диспетчер экрана с эмуляцией терминала VT100 / ANSI (screen manager with VT100/ANSI terminal emulation)
FLOW-CONTROL
Each window has a flow-control setting that determines how screen
deals with the XON and XOFF characters (and perhaps the interrupt
character). When flow-control is turned off, screen ignores the
XON and XOFF characters, which allows the user to send them to
the current program by simply typing them (useful for the emacs
editor, for instance). The trade-off is that it will take longer
for output from a "normal" program to pause in response to an
XOFF. With flow-control turned on, XON and XOFF characters are
used to immediately pause the output of the current window. You
can still send these characters to the current program, but you
must use the appropriate two-character screen commands (typically
"C-a q" (xon) and "C-a s" (xoff)). The xon/xoff commands are
also useful for typing C-s and C-q past a terminal that
intercepts these characters.
Each window has an initial flow-control value set with either the
-f option or the "defflow" .screenrc command. Per default the
windows are set to automatic flow-switching. It can then be
toggled between the three states 'fixed on', 'fixed off' and
'automatic' interactively with the "flow" command bound to "C-a
f".
The automatic flow-switching mode deals with flow control using
the TIOCPKT mode (like "rlogin" does). If the tty driver does not
support TIOCPKT, screen tries to find out the right mode based on
the current setting of the application keypad - when it is
enabled, flow-control is turned off and visa versa. Of course,
you can still manipulate flow-control manually when needed.
If you're running with flow-control enabled and find that
pressing the interrupt key (usually C-c) does not interrupt the
display until another 6-8 lines have scrolled by, try running
screen with the "interrupt" option (add the "interrupt" flag to
the "flow" command in your .screenrc, or use the -i command-line
option). This causes the output that screen has accumulated from
the interrupted program to be flushed. One disadvantage is that
the virtual terminal's memory contains the non-flushed version of
the output, which in rare cases can cause minor inaccuracies in
the output. For example, if you switch screens and return, or
update the screen with "C-a l" you would see the version of the
output you would have gotten without "interrupt" being on. Also,
you might need to turn off flow-control (or use auto-flow mode to
turn it off automatically) when running a program that expects
you to type the interrupt character as input, as it is possible
to interrupt the output of the virtual terminal to your physical
terminal when flow-control is enabled. If this happens, a simple
refresh of the screen with "C-a l" will restore it. Give each
mode a try, and use whichever mode you find more comfortable.
