── mouseclick Move to the selected line. Available when "mousetrack" is set to on. ─────────────────────────────────────────────────────── space Refresh the list ─────────────────────────────────────────────────────── d Detach that display ─────────────────────────────────────────────────────── D Power detach that display ─────────────────────────────────────────────────────── C-g, enter, or escape Exit the list ───────────────────────────────────────────────────────

The following is an example of what "displays" could look like: xterm 80x42 jnweiger@/dev/ttyp4 0(m11) &rWx facit 80x24 mlschroe@/dev/ttyhf nb 11(tcsh) rwx xterm 80x42 jnhollma@/dev/ttyp5 0(m11) &R.x (A) (B) (C) (D) (E) (F)(G) (H)(I)

The legend is as follows:

(A) The terminal type known by screen for this display.

(B) Displays geometry as width x height.

(C) Username who is logged in at the display.

(D) Device name of the display or the attached device

(E) Display is in blocking or nonblocking mode. The available modes are "nb", "NB", "Z<", "Z>", and "BL".

(F) Number of the window

(G) Name/title of window

(H) Whether the window is shared

(I) Window permissions. Made up of three characters.

┌────────────────────────────────────────────────────────┐ │ Window permissions indicators │ ├─────────────────┬──────────────────┬───────────────────┤ │ 1st character │ 2nd character │ 3rd character │ ├────┬────────────┼─────┬────────────┼─────┬─────────────┤ │- │no read │ - │no write │ - │no execute │ ├────┼────────────┼─────┼────────────┼─────┼─────────────┤ │r │read │ w │write │ x │execute │ ├────┼────────────┼─────┼────────────┼─────┼─────────────┤ │ │ │ W │own wlock │ │ │ ├────┴────────────┴─────┴────────────┴─────┴─────────────┤ │Indicators of permissions suppressed by a foreign wlock │ ├────┬────────────┬─────┬────────────┬─────┬─────────────┤ │R │read only │ . │no write │ │ │ └────┴────────────┴─────┴────────────┴─────┴─────────────┘ "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.

dynamictitle on|off

Change behaviour for windows regarding if screen should change window title when seeing proper escape sequence. See also "TITLES (naming windows)" section.

echo [-n] message

The echo command may be used to annoy screen users with a 'message of the day'. Typically installed in a global /local/etc/screenrc. 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, KOI8-U, 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.

Invoking `exec' without arguments shows name and arguments of the currently running subprocess in this window. Only one subprocess a time can be running in each window.

When a subprocess is running the `kill' command will affect it instead of the windows process.

Refer to the postscript file `doc/fdpat.ps' for a confusing illustration of all 21 possible combinations. Each drawing shows the digits 2,1,0 representing the three file descriptors of newcommand. The box marked `W' is the usual pty that has the application-process on its slave side. The box marked `P' is the secondary pty that now has screen at its master side.

Abbreviations: Whitespace between the word `exec' and fdpat and the command can be omitted. Trailing dots and a fdpat consisting only of dots can be omitted. A simple `|' is synonymous for the pattern `!..|'; the word exec can be omitted here and can always be replaced by `!'.

Examples:

exec ... /bin/sh

exec /bin/sh

!/bin/sh

Creates another shell in the same window, while the original shell is still running. Output of both shells is displayed and user input is sent to the new /bin/sh.

exec !.. stty 19200

exec ! stty 19200

!!stty 19200

Set the speed of the window's tty. If your stty command operates on stdout, then add another `!'.

exec !..| less

|less

This adds a pager to the window output. The special character `|' is needed to give the user control over the pager although it gets its input from the window's process. This works, because less listens on stderr (a behavior that screen would not expect without the `|') when its stdin is not a tty. Less versions newer than 177 fail miserably here; good old pg still works.

!:sed -n s/.*Error.*/\007/p

Sends window output to both, the user and the sed command. The sed inserts an additional bell character (oct. 007) to the window output seen by screen. This will cause "Bell in window x" messages, whenever the string "Error" appears in the window.

fit

Change the window size to the size of the current region. This command is needed because screen doesn't adapt the window size automatically if the window is displayed more than once.

flow [on|off|auto]

Sets the flow-control mode for this window. Without parameters it cycles the current window's flow-control setting from "automatic" to "on" to "off". See the discussion on "FLOW- CONTROL" later on in this document for full details and note, that this is subject to change in future releases. Default is set by `defflow'.

focus [next|prev|up|down|left|right|top|bottom]

Move the input focus to the next region. This is done in a cyclic way so that the top left region is selected after the bottom right one. If no option is given it defaults to `next'. The next region to be selected is determined by how the regions are layered. Normally, the next region in the same layer would be selected. However, if that next region contains one or more layers, the first region in the highest layer is selected first. If you are at the last region of the current layer, `next' will move the focus to the next region in the lower layer (if there is a lower layer). `Prev' cycles in the opposite order. See "split" for more information about layers.

The rest of the options (`up', `down', `left', `right', `top', and `bottom') are more indifferent to layers. The option `up' will move the focus upward to the region that is touching the upper left corner of the current region. `Down' will move downward to the region that is touching the lower left corner of the current region. The option `left' will move the focus leftward to the region that is touching the upper left corner of the current region, while `right' will move rightward to the region that is touching the upper right corner of the current region. Moving left from a left most region or moving right from a right most region will result in no action.

The option `top' will move the focus to the very first region in the upper list corner of the screen, and `bottom' will move to the region in the bottom right corner of the screen. Moving up from a top most region or moving down from a bottom most region will result in no action.

Useful bindings are (h, j, k, and l as in vi) bind h focus left bind j focus down bind k focus up bind l focus right bind t focus top bind b focus bottom Note 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]

hardstatus [always]firstline|lastline|message|ignore[string]

hardstatus string[string]

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). When "firstline/lastline" is used, screen will reserve the first/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.

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;<string>^G" or "ESC_<string>ESC\") is displayed. You can customize this to any string you like including the escapes from the "STRING ESCAPES" chapter. 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.

height [-w|-d] [lines [cols]]

Set the display height to a specified number of lines. When no argument is given it toggles between 24 and 42 lines display. You can also specify a width if you want to change both values. The -w option tells screen to leave the display size unchanged and just set the window size, -d vice versa.

help[class]

Not really a online help, but displays a help screen showing you all the key bindings. The first pages list all the internal commands followed by their current bindings. Subsequent pages will display the custom commands, one command per key. Press space when you're done reading each page, or return to exit early. All other characters are ignored. If the "-c" option is given, display all bound commands for the specified command class. See also "DEFAULT KEY BINDINGS" section.

history

Usually users work with a shell that allows easy access to previous commands. For example csh has the command "!!" to repeat the last command executed. Screen allows you to have a primitive way of re-calling "the command that started ...": You just type the first letter of that command, then hit `C-a {' and screen tries to find a previous line that matches with the `prompt character' to the left of the cursor. This line is pasted into this window's input queue. Thus you have a crude command history (made up by the visible window and its scrollback buffer).

hstatus status

Change the window's hardstatus line to the string status.

idle [timeout[cmd-args]]

Sets a command that is run after the specified number of seconds inactivity is reached. This command will normally be the "blanker" command to create a screen blanker, but it can be any screen command. If no command is specified, only the timeout is set. A timeout of zero (or the special timeout off) disables the timer. If no arguments are given, the current settings are displayed.

ignorecase [on|off]

Tell screen to ignore the case of characters in searches. Default is `off'. Without any options, the state of ignorecase is toggled.

info

Uses the message line to display some information about the current window: the cursor position in the form "(column,row)" starting with "(1,1)", the terminal width and height plus the size of the scrollback buffer in lines, like in "(80,24)+50", the current state of window XON/XOFF flow control is shown like this (See also section FLOW CONTROL):

┌─────────┬──────────────────────────────────────────────────────────┐ │+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").

If the state machine of the terminal emulator is in a non-default state, the info line is started with a string identifying the current state.

For system information use the "time" command.

ins_reg [key]

No longer exists, use "paste" instead.

kill

Kill current window.

If there is an `exec' command running then it is killed. Otherwise the process (shell) running in the window receives a HANGUP condition, the window structure is removed and screen (your display) switches to another window. When the last window is destroyed, screen exits. After a kill screen switches to the previously displayed window.

Note: Emacs users should keep this command in mind, when killing a line. It is recommended not to use "C-a" as the screen escape key or to rebind kill to "C-a K".

lastmsg

Redisplay the last contents of the message/status line. Useful if you're typing when a message appears, because the message goes away when you press a key (unless your terminal has a hardware status line). Refer to the commands "msgwait" and "msgminwait" for fine tuning.

layout new [title]

Create a new layout. The screen will change to one whole region and be switched to the blank window. From here, you build the regions and the windows they show as you desire. The new layout will be numbered with the smallest available integer, starting with zero. You can optionally give a title to your new layout. Otherwise, it will have a default title of "layout". You can always change the title later by using the command layout title.

layout remove [n|title]

Remove, or in other words, delete the specified layout. Either the number or the title can be specified. Without either specification, screen will remove the current layout.

Removing a layout does not affect your set windows or regions.

layout next

Switch to the next layout available

layout prev

Switch to the previous layout available

layout select [n|title]

Select the desired layout. Either the number or the title can be specified. Without either specification, screen will prompt and ask which screen is desired. To see which layouts are available, use the layout show command.

layout show

List on the message line the number(s) and title(s) of the available layout(s). The current layout is flagged.

layout title [title]

Change or display the title of the current layout. A string given will be used to name the layout. Without any options, the current title and number is displayed on the message line.

layout number [n]

Change or display the number of the current layout. An integer given will be used to number the layout. Without any options, the current number and title is displayed on the message line.

layout attach [title|:last]

Change or display which layout to reattach back to. The default is :last, which tells screen to reattach back to the last used layout just before detachment. By supplying a title, You can instruct screen to reattach to a particular layout regardless which one was used at the time of detachment. Without any options, the layout to reattach to will be shown in the message line.

layout save [n|title]

Remember the current arrangement of regions. When used, screen will remember the arrangement of vertically and horizontally split regions. This arrangement is restored when a screen session is reattached or switched back from a different layout. If the session ends or the screen process dies, the layout arrangements are lost. The layout dump command should help in this siutation. If a number or title is supplied, screen will remember the arrangement of that particular layout. Without any options, screen will remember the current layout.

Saving your regions can be done automatically by using the layout autosave command.

layout autosave [on|off]

Change or display the status of automatcally saving layouts. The default is on, meaning when screen is detached or changed to a different layout, the arrangement of regions and windows will be remembered at the time of change and restored upon return. If autosave is set to off, that arrangement will only be restored to either to the last manual save, using layout save, or to when the layout was first created, to a single region with a single window. Without either an on or off, the current status is displayed on the message line.

layout dump [filename]

Write to a file the order of splits made in the current layout. This is useful to recreate the order of your regions used in your current layout. Only the current layout is recorded. While the order of the regions are recorded, the sizes of those regions and which windows correspond to which regions are not. If no filename is specified, the default is layout-dump, saved in the directory that the screen process was started in. If the file already exists, layout dump will append to that file. As an example:

C-a : layout dump /home/user/.screenrc

will 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.

Warning: When you leave other shells unlocked and you have no password set on screen, the lock is void: One could easily re- attach from an unlocked shell. This feature should rather be called `lockterminal'.

log [on|off]

Start/stop writing output of the current window to a file "screenlog.n" in the window's default directory, where n is the number of the current window. This filename can be changed with the `logfile' command. If no parameter is given, the state of logging is toggled. The session log is appended to the previous contents of the file if it already exists. The current contents and the contents of the scrollback history are not included in the session log. Default is `off'.

logfile filename

logfile flush secs

Defines the name the log files 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.

login [on|off]

Adds or removes the entry in the utmp database file for the current window. This controls if the window is `logged in'. When no parameter is given, the login state of the window is toggled. Additionally to that toggle, it is convenient having a `log in' and a `log out' key. E.g. `bind I login on' and `bind O login off' will map these keys to be C-a I and C-a O. The default setting (in config.h.in) should be "on" for a screen that runs under suid-root. Use the "deflogin" command to change the default login state for new windows. Both commands are only present when screen has been compiled with utmp support.

logtstamp [on|off]

logtstamp after [secs]

logtstamp string [string]

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).

mapdefault

Tell screen that the next input character should only be looked up in the default bindkey table. See also "bindkey".

mapnotnext

Like mapdefault, but don't even look in the default bindkey table.

maptimeout [timeout]

Set the inter-character timer for input sequence detection to a timeout of timeout ms. The default timeout is 300ms. Maptimeout with no arguments shows the current setting. See also "bindkey".

markkeys string

This is a method of changing the keymap used for copy/history mode. The string is made up of oldchar=newchar pairs which are separated by `:'. Example: The string "B=^B:F=^F" will change the keys `C-b' and `C-f' to the vi style binding (scroll up/down fill page). This happens to be the default binding for `B' and `F'. The command "markkeys h=^B:l=^F:$=^E" would set the mode for an emacs-style binding. If your terminal sends characters, that cause you to abort copy mode, then this command may help by binding these characters to do nothing. The no-op character is `@' and is used like this: "markkeys @=L=H" if you do not want to use the `H' or `L' commands any longer. As shown in this example, multiple keys can be assigned to one function in a single statement.

maxwin num

Set the maximum window number screen will create. Doesn't affect already existing windows. The number can be increased only when there are no existing windows.

meta

Insert the command character (C-a) in the current window's input stream.

monitor [on|off]

Toggles activity monitoring of windows. When monitoring is turned on and an affected window is switched into the background, you will receive the activity notification message in the status line at the first sign of output and the window will also be marked with an `@' in the window-status display. Monitoring is initially off for all windows.

mousetrack [on|off]

This command determines whether screen will watch for mouse clicks. When this command is enabled, regions that have been split in various ways can be selected by pointing to them with a mouse and left-clicking them. Without specifying on or off, the current state is displayed. The default state is determined by the "defmousetrack" command.

msgminwait sec

Defines the time screen delays a new message when one message is currently displayed. The default is 1 second.

msgwait sec

Defines the time a message is displayed if screen is not disturbed by other activity. The default is 5 seconds.

multiuser on|off

Switch between singleuser and multiuser mode. Standard screen operation is singleuser. In multiuser mode the commands `acladd', `aclchg', `aclgrp' and `acldel' can be used to enable (and disable) other users accessing this screen session.

nethack on|off

Changes the kind of error messages used by screen. When you are familiar with the game "nethack", you may enjoy the nethack-style messages which will often blur the facts a little, but are much funnier to read. Anyway, standard messages often tend to be unclear as well. This option is only available if screen was compiled with the NETHACK flag defined. The default setting is then determined by the presence of the environment variable $NETHACKOPTIONS and the file ~/.nethackrc - if either one is present, the default is on.

next

Switch to the next window. This command can be used repeatedly to cycle through the list of windows.

nonblock [on|off|numsecs]

Tell screen how to deal with user interfaces (displays) that cease to accept output. This can happen if a user presses ^S or a TCP/modem connection gets cut but no hangup is received. If nonblock is off (this is the default) screen waits until the display restarts to accept the output. If nonblock is on, screen waits until the timeout is reached (on is treated as 1s). If the display still doesn't receive characters, screen will consider it "blocked" and stop sending characters to it. If at some time it restarts to accept characters, screen will unblock the display and redisplay the updated window contents.

number [[+|-]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. Using `+' or `-' will change the window's number by the relative amount specified.

obuflimit [limit]

If the output buffer contains more bytes than the specified limit, no more data will be read from the windows. The default value is 256. If you have a fast display (like xterm), you can set it to some higher value. If no argument is specified, the current setting is displayed.

only

Kill all regions but the current one.

other

Switch to the window displayed previously. If this window does no longer exist, other has the same effect as next.

partial on|off

Defines whether the display should be refreshed (as with redisplay) after switching to the current window. This command only affects the current window. To immediately affect all windows use the allpartial command. Default is `off', of course. This default is fixed, as there is currently no defpartial command.

password [crypted_pw]

Present a crypted password in your ".screenrc" file and screen will ask for it, whenever someone attempts to resume a detached. This is useful if you have privileged programs running under screen and you want to protect your session from reattach attempts by another user masquerading as your uid (i.e. any superuser.) If no crypted password is specified, screen prompts twice for typing a password and places its encryption in the paste buffer. Default is `none', this disables password checking.

paste [registers [dest_reg]]

Write the (concatenated) contents of the specified registers to the stdin queue of the current window. The register '.' is treated as the paste buffer. If no parameter is given the user is prompted for a single register to paste. The paste buffer can be filled with the copy, history and readbuf commands. Other registers can be filled with the register, readreg and paste commands. If paste is called with a second argument, the contents of the specified registers is pasted into the named destination register rather than the window. If '.' is used as the second argument, the displays paste buffer is the destination. Note, that "paste" uses a wide variety of resources: Whenever a second argument is specified no current window is needed. When the source specification only contains registers (not the paste buffer) then there need not be a current display (terminal attached), as the registers are a global resource. The paste buffer exists once for every user.

pastefont [on|off]

Tell screen to include font information in the paste buffer. The default is not to do so. This command is especially useful for multi character fonts like kanji.

pow_break

Reopen the window's terminal line and send a break condition. See `break'.

pow_detach

Power detach. Mainly the same as detach, but also sends a HANGUP signal to the parent process of screen. CAUTION: This will result in a logout, when screen was started from your login- shell.

pow_detach_msg [message]

The message specified here is output whenever a `Power detach' was performed. It may be used as a replacement for a logout message or to reset baud rate, etc. Without parameter, the current message is shown.

prev

Switch to the window with the next lower number. This command can be used repeatedly to cycle through the list of windows.

printcmd [cmd]

If cmd is not an empty string, screen will not use the terminal capabilities "po/pf" if it detects an ansi print sequence ESC [ 5 i, but pipe the output into cmd. This should normally be a command like "lpr" or "'cat > /tmp/scrprint'". printcmd without a command displays the current setting. The ansi sequence ESC \ ends printing and closes the pipe.

Warning: Be careful with this command! If other user have write access to your terminal, they will be able to fire off print commands.

process [key]

Stuff the contents of the specified register into screen's input queue. If no argument is given you are prompted for a register name. The text is parsed as if it had been typed in from the user's keyboard. This command can be used to bind multiple actions to a single key.

quit

Kill all windows and terminate screen. Note that on VT100-style terminals the keys C-4 and C-\ are identical. This makes the default bindings dangerous: Be careful not to type C-a C-4 when selecting window no. 4. Use the empty bind command (as in "bind '^\'") to remove a key binding.

readbuf [encoding] [filename]

Reads the contents of the specified file into the paste buffer. You can tell screen the encoding of the file via the -e option. If no file is specified, the screen-exchange filename is used. See also "bufferfile" command.

readreg [encoding] [register [filename]]

Does one of two things, dependent on number of arguments: with zero or one arguments it duplicates the paste buffer contents into the register specified or entered at the prompt. With two arguments it reads the contents of the named file into the register, just as readbuf reads the screen-exchange file into the paste buffer. You can tell screen the encoding of the file via the -e option. The following example will paste the system's password file into the screen window (using register p, where a copy remains):

C-a : readreg p /etc/passwd C-a : paste p

redisplay

Redisplay the current window. Needed to get a full redisplay when in partial redraw mode.

register [-eencoding]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 [-h|-v|-b|-l|-p] [[+|-] n[%] |=|max|min|_|0]

Resize the current region. The space will be removed from or added to the surrounding regions depending on the order of the splits. The available options for resizing are `-h'(horizontal), `-v'(vertical), `-b'(both), `-l'(local to layer), and `-p'(perpendicular). Horizontal resizes will add or remove width to a region, vertical will add or remove height, and both will add or remove size from both dimensions. Local and perpendicular are similar to horizontal and vertical, but they take in account of how a region was split. If a region's last split was horizontal, a local resize will work like a vertical resize. If a region's last split was vertical, a local resize will work like a horizontal resize. Perpendicular resizes work in opposite of local resizes. If no option is specified, local is the default.

The amount of lines to add or remove can be expressed a couple of different ways. By specifying a number n by itself will resize the region by that absolute amount. You can specify a relative amount by prefixing a plus `+' or minus `-' to the amount, such as adding +n lines or removing -n lines. Resizing can also be expressed as an absolute or relative percentage by postfixing a percent sign `%'. Using zero `0' is a synonym for `min' and using an underscore `_' is a synonym for `max'.

Some examples are:

resize +N increase current region by N

resize -N decrease current region by N

resize N set current region to N

resize 20% set current region to 20% of original size

resize +20% increase current region by 20%

resize -b = make all windows equally

resize max maximize current region

resize min minimize current region

Without any arguments, screen will prompt for how you would like to resize the current region.

See "focusminsize" if you want to restrict the minimun size a region can have.

screen [-opts] [n] [cmd [args]|//group]

Establish a new window. The flow-control options (-f, -fn and -fa), title (a.k.a.) option (-t), login options (-l and -ln) , terminal type option (-T <term>), the all-capability-flag (-a) and scrollback option (-h <num>) may be specified with each command. The option (-M) turns monitoring on for this window. The option (-L) turns output logging on for this window. If an optional number n in the range 0..MAXWIN-1 is given, the window number n is assigned to the newly created window (or, if this number is already in-use, the next available number). If a command is specified after "screen", this command (with the given arguments) is started in the window; otherwise, a shell is created. If //group is supplied, a container-type window is created in which other windows may be created inside it.

Thus, if your ".screenrc" contains the lines

# example for .screenrc: screen 1 screen -fn -t foobar -L 2 telnet foobar

screen creates a shell window (in window #1) and a window with a TELNET connection to the machine foobar (with no flow-control using the title "foobar" in window #2) 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.

Screen has built in some functionality of "cu" and "telnet". See also chapter "WINDOW TYPES".

scrollback num

Set the size of the scrollback buffer for the current windows to num lines. The default scrollback is 100 lines. See also the "defscrollback" command and use "info" to view the current setting. To access and use the contents in the scrollback buffer, use the "copy" command.

select [WindowID]

Switch to the window identified by WindowID. This can be a prefix of a window title (alphanumeric window name) or a window number. The parameter is optional and if omitted, you get prompted for an identifier. When a new window is established, the first available number is assigned to this window. Thus, the first window can be activated by "select 0". The number of windows is limited at compile-time by the MAXWIN configuration parameter (which defaults to 40). There are two special WindowIDs, "-" selects the internal blank window and "." selects the current window. The latter is useful if used with screen's "-X" option.

sessionname [name]

Rename the current session. Note, that for "screen -list" the name shows up with the process-id prepended. If the argument "name" is omitted, the name of this session is displayed. Caution: The $STY environment variables will still reflect the old name in pre-existing shells. This may result in confusion. Use of this command is generally discouraged. Use the "-S" command-line option if you want to name a new session. The default is constructed from the tty and host names.

setenv [var [string]]

Set the environment variable var to value string. If only var is specified, the user will be prompted to enter a value. If no parameters are specified, the user will be prompted for both variable and value. The environment is inherited by all subsequently forked shells.

setsid [on|off]

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.

shell command

Set the command to be used to create a new shell. This overrides the value of the environment variable $SHELL. This is useful if you'd like to run a tty-enhancer which is expecting to execute the program specified in $SHELL. If the command begins with a '-' character, the shell will be started as a login-shell. Typical shells do only minimal initialization when not started as a login-shell. E.g. Bash will not read your "~/.bashrc" unless it is a login-shell.

shelltitle title

Set the title for all shells created during startup or by the C-A C-c command. For details about what a title is, see the discussion entitled "TITLES (naming windows)".

silence [on|off|sec]

Toggles silence monitoring of windows. When silence is turned on and an affected window is switched into the background, you will receive the silence notification 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.

silencewait sec

Define the time that all windows monitored for silence should wait before displaying a message. Default 30 seconds.

sleep num

This command will pause the execution of a .screenrc file for num seconds. Keyboard activity will end the sleep. It may be used to give users a chance to read the messages output by "echo".

slowpaste msec

Define the speed at which text is inserted into the current window by the paste ("C-a ]") command. If the slowpaste value is nonzero text is written character by character. screen will make a pause of msec milliseconds after each single character write to allow the application to process its input. Only use slowpaste if your underlying system exposes flow control problems while pasting large amounts of text.

sort

Sort the windows in alphabetical order of the window tiles.

source file

Read and execute commands from file file. Source commands may be nested to a maximum recursion level of ten. If file is not an absolute path and screen is already processing a source command, the parent directory of the running source command file is used to search for the new command file before screen's current directory.

Note that termcap/terminfo/termcapinfo commands only work at startup and reattach time, so they must be reached via the default screenrc files to have an effect.

sorendition [attr[color]]

This command is deprecated. See "rendition so" instead.

split[-v]

Split the current region into two new ones. All regions on the display are resized to make room for the new region. The blank window is displayed in the new region. The default is to create a horizontal split, putting the new regions on the top and bottom of each other. Using `-v' will create a vertical split, causing the new regions to appear side by side of each other. Use the "remove" or the "only" command to delete regions. Use "focus" to toggle between regions.

When a region is split opposite of how it was previously split (that is, vertical then horizontal or horizontal then vertical), a new layer is created. The layer is used to group together the regions that are split the same. Normally, as a user, you should not see nor have to worry about layers, but they will affect how some commands ("focus" and "resize") behave.

With this current implementation of screen, scrolling data will appear much slower in a vertically split region than one that is not. This should be taken into consideration if you need to use system commands such as "cat" or "tail -f".

startup_message on|off

Select whether you want to see the copyright notice during startup. Default is `on', as you probably noticed.

status [top|up|down|bottom] [left|right]

The status window by default is in bottom-left corner. This command can move status messages to any corner of the screen. top is the same as up, down is the same as bottom.

stuff [string]

Stuff the string string in the input buffer of the current window. This is like the "paste" command but with much less overhead. Without a parameter, screen will prompt for a string to stuff. You cannot paste large buffers with the "stuff" command. It is most useful for key bindings. See also "bindkey".

su [username [password [password2]]]

Substitute the user of a display. The command prompts for all parameters that are omitted. If passwords are specified as parameters, they have to be specified un-crypted. The first password is matched against the systems passwd database, the second password is matched against the screen password as set with the commands "acladd" or "password". "Su" may be useful for the screen administrator to test multiuser setups. When the identification fails, the user has access to the commands available for user nobody. These are "detach", "license", "version", "help" and "displays".

suspend

Suspend screen. The windows are in the `detached' state, while screen is suspended. This feature relies on the shell being able to do job control.

term term

In each window's environment screen opens, the $TERM variable is set to "screen" by default. But when no description for "screen" is installed in the local termcap or terminfo data base, you set $TERM to - say - "vt100". This won't do much harm, as screen is VT100/ANSI compatible. The use of the "term" command is discouraged for non-default purpose. That is, one may want to specify special $TERM settings (e.g. vt100) for the next "screen rlogin othermachine" command. Use the command "screen -T vt100 rlogin othermachine" rather than setting and resetting the default.

termcap term terminal-tweaks[window-tweaks]

terminfo term terminal-tweaks[window-tweaks]

termcapinfo term terminal-tweaks[window-tweaks]

Use this command to modify your terminal's termcap entry without going through all the hassles involved in creating a custom termcap entry. Plus, you can optionally customize the termcap generated for the windows. You have to place these commands in one of the screenrc startup files, as they are meaningless once the terminal emulator is booted.

If your system uses the terminfo database rather than termcap, screen will understand the `terminfo' command, which has the same effects as the `termcap' command. Two separate commands are provided, as there are subtle syntactic differences, e.g. when parameter interpolation (using `%') is required. Note that termcap names of the capabilities have to be used with the `terminfo' command.

In many cases, where the arguments are valid in both terminfo and termcap syntax, you can use the command `termcapinfo', which is just a shorthand for a pair of `termcap' and `terminfo' commands with identical arguments.

The first argument specifies which terminal(s) should be affected by this definition. You can specify multiple terminal names by separating them with `|'s. Use `*' to match all terminals and `vt*' to match all terminals that begin with "vt".

Each tweak argument contains one or more termcap defines (separated by `:'s) to be inserted at the start of the appropriate termcap entry, enhancing it or overriding existing values. The first tweak modifies your terminal's termcap, and contains definitions that your terminal uses to perform certain functions. Specify a null string to leave this unchanged (e.g. ''). The second (optional) tweak modifies all the window termcaps, and should contain definitions that screen understands (see the "VIRTUAL TERMINAL" section).

Some examples:

termcap xterm* LP:hs@

Informs screen that all terminals that begin with `xterm' have firm auto-margins that allow the last position on the screen to be updated (LP), but they don't really have a status line (no 'hs' - append `@' to turn entries off). Note that we assume `LP' for all terminal names that start with "vt", but only if you don't specify a termcap command for that terminal. termcap vt* LP

termcap vt102|vt220 Z0=\E[?3h:Z1=\E[?3l

Specifies the firm-margined `LP' capability for all terminals that begin with `vt', and the second line will also add the escape-sequences to switch into (Z0) and back out of (Z1) 132-character-per-line mode if this is a VT102 or VT220. (You must specify Z0 and Z1 in your termcap to use the width-changing commands.)

termcap vt100 "" l0=PF1:l1=PF2:l2=PF3:l3=PF4

This leaves your vt100 termcap alone and adds the function key labels to each window's termcap entry.

termcap h19|z19 am@:im=\E@:ei=\EO dc=\E[P

Takes a h19 or z19 termcap and turns off auto-margins (am@) and enables the insert mode (im) and end-insert (ei) capabilities (the `@' in the `im' string is after the `=', so it is part of the string). Having the `im' and `ei' definitions put into your terminal's termcap will cause screen to automatically advertise the character-insert capability in each window's termcap. Each window will also get the delete-character capability (dc) added to its termcap, which screen will translate into a line-update for the terminal (we're pretending it doesn't support character deletion).

If you would like to fully specify each window's termcap entry, you should instead set the $SCREENCAP variable prior to running screen. See the discussion on the "VIRTUAL TERMINAL" in this manual, and the termcap(5) man page for more information on termcap definitions.

title [windowtitle]

Set the name of the current window to windowtitle. If no name is specified, screen prompts for one. This command was known as `aka' in previous releases.

truecolor [on|off]

Enables truecolor support. Currently autodetection of truecolor support cannot be done reliably, as such it's left to user to enable. Default is off. Known terminals that may support it are: iTerm2, Konsole, st. Xterm includes support for truecolor escapes but converts them back to indexed 256 color space.

unbindall

Unbind all the bindings. This can be useful when screen is used solely for its detaching abilities, such as when letting a console application run as a daemon. If, for some reason, it is necessary to bind commands after this, use 'screen -X'.

unsetenv var

Unset an environment variable.

utf8 [on|off[on|off]]

Change the encoding used in the current window. If utf8 is enabled, the strings sent to the window will be UTF-8 encoded and vice versa. Omitting the parameter toggles the setting. If a second parameter is given, the display's encoding is also changed (this should rather be done with screen's "-U" option). See also "defutf8", which changes the default setting of a new window.

vbell [on|off]

Sets the visual bell setting for this window. Omitting the parameter toggles the setting. If vbell is switched on, but your terminal does not support a visual bell, a `vbell-message' is displayed in the status line when the bell character (^G) is received. Visual bell support of a terminal is defined by the termcap variable `vb' (terminfo: 'flash').

Per default, vbell is off, thus the audible bell is used. See also `bell_msg'.

vbell_msg [message]

Sets the visual bell message. message is printed to the status line if the window receives a bell character (^G), vbell is set to "on", but the terminal does not support a visual bell. The default message is "Wuff, Wuff!!". Without a parameter, the current message is shown.

vbellwait sec

Define a delay in seconds after each display of screen's visual bell message. The default is 1 second.

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 a parameter, the current setting is shown.

version

Print the current version and the compile date in the status line.

wall message

Write a message to all displays. The message will appear in the terminal's status line.

width [-w|-d] [cols [lines]]

Toggle the window width between 80 and 132 columns or set it to cols columns if an argument is specified. This requires a capable terminal and the termcap entries "Z0" and "Z1". See the "termcap" command for more information. You can also specify a new height if you want to change both values. The -w option tells screen to leave the display size unchanged and just set the window size, -d vice versa.

windowlist [-b] [-m] [-g]

windowlist string [string]

windowlist title [title]

Display all windows in a table for visual window selection. If screen was in a window group, screen will back out of the group and then display the windows in that group. If the -b option is given, screen will switch to the blank window before presenting the list, so that the current window is also selectable. The -m option changes the order of the windows, instead of sorting by window numbers screen uses its internal most-recently-used list. The -g option will show the windows inside any groups in that level and downwards.

The following keys are used to navigate in "windowlist":

───────────────────────────────────────────────────────────────────── k, C-p, or up Move up one line. ───────────────────────────────────────────────────────────────────── j, C-n, or down Move down one line. ───────────────────────────────────────────────────────────────────── C-g or escape Exit windowlist. ───────────────────────────────────────────────────────────────────── C-a or home Move to the first line. ───────────────────────────────────────────────────────────────────── C-e or end Move to the last line. ───────────────────────────────────────────────────────────────────── C-u or C-d Move one half page up or down. ───────────────────────────────────────────────────────────────────── C-b or C-f Move one full page up or down. ───────────────────────────────────────────────────────────────────── 0..9 Using the number keys, move to the selected line. ───────────────────────────────────────────────────────────────────── mouseclick Move to the selected line. Available when "mousetrack" is set to "on" ───────────────────────────────────────────────────────────────────── / Search. ───────────────────────────────────────────────────────────────────── n Repeat search in the forward direction. ───────────────────────────────────────────────────────────────────── N Repeat search in the backward direction. ───────────────────────────────────────────────────────────────────── m Toggle MRU. ───────────────────────────────────────────────────────────────────── g Toggle group nesting. ───────────────────────────────────────────────────────────────────── a All window view. ─────────────────────────────────────────────────────────────────────

C-h or backspace Back out the group. ───────────────────────────────────────────────────────────────────── , Switch numbers with the previous window. ───────────────────────────────────────────────────────────────────── . Switch numbers with the next window. ───────────────────────────────────────────────────────────────────── K Kill that window. ───────────────────────────────────────────────────────────────────── space or enter Select that window. ─────────────────────────────────────────────────────────────────────

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 [ string ]

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. The optional string parameter follows the "STRING ESCAPES" format. If string parameter is passed, the output size is unlimited. The default command without any parameter is limited to a size of 1024 bytes.

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

xon

Insert a CTRL-s / CTRL-q character to the stdin queue of the current window.

zmodem [off|auto|catch|pass]

zmodem sendcmd [string]

zmodem recvcmd [string]

Define zmodem support for screen. Screen understands two different modes when it detects a zmodem request: "pass" and "catch". If the mode is set to "pass", screen will relay all data to the attacher until the end of the transmission is reached. In "catch" mode screen acts as a zmodem endpoint and starts the corresponding rz/sz commands. If the mode is set to "auto", screen will use "catch" if the window is a tty (e.g. a serial line), otherwise it will use "pass".

You can define the templates screen uses in "catch" mode via the second and the third form.

Note also that this is an experimental feature.

zombie [keys[onerror]]

Per default screen windows are removed from the window list as soon as the windows process (e.g. shell) exits. When a string of two keys is specified to the zombie command, `dead' windows will remain in the list. The kill command may be used to remove such a window. Pressing the first key in the dead window has the same effect. When pressing the second key, screen will attempt to resurrect the window. The process that was initially running in the window will be launched again. Calling zombie without parameters will clear the zombie setting, thus making windows disappear when their process exits.

As the zombie-setting is manipulated globally for all windows, this command should probably be called defzombie, but it isn't.

Optionally you can put the word "onerror" after the keys. This will cause screen to monitor exit status of the process running in the window. If it exits normally ('0'), the window disappears. Any other exit value causes the window to become a zombie.

zombie_timeout[seconds]

Per default screen windows are removed from the window list as soon as the windows process (e.g. shell) exits. If zombie keys are defined (compare with above zombie command), it is possible to also set a timeout when screen tries to automatically reconnect a dead screen window.