GNU screen

screen is flexible about flow control. Traditionally, some terminals do flow control in-band, using ^S when they want to stop the flow data and ^Q when they want it to resume. On the other hand, some programs (such as emacs) use those keys for other purposes. If flow control is turned on in screen, ^S will stop screen from sending anything more to your terminal and ^Q will resume. Turning flow control off allows those characters to pass through to your programs. The default setting is “auto”, which attempts to determine if flow control is needed or not. screen is generally pretty good at figuring this out.

screen can deal with multiple character sets and character encodings. The encoding and defencoding commands can be used to set window encodings or override the detected terminal encoding. If the display's and window's encodings differ, screen will translate btween the two. Characters not in the display's charset are represented by question marks. screen does its own encoding and only supports a handful of encodings. As of version 4.0.2, those are: C, eucJP, SJIS, eucKR, eucCN, Big5, KOI8-R, CP1251, UTF-8, ISO8859-2, ISO8859-3, ISO8859-4, ISO8859-5, ISO8859-6, ISO8859-7, ISO8859-8, ISO8859-9, ISO8859-10, ISO8859-15, jis, and GBK. off'' - Global command equivalent to setting ''partial'' for all current windows. Default is off. * ''altscreen on|off'' - Enables "alternate screen" support (''ti'' and ''te'' termcap settings) for screen windows. Does not change existing windows. Default is off. * ''bce [on|off]'' - Set or toggle 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." Most noticeable when your terminal's "default" background is different from the current background color, such as an xterm with a background image. [//What's the default setting? <PMG>//] * ''c1 [on|off]'' - Sets or toggles c1 code processing. If on, characters with the high bit set will be treated as an ESC followed by the corresponding 7-bit character. Default is off. * ''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 an ''encoding'' command is active." [//I don't really understand this. It's obviously terminal charset munging, but I don't get the particulars--I just use UTF-8. <PMG>//] * ''defbce on|off'' - Same as ''bce'', but sets the default setting for new windows. * ''defbreaktype [tcsendbreak|TIOCSBRK|TCSBRK]'' - Sets the type of break signal sent via the ''break'' or ''pow_break'' command. Recommended settings are tcsendbreak and TIOCSBRK. TCSBRK blocks the whole session, but may be the only way to get long breaks. [//The man page is somewhat light on detail here. Clarifications appreciated. <PMG>//] * ''defc1 on|off'' - Same as ''c1'', but sets the default setting for new windows. * ''defcharset [//set//]'' - Same as ''charset'', but sets the default setting for new windows. * ''defflow on|off|auto [interrupt]'' - Same as ''flow'', but sets the default setting for new windows. * ''defgr on|off'' - Same as ''gr'', but sets the default setting for new windows. * ''defencoding //enc//'' - Same as ''encoding'', but sets the default setting for new windows. * ''defnonblock on|off|//numsecs//'' - Same as ''nonblock''. but sets the default setting for new displays. * ''defutf8 on|off'' - Same as ''utf8'', but sets the default setting for new windows. * ''defwrap on|off'' - Same as ''wrap'', but sets the default setting for new windows. * ''dinfo'' - Shows wha settings screen is using for the current display. As of screen 4.0.2 shows: display dimensions (columns, rows), encoding, whether the display is an xterm, whether the display supports color, and what charset is in use (one of iso2022 or altchar). * ''dumptermcap'' - Tells screen to create a .termcap file in its socket directory. The file will contain all the termcap settings for screen's virtual terminal. It's the same as the $TERMCAP environment variable that screen sets, but can be used for programs that don't understand $TERMCAP. * ''encoding //enc// [//enc//]'' - Set the character encoding for the current window. The second argument sets the character encoding for the current display (and is rarely needed because screen can usually tell from its locale settings). * ''flow [on|off|auto]'' - Sets the current window's flow control mode. * ''gr [on|off]'' - Sets or toggles GR charset switching. If on, when asked to display a character with the 8th bit set, screen uses the GR charset. While necessary for some terminals, it is not compatible with 8-bit encodings (such as ISO8859-1) and dfaults to off. * ''nonblock [on|off|//numsecs//]'' - Sets or toggles screen's behavior when a display stops receiving characters. When off, screen blocks on sending to the terminal; in some situations this can freeze the entire session. When on, screen waits the specified timeout (''on'' is equivalent to 1 second); if the display still does not respond, screen stops sending to it until it recovers. Default is off. * ''partial on|off'' - Sets whether screen should draw the entire window when switching windows. If on, screen will blank the display and then draw only the line that the cursor is on. Useful for slow terminals. Default is off. * ''printcmd [//cmd//]'' - Shows or sets the command used for handling the ANSI print sequence ''ESC [ 5 i''. If set, the text to be printed will be given to the command on standard input. If unset, screen will use the ''po'' and ''pf'' terminal capabilities to tell the display terminal to print the text. Default is unset. * ''reset'' - Resets the current window's virtual terminal settings to their default settings. Only affects changes made by escape sequences (things like scrolling regions, color settings, etc.), not changes made by screen commands. Effectively the same as power-cycling a physical terminal. * ''term //term//'' - Changes the value of $TERM that screen passes to its windows' child processes. Useful when the default, 'screen', is unknown to a system. Be careful to set it to a compatible value; 'vt100' is recommended. * ''[termcap|terminfo|termcapinfo] //term// //terminal-tweaks// [//window-tweaks//]'' - Tweaks termcap entries for either screen's interaction with the display terminal (//terminal-tweaks//) or for the virtual terminal presented to child programs (//window-tweaks//). See "Extras" section for discussion. * ''utf8 [on|off [on|off - Changes or toggles the encoding on the current window. The second parameter changes the UTF-8 setting of the display. (The -U option is the preferred way to set that, however.) [Is this merely equivalent to encoding UTF-8? <PMG>] * wrap [on|off] - Sets or toggles the current window's line wrap setting. When on, characters displayed while the cursor is at the end of the line will cause the cursor to wrap to the next line. When off, the cursor will stay at the end of the line, and the characters will overwrite each other. Default is on. * zmodem [off|auto|catch|pass] - Sets screen's handling of zmodem communcations. pass means that screen will not do anything to zmodem streams and will relay them to the display terminal. catch means that screen will catch and intermret the streams itself; the display terminal will not see them. auto attempts to determine what the correct setting is; it uses catch if the display is a tty and pass if the display is a pseudoterminal. [But what does off mean? <PMG>] This is an experimental feature. * zmodem sendcmd|recvcmd [string] - Sets the templates used when in catch'' mode for the zmodem protocol.