.TH sympathy 1 "%VERSIONSTAMP%" "%LONGVERSION%" "USER COMMANDS"
+.\" $Id: sympathy.1,v 1.28 2008/05/09 12:31:55 james Exp $
.SH NAME
sympathy \- client/server terminal emulator with logging
.SH SYNOPSIS
.B \fIserver_options\fP
] [
.B \fIclient_options\fP
+] [
+.B \fIdisplay_options\fP
]
.br
.B sympathy \-\fBc\fP
[
.B \fIclient_options\fP
+] [
+.B \fIdisplay_options\fP
]
.br
.B sympathy \-\fBr\fP
id
[
.B \fIclient_options\fP
+] [
+.B \fIdisplay_options\fP
]
.br
+.B sympathy \-\fBC\fP \-\fBd\fP
+serialdev
+.br
+.B sympathy \-\fBls\fP
+.br
.B sympathy \-\fBv\fP
.br
-.\" "sympathy -t [-K] [-d serialdev|-p] [-b baud] [-f] [-L log] [-u]\n"
-.\" "sympathy -s [-K] [-d serialdev|-p] [-b baud] [-f] [-L log] [-u] [-k skt]\n"
-.\" " [-n hlines] [-w WxH] [-F]\n"
-.\" "sympathy [-s -c] [-K] [-d serialdev|-p] [-b baud] [-f] [-L log] [-u] [-k skt]\n"
-.\" " [-n hlines] [-w WxH]\n"
-.\" "sympathy -c [-H] [-u] -k skt\n"
-.\" "sympathy -r id [-H] [-u]\n"
-.\" "sympathy {-l|-ls}\n"
-.\" "sympathy -v\n"
-.\" "sympathy -h\n"
-
.SH DESCRIPTION
.I Sympathy
+is a replacement for screen(1), minicom(1) and consolidate(1). It
is a VT52/VT100/ANSI terminal emulator with some special features. In normal use
.I sympathy
-would sit between a terminal device (a serial port or a ptty) and
-the user's usual terminal emaulator (eg xterm(1)).
+would sit between a terminal device (a serial port or a pseudo-tty) and
+the user's usual terminal emulator (eg xterm(1)).
.I Sympathy
renders data from the terminal device into an internal frame buffer
and then expresses changes in this frame buffer to the outer terminal
.I Sympathy
always generates valid escape codes to the outer terminal, and will
reset the state of its internal terminal emulator when it detects
-framing errors on the terminal device.
+receive errors on the terminal device.
.PP
.I Sympathy\fP,
-unlike screen(1), takes care to preserve the scrollback features
-of the outer terminal emulator: lines that scroll of the top of the internal
-frame buffer are scrolled off the top of the outer terminal emaultor. When
-sympathy is used in client/server mode, some history is added to the outer
+unlike screen(1), takes care to preserve the scroll-back features
+of the outer terminal emulator: lines that scroll off the top of the internal
+frame buffer are scrolled off the top of the outer terminal emulator. When
+.I sympathy
+is used in client/server mode, some history is added to the outer
terminal emulator when the client connects.
.PP
.I Sympathy
-also supports automatic baud rate detection, and advanced logging features.
+also supports automatic baud\-rate detection, and advanced logging features.
.I Sympathy
logs whenever any of the modem control lines change state, receive errors,
and the contents
.SH OPTIONS
.B \fImajor mode options\fP:
.TP 5
-.B \-t
-act as terminal emulator only:
-.I sympathy
-opens the terminal device and outputs into the outer terminal emulator, when sympathy exits the
-device is closed and no process remains. In this mode sympathy behaves like a traditional
-terminal emulator such as cu(1) or minicom(1).
-.TP 5
-.B \-s
-act as server only:
-.I sympathy
-opens the terminal device and renders into an internal frame buffer, listens for clients
-on the socket and logs activity. By default the server will fork into a daemon processes
-but can be forced to remain in the forground with the \-\fBF\fP option.
+.B \-C\fP
+clear lock files
+.I sympathy
+will remove inactive lockfiles for the specified serial device, and then exit.
.TP 5
.B \-c\fP or \fB\-r\fP \fIid\fP
act as client only:
.I sympathy
-connects to a sympathy server process and injects the history into the outer terminal
+connects to a
+.I sympathy
+server process and injects the history into the outer terminal
emulator,
and connects the user with the terminal device. One server process can support multiple
client processes. This mode can also be used to obtain a dump of the current screen
-in HTML format (see the \-\fBH\fP option). The \-\fPr\fP option connects to a server
-on the socket ~/.sympathy/\fIid\fP or if \fIid\fP is an integer
-~/.sympathy/\fIhostname\fP.\fIid\fP mimicking the behaviour of screen(1). With the
-\-\fBc\fP option the socket must be specified with the \-\fBk\fP option.
+in HTML format (see the \-\fBH\fP option), inject key\-presses (see \-\fBI\fP)
+or allow control via a dumb terminal (see \-\fBN\fP).
+The \-\fPr\fP option connects to a
+server process socket called \fIid\fP, or if \fIid\fP is an integer
+\fIhost-name\fP.\fIid\fP mimicking the behaviour of screen(1).
+.I Sympathy
+searches for the socket in the following directories: \fI~/.sympathy\fP,
+\fI~/sympathy\fP, \fI/etc/sympathy\fP, \fI/var/sympathy\fP.
+With the \-\fBc\fP option the socket must be specified with the \-\fBk\fP
+option.
.TP 5
.B \fP[\fB \-c \-s \fP]
act as both client and server:
.I sympathy
-forks. The child process becomes a server, and the orginal process becomes a client
+forks. The child process becomes a server, and the original process becomes a client
which then connects to the server. This is the default major mode if no other is specified.
-Since the default terminal device is a ptty, running
+Since the default terminal device is a pseudo-tty, running
.I sympathy
-with no arguments will start a new shell in a daemonized process and connect to it
+with no arguments will start a new shell in a daemonised process and connect to it
as a client from the original process, mimicking the behaviour of screen(1)
.TP 5
.B \-l\fP or \fB\-ls
show active sockets:
.I sympathy
will show active sockets, ones to which a call to connect(2) succeeds,
-in ~/.sympathy. If the socket name begins with the hostname of the machine, and
+in ~/.sympathy. If the socket name begins with the host-name of the machine, and
the call to connect(2) fails, then socket will be unlinked.
+.TP 5
+.B \-s
+act as server only:
+.I sympathy
+opens the terminal device and renders into an internal frame buffer, listens for clients
+on the socket and logs activity. By default the server will fork into a daemon process
+but can be forced to remain in the foreground with the \-\fBF\fP option.
+.TP 5
+.B \-t
+act as terminal emulator only:
+.I sympathy
+opens the terminal device and outputs into the outer terminal emulator. When
+.I sympathy exits the
+device is closed and no process remains. In this mode
+.I sympathy
+behaves like a traditional
+terminal emulator such as cu(1) or minicom(1).
.TP 5
.B \-v
show current version:
.I sympathy
-will print the the version number of the code it was compiled with.
+will print the the version number of the code it was compiled from.
.TP 5
.B \-h
show help:
.I sympathy
doesn't
lock the terminal device, but checks periodically for lock files of other processes. If
-sympathy detects another lock file it displays \fBLocked\fP in the status line
+.I sympathy
+detects another lock file it displays \fBLocked\fP in the status line
and refuses I/O on the device until the lock file is removed or becomes invalid.
To lock the device use the \-\fBK\fP option.
.I Sympathy
The \-\fBd\fP option is incompatible with the \-\fBp\fP option.
.TP 5
.B \-p
-connect to a pseudo-tty instead of a terminal device, and fork a login shell in
-it. The \-\fBd\fP option is incompatible with the \-\fBd\fP option. This is the default
-terminal device if none is specified.
+connect to a pseudo\-tty instead of a terminal device, and fork a login shell in
+it. The \-\fBp\fP option is incompatible with the \-\fBd\fP option. This is the default
+terminal device if none is specified. The first non\-option command line
+arugment is considered to be the a binary to run in the pseudo\-tty, subsequent
+arguments are parsed to the binary. The current value of PATH is searched for
+the binary if it does not start with '/'. If no binary is specified
+then '/bin/sh' is called with \fIargv[0]\fP set to '\-'.
.TP 5
.B \-K
-lock the terminal device specificed in the \-\fBd\fP option.
+lock the terminal device specified in the \-\fBd\fP option.
.I Sympathy
generates lock files in a staggering variety of formats and places. For locks
-based on the name of the device sympathy generates lock files for all devices
-with the same major and minor in /dev, /dev/usb and /dev/tts, it uses both normal
-and lower case and replaces occurances of '/' in the device name with both '.' and '_'.
+based on the name of the device
+.I sympathy
+generates lock files for all devices
+with the same major and minor in /dev, /dev/usb and /dev/tts, it uses both
+normal and lower case and replaces occurrences of `/' in the device name with
+both `.' and `_'.
.I Sympathy
also generates locks based on the device major and minor numbers, and for all lock file
-names generates them in any of the follwoing directories that are writable:
+names generates them in any of the following directories that are writable:
/var/lock/uucp, /var/spool/lock, /var/spool/uucp, /etc/locks, /usr/spool/uucp,
/var/spool/locks, /usr/spool/lock, /usr/spool/locks, /usr/spool/uucp/LCK, /var/lock.
Lock files are assumed to be in HDB format.
.TP 5
-.B \-b \fIbaudrate\fP
-set the baud rate of the terminal device specificed in the \-\fBd\fP to baudrate, if omitted
-the current baudrate of the serial port will be used.
+.B \-b \fIbaud\-rate\fP
+set the baud\-rate of the terminal device specified in the \-\fBd\fP to
+\fIbaud\-rate\fP, if omitted the current baud\-rate of the serial port will be
+used.
.TP 5
.B \-f
-turn on flow control on the terminal device. This option add \fICRTSCTS\fP to sympathy's default
+turn on flow control on the terminal device. This option adds \fICRTSCTS\fP to
+\fIsympathy\fP's default
\fIc_cflag\fPs of \fICS8|CREAD|CLOCAL\fP.
.TP 5
.B \-L \fIlogfile\fP
-log activity to the file \fIlogfile\fP. If \fIlogfile\fP is '-' then log to \fIstdout\fP. Note
-that logging to \fIstdout\fP only makes sense with the \-\fBF\fP \fIserver_option\fP.
+log activity to the file \fIlogfile\fP. If \fIlogfile\fP is `-' then log to
+\fIstdout\fP. Note that logging to \fIstdout\fP only makes sense with the
+\-\fBF\fP \fIserver_option\fP.
+.I Sympathy
+will also close and reopen its log file when it receives a \fBSIGHUP\fP, which
+with the \fB\-P\fP allows the use of logrotate(8).
+.TP 5
+.B \-P \fIpidfile\fP
+write the pid of the server/terminal process to \fIpidfile\fP, which is
+removed on clean exit.
+.TP 5
+.B \-R
+rotate log files. When the log\-file specified with the \fB\-L\fP option
+grows large
+.I sympathy
+will rotate it and compress old log\-files.
.TP 5
.B \-w \fIwidth\fP[x\fIheight\fP]
-set the initalize size of the terminal emulator's frame buffer to be \fIwidth\fP columns
-by \fIheight\fP rows. If \fIheight\fP is ommited it defaults to 24, the default width
+set the initial size of the terminal emulator's frame buffer to be \fIwidth\fP columns
+by \fIheight\fP rows. If \fIheight\fP is omitted it defaults to 24, the default width
is 80. These values may
-be overridden later by terminal escape sequences. If \-\fBp\fP is also specificed
-the ptty will have its window size set to match.
+be overridden later by terminal escape sequences. If \-\fBp\fP is also specified
+the pseudo-tty will have its window size set to match.
.PP
.B \fIdisplay_options\fP:
.TP 5
.B \-u
-attempt to render unicode characters in the internal frame buffer to the outer terminal
+attempt to render Unicode characters in the internal frame buffer to the outer terminal
emulator by using ISO-2202 sequences.
.I Sympathy
currently only checks to see if an appropriate character appears in the VT102
-US character set, or in the VT102 'special characters and line drawing' character set.
+US character set, or in the VT102 `special characters and line drawing' character set.
If the character appears in neither of these then it will be rendered on the outer
-terminal emulator as a '?'.
+terminal emulator as a `?'.
.TP 5
.B \-H
-render the current state of the internal frame buffer to stdout as HTML, then quit.
+render the current state of the internal frame buffer to \fIstdout\fP as HTML, then quit.
+.TP 5
+.B \-N
+don't render the internal frame buffer using ANSI characters, but instead write characters
+that would be written to the screen to stdout. Take characters from stdin and send them
+to the device. This feature is useful when you wish to use sympathy in conjunction with programs
+like expect(1).
.PP
.B \fIclient_options\fP:
.TP 5
-.B -k \fIsocket\fP
-set the name in the filesystem of the socket to which
+.B \-k \fIsocket\fP
+set the name in the file-system of the socket to which
.I sympathy
-should connect. This option is \fBmanditory\fP unless the \-\fBs\fP or \-\fBr\fP options
+should connect. This option is \fBmandatory\fP unless the \-\fBs\fP or \-\fBr\fP options
have also been given. If \-\fBs\fP is given then it will default to the socket which
-the forked server process opens. See the discusion of the \-\fPr\fP option above, for
+the forked server process opens. See the discussion of the \-\fPr\fP option above, for
information on how
.I sympathy
chooses a socket name if \-\fBr\fP is specified.
+.TP 5
+.B \-I string
+Inject \fIstring\fP to the device as if it had been typed at the keyboard. Each character in
+the string is treated as a key\-press.
+.I Sympathy
+recognizes various common escapes for control characters. Other keys, for example the arrow keys,
+are mapped to character codes between 128 and 255, see src/keys.h for details.
.PP
.B \fIserver_options\fP:
.TP 5
-.B -k \fIsocket\fP
-set the name in the filesystem of the socket on which
+.B \-F
+tells the
+.I sympathy
+server process not to become a daemon but to remain the the foreground. This option is
+incompatible with the \-\fBc\fP \-\fBs\fP major mode.
+.TP 5
+.B \-k \fIsocket\fP
+set the name in the file-system of the socket on which
.I sympathy
should listen for clients. If this option is omitted
.I sympathy
will create a
-socket in ~/.sympathy, creating that directory if neccessary, and named
-\fIhostname\fP.\fIpid\fP where \fIpid\fP is the process id of the
+socket in ~/.sympathy, creating that directory if necessary, and named
+\fIhost-name\fP.\fIpid\fP where \fIpid\fP is the process id of the
.I sympathy
process that created the socket.
.TP 5
-.B -F
-tells the
-.I sympathy
-server process not to become a daemon but to remain the the foreground. This option is
-incompatible with the \-\fBc\fP \-\fBs\fP major mode.
-.TP 5
-.B -n \fInlines\fP
+.B \-n \fInlines\fP
sets the number of lines of history that the server process stores to \fInlines\fP. When
a client connects \fInlines\fP of history are injected into the outer terminal emulator
so that they can be seen when scrolling back. By default the server stores 200 lines of
history.
+.TP 5
+.B \-S
+tells the
+.I sympathy
+server process to log errors to syslog.
.SH OPERATION
When
.I sympathy
information. The first item on the line reminds you what the current escape character
is, the second indicates the terminal device to which
.I sympathy
-is connected, and the third shows the current baudrate. Other messages are:
+is connected, and the third shows the current baud\-rate. Other messages are:
.TP 5
.B Flow
indicates that that RTS/CTS flow control is in operation on the terminal device.
or removes its lock file.
.TP 5
.B n errs
-indicates the number of frames recived by the terminal device with errors. The count
-resets if no errors are detected by the device for 10 seconds.
-
-
+indicates the number of frames received by the terminal device with errors (indicating
+the wrong parity, baud\-rate or framing). The count resets if no errors are
+detected by the device for 10 seconds.
+.TP 5
+.B try higher
+.I Sympathy
+thinks that you have set the wrong baud\-rate and is unable to determine the correct
+one as the current baud\-rate is lower than the correct baud\-rate. Use the \fBbaud\fP command
+to set a higher baud\-rate (eg 115200) and
+.I sympathy
+will try again.
+.TP 5
+.B try \fIrate\fBb
+.I Sympathy
+thinks that you have set the wrong baud\-rate and thinks that the correct baud\-rate is
+\fIrate\fP. Use the \fBbaud\fP command to change the current baud\-rate.
+.SH COMMANDS
+Commands are entered by sending the escape character, ascii(7) STX, from the outer terminal
+emulator (usually by pressing CTRL\-B), typing the command and pressing return. Whilst the
+command is entered the status line changes to `:' and rudimentary line editing is available.
+Whilst the command is entered the cursor \fBdoes not move\fP but remains where the terminal
+emulator has placed it. Pressing the escape character whilst in command mode
+will send the escape character to the terminal and cancel command mode. Valid
+commands are:
+.TP 7
+.B ansi
+switch from VT102 behaviour to ANSI behaviour. The most noticeable difference is
+the so\-called `xn' glitch.
+.TP 7
+.B noansi
+switch from ANSI behaviour to VT102 behaviour.
+.TP 7
+.B baud \fInnnn\fB
+set the current baud\-rate to nnnn
+.TP 7
+.B break
+send the break signal by asserting the TX line for longer than a frame period.
+.TP 7
+.B flow
+enable RTS/CTS flow control
+.TP 7
+.B noflow
+disable RTS/CTS flow control
+.TP 7
+.B hangup
+de-assert DTR for one second.
+.TP 7
+.B width \fInn\fB
+set the current width of the screen to \fInn\fP, and reset the terminal emulator.
+.TP 7
+.B height \fInn\fB
+set the current height of the screen to \fInn\fP, and reset the terminal emulator.
+.TP 7
+.B reset
+reset the terminal emulator
+.TP 7
+.B expand
+expand the size of the screen to fit the size of the current outer terminal emulator window
+.TP 7
+.B quit
+exit this instance of
+.I sympathy
+(disconnect from the server if present)
+.SH CHARACTER ENCODINGS
+For characters between 32 and 126
+.I sympathy
+interprets them as would a VT102 terminal by following the subset of ISO-2202 that
+the VT102 supports. Characters 128 thru 255 are assumed to be in UTF\-8(7), if
+however the UTF\-8 is invalid they will instead be interpreted as characters
+from ISO_8859-1(7). Character 155 (0x9b) when not part of a valid UTF\-8 sequence
+will be interpreted as the one byte CSI character.
.PP
- you can send commands by sending
-ascii(7) STX from the outer terminal emulator (usally by pressing CTRL-B).
-
-the s
+For the outer terminal emulator
+.I sympathy
+by default issues the
+ESC % G sequence to select UTF\-8 mode and emits valid UTF-8. If the outer terminal
+does not, however, support UTF\-8 use the \-\fBu\fP switch to force
+.I sympathy
+to use the VT102 subset of ISO-2202.
.SH LOG FILES
-.SH EXIT STATUS
+Log files are made exclusively in the UTF\-8 encoding. Each line in the log file
+starts with the date and time at which the entry was made \- for example:
+.IP
+Feb 27 23:24:42.509440
+.PP
+.I Sympathy
+logs a line to the file whenever the cursor leaves the line. Additionally
+.I sympathy
+.IP \(bu 3
+logs certain other events to the file:
+.IP \(bu 3
+serial port parameter changes: baud\-rate and flow control.
+.IP \(bu 3
+serial port control line state changes.
+.IP \(bu 3
+serial port line discipline errors.
+.IP \(bu 3
+serial port errors.
+.IP \(bu 3
+suggested baud rates and bit frequency analyses.
+.IP \(bu 3
+transmission of breaks.
+.IP \(bu 3
+sending of the hangup signal (dropping the DTR line).
+.IP \(bu 3
+unknown or un\-handled messages sent on the socket.
+.IP \(bu 3
+connexion and disconnexion of clients.
+.IP \(bu 3
+reception of SIGHUP.
+.IP \(bu 3
+invalid UTF-8 sequences.
+.IP \(bu 3
+terminal size changes
+.IP \(bu 3
+un\-handled terminal command sequences
+.PP
+The log file is rotated when it gets too large if the \fI\-R\fP option
+is specified, and the log file is re-opened on receipt of a \fBSIGHUP\fP
+which together with the \fB\-P\fP allows the use of of a program such
+as logrotate(8)
+.SH AUTOMATIC BAUD RATE ALGORITHM
+If
+.I sympathy
+detects a framing error on the serial port it displays the count of
+errors on the status line, and logs the error.
+.IP
+<tty reports error: \\377 \\000 \\000>
+.PP
+The count is reset to zero after ten seconds
+have elapsed during which no errors have occurred.
+.I Sympathy
+looks at bit patterns of the characters received, and
+measures the length (in units of the receiving UART's
+bit period) of any runs of '1's delimited by '0's and vice\-versa. It
+then calculates the statistics on the length of these runs, and logs these.
+.IP
+<tty_bit_analyse: 0000000001 [0,0,0,0,0,0,110,0,0,80]>
+.PP
+For a typical
+stream of ASCII data, the most common run length will be the correct bit
+period.
+.I Sympathy
+uses this together with the current bit period to calculate the most probable
+correct baud\-rate, which is displayed in the status line, and logged.
+If the correct baud\irate is higher than the current baud\-rate then the most common bit frequency will be '0' or '1' and the correct baud\-rate cannot be
+determined. In this case sympathy will display and log the message 'try higher'.
+.IP
+<tty_analyse: 80 errors, current rate 115200b, suggest 19200b>
+.PP
+The algorithm only works well if the data stream is normal. If the data stream
+is generated by the reception, at the wrong baud\-rate, of characters emitted
+by
+.I sympathy
+then the algorithm will be biased towards suggesting that the baud\-rate
+is too low. Noise on the line will also result in sympathy concluding that
+the baud\-rate is too low.
+.SH SIGNALS
+.I Sympathy
+reacts to a set of signals. You can use the \fB-P\fP option
+to easily determine the PID of the
+.I sympathy
+process to which you would like to send a signal.
+.TP 8
+.B SIGINT
+.I Sympathy
+will immediately try to restore the outer terminal emulator to its original
+state and then exit.
+.TP 8
+.B SIGHUP
+.I Sympathy
+will close and reopen the log-file specified with the -L option, which allows
+the use of programs like logrotate(8)
+.TP 8
+.B SIGWINCH
+.I Sympathy
+will redraw the display in the outer terminal emulator so that it will fit within
+the new display size.
+.TP 8
+.B SIGCHLD
+.I Sympathy
+will wait for children if some were born (for example from compressing rotated logs)
.SH ENVIRONMENT
+.I sympathy
+uses the \fBHOME\fP environment variable to determine the default
+location for sockets.
+.br
+.I sympathy
+sets the value of \fBTERM\fP in pseudo-ttys spawned using the
+\-\fBp\fP argument to `xterm'.
+.br
+.I Sympathy
+will use \fBCSI ] 0 ;\fP to set the window title to the name of the
+socket or device if \fBTERM\fP starts with \fIxterm\fP or \fIrxvt\fP.
+.br
+The \fBPATH\fP enviroment variable is searched for the binary to be run
+in the pseudo\-tty.
+.SH EMULATION
+.I Sympathy
+completely emulates a VT102 terminal (including the VT52 emulation).
+.I Sympathy
+also emulates a few extra sequences: the xterm(1) ESC ] ... sequences, and
+the ANSI CSI @ and CSI b sequences. The numeric keypad follows exactly the
+sequences produced by an xterm rather than the exact VT102/VT220 sequences.
+.I Sympathy
+also recognises the ESC % G and the ESC % @ sequences to switch between ISO-2202
+and UTF\-8 but ignores them (see CHARACTER ENCODING below)
.SH SERIAL PORT THEORY
-.SH FILES
+A serial connexion was originally envisaged to connect a DTE (Data Terminal Equipment)
+to a DCE (Data Circuit-terminating Equipment). The DCE (some sort of modem) would assert
+the DTE's (the computer or terminal) DSR line to indicate it was ready. The DTE would
+assert DTR to indicate to the DCE that it should attempt a connexion to the remote DCE.
+Once a connexion was established the DCE would assert the DTE's CD pin. Data could then
+flow between the DTR and the remote DTE via the two DCEs. Flow control was provided
+via the RTS and CTS lines. The DTE asserts RTS when it is capable of receiving new data,
+and pauses its transmission of data when the CTS line is de-asserted. The local DCE
+asserts CTS when the remote DCE detects RTS, and vice versa.
+.PP
+In modern usage the signals are slightly different, for a typical connexion using modems
+DSR indicates that the modem is ready, a drop DTR is used to indicate to the
+modem that it should break the connexion to the remote modem. CD indicates that
+the local modem is connected to the remote modem, and CTS and RTS behave as before. Connexion
+is established by in-band signalling before CD is asserted.
+.PP
+For a \fBnull modem\fP cable local DSR and DTR are wired to remote CD, local
+CTS to remote RTS, and local RTS to remote CTS. Thus asserting local DTR
+asserts local DSR and remote CD, and asserting local RTS asserts remote CTS.
+.PP
+When RTS/CTS flow control is in operation and the receive buffer becomes full,
+the operating system, or the hardware, de-asserts RTS, causing (via the DCEs or
+the null modem cable) a de-assertion of remote CTS which in turn causes the
+remote DTE to cease transmission.
.SH EXAMPLES
-.SH ERRORS
+.PP
+using
+.I sympathy
+to mimic screen(1):
+.IP
+[foo@barhost ~]$ sympathy
+.IP
+.I Sympathy
+forks. The child becomes a daemon server and launches a new shell in a
+pseudo-tty, the original process becomes a client and connects to the server
+and shows the output. The user then uses the new shell and after some time
+either hangs up on the client or issues CTRL\-B quit, and the client detaches from
+the server.
+.IP
+Later the user wishes to retrieve her session and to determine which sympathy
+sessions are active and issues:
+.IP
+[foo@barhost ~]$ sympathy \-ls
+.br
+ /home/foo/.sympathy/barhost.8843 (Active)
+.br
+[foo@barhost ~]$
+.IP
+The user then issues:
+.IP
+[foo@barhost ~]$ sympathy \-r 8843
+.IP
+and is reconnected to her session.
+.PP
+using sympathy to mimic minicom(1):
+.IP
+.IP
+[foo@barhost ~]$ sympathy \-t \-d /dev/modem \-b 9600 \-K
+.IP
+.I Sympathy
+opens the device /dev/modem and locks it, sets the baud\-rate to 9600 baud and disables
+flow control. A VT102 terminal emulator then displays the data from the modem. The user
+quits the emulator by issuing CTRL\-B quit, which unlocks the modem and exits
+.I sympathy.
+.PP
+using
+.I sympathy
+to mimic consolidate(1):
+.IP
+.IP
+[foo@barhost ~]$ sympathy \-s \-d /dev/ttyS13 \-b 19200 \-K \-k /var/sympathy/13 \-L /var/sympathy/13.log -R
+.IP
+.I Sympathy
+becomes a daemon and detaches from the current tty. It then opens the device
+/dev/ttyS13 and locks it, sets the baud\-rate to 19200 baud and disables flow
+control.
+.I Sympathy
+then listens for clients connecting on the socket \fI/var/sympathy/13\fP, whilst logging
+completed lines and changes in status to the file \fI/var/sympathy/13.log\fP,
+rotating the log file when it gets too large.
+.IP
+A user wishing to see the current status of /dev/ttyS13 issues:
+.IP
+[foo@barhost ~]$ sympathy \-c \-k /var/sympathy/13
+.br
+or
+.br
+[foo@barhost ~]$ sympathy \-r 13
+.IP
+and the last 200 lines of history are injected into the history of her outer
+terminal emulator and she is connected to /dev/ttyS13. The user disconnects from the
+server by issuing CTRL\-B quit.
+.PP
+using
+.I sympathy
+to mimic script(1):
+.IP
+.IP
+[foo@barhost ~]$ sympathy \-t \-L typescript
+.IP
+.I Sympathy
+starts a shell in a ptty and logs completed lines to the file typescript. When the shell exits
+.I sympathy
+will terminate, or the user can press CTRL-B which will close the ptty and send a hangup
+to its controlling process.
.SH SEE ALSO
screen(1) minicom(1) consolidate(1)
.SH STANDARDS
+ANSI X3.64, ISO-6429, ECMA-48, ISO-2202, ISO-8859, ISO-10646, Digital Equipment Corp. VT102.
.SH BUGS
.PD
.IP \(bu 3
-when the \-\fBc\fP \-\fBs\fP major mode is used without the \-\fBk\fP option the pid
-used in the socket is that of the client process and therefore not unique.
+The command editor and parser should support better line editing.
+.IP \(bu 3
+It should be possible to change the escape character.
+.IP \(bu 3
+The HTML generated with the \-\fBH\fP option is ugly.
.IP \(bu 3
-the HTML generated with the \-\fBH\fP option is ugly.
-.SH SECURITY CONSIDERATIONS
+No useful error message is generated if opening the terminal device fails in the
+\-\fBc\fP \-\fBs\fP major mode.
.SH AUTHOR
+James McKenzie, sympathy@madingley.org
~ianmdlvl / sympathy.git / blobdiff