screen: Overview
1 Overview
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Screen is a full-screen window manager that multiplexes a physical
terminal between several processes, typically interactive shells. Each
virtual terminal provides the functions of the DEC VT100 terminal and,
in addition, several control functions from the ISO 6429 (ECMA 48, ANSI
X3.64) and ISO 2022 standards (e.g. insert/delete line and support for
multiple character sets). There is a scrollback history buffer for each
virtual terminal and a copy-and-paste mechanism that allows the user to
move text regions between windows.
When 'screen' is called, it creates a single window with a shell in
it (or the specified command) and then gets out of your way so that you
can use the program as you normally would. Then, at any time, you can
create new (full-screen) windows with other programs in them (including
more shells), kill the current window, view a list of the active
windows, turn output logging on and off, copy text between windows, view
the scrollback history, switch between windows, etc. All windows run
their programs completely independent of each other. Programs continue
to run when their window is currently not visible and even when the
whole screen session is detached from the user's terminal.
When a program terminates, 'screen' (per default) kills the window
that contained it. If this window was in the foreground, the display
switches to the previously displayed window; if none are left, 'screen'
exits. Shells usually distinguish between running as login-shell or
sub-shell. Screen runs them as sub-shells, unless told otherwise (See
'shell' .screenrc command).
Everything you type is sent to the program running in the current
window. The only exception to this is the one keystroke that is used to
initiate a command to the window manager. By default, each command
begins with a control-a (abbreviated 'C-a' from now on), and is followed
Character::) and all the key bindings (
Key Binding) can be fully
customized to be anything you like, though they are always two
characters in length.
'Screen' does not understand the prefix 'C-' to mean control,
although this notation is used in this manual for readability. Please
use the caret notation ('^A' instead of 'C-a') as arguments to e.g. the
'escape' command or the '-e' option. 'Screen' will also print out
control characters in caret notation.
The standard way to create a new window is to type 'C-a c'. This
creates a new window running a shell and switches to that window
immediately, regardless of the state of the process running in the
current window. Similarly, you can create a new window with a custom
command in it by first binding the command to a keystroke (in your
'.screenrc' file or at the 'C-a :' command line) and then using it just
like the 'C-a c' command. In addition, new windows can be created by
running a command like:
screen emacs prog.c
from a shell prompt within a previously created window. This will not
run another copy of 'screen', but will instead supply the command name
and its arguments to the window manager (specified in the $STY
environment variable) who will use it to create the new window. The
above example would start the 'emacs' editor (editing 'prog.c') and
switch to its window. - Note that you cannot transport environment
variables from the invoking shell to the application (emacs in this
case), because it is forked from the parent screen process, not from the
invoking shell.
If '/etc/utmp' is writable by 'screen', an appropriate record will be
written to this file for each window, and removed when the window is
closed. This is useful for working with 'talk', 'script', 'shutdown',
'rsend', 'sccs' and other similar programs that use the utmp file to
determine who you are. As long as 'screen' is active on your terminal,
the terminal's own record is removed from the utmp file. Login.
Info Catalog
screen: Top
screen: Top
screen: Getting Started