serial terminal emulator
tip is used to connect to another system
over a serial link. In the era before modern networks, it was typically used
to connect to a modem in order to dial in to a remote host. It is now
frequently used for tasks such as attaching to the serial console of another
machine for administrative or debugging purposes.
The options are as follows:
- No escape (disable tilde).
- Set verbose mode.
If speed is specified, it will override any baudrate specified in the system description being used.
If neither speed nor
system-name are specified,
system-name will be set to the value of the
HOST environment variable.
If speed is specified but
system-name is not, system-name
will be set to a value of 'tip' with speed appended.
tip -1200 will set
system-name to 'tip1200'.
Line access is logged to /var/log/aculog. This file does not exist by default and has to be created to enable logging.
Typed characters are normally transmitted directly to the remote
machine (which does the echoing as well). A tilde
~’) appearing as the first character
of a line is an escape signal; the following are recognized:
- Drop the connection and exit. Only the connection is dropped – the login session is not terminated.
- Change directory to name (no argument implies change to home directory).
- Escape to a shell (exiting the shell will return to
- Copy file from local to remote.
tipprompts for the name of a local file to transmit.
- Copy file from remote to local.
tipprompts first for the name of the file to be sent, then for a command to be executed on the remote machine.
- Send a file to a remote UNIX host. This command
causes the remote UNIX system to run the following
command string, sending it the ‘from’ file:
stty -echo; cat > 'to'; stty echo
If the ‘to’ file isn't specified, the ‘from’ file name is used. This command is actually a UNIX specific version of the
- Take a file from a remote UNIX host. As in the
~pcommand, the ‘to’ file defaults to the ‘from’ file name if it isn't specified. The remote host executes the following command string to send the file to
cat 'from'; echo '' | tr '\012' '\01'
- Pipe the output from a remote command to a local UNIX process. The command string sent to the local UNIX system is processed by the shell.
- Pipe the output from a local UNIX process to the remote host. The command string sent to the local UNIX system is processed by the shell.
- Fork a child process on the local system to perform special protocols such
as XMODEM. The child program will be run with the following arrangement of
0 <-> remote tty in 1 <-> remote tty out 2 <-> local tty stderr
- Send a
BREAKto the remote system. For systems which don't support the necessary
ioctl() call, the break is simulated by a sequence of line speed changes and DEL characters.
- Set a variable (see the discussion below).
- List all variables and their values (if set).
tip(only available with job control).
- Stop only the “local side” of
tip(only available with job control); the “remote side” of
tip, the side that displays output from the remote host, is left running.
- Get a summary of the tilde escapes.
To find the system description, and thus the operating
characteristics of system-name,
tip searches for a system description with a name
identical to system-name. The search order is
- If the environment variable
REMOTEdoes not start with a ‘
/’ it is assumed to be a system description, and is considered first.
- If the environment variable
REMOTEbegins with a ‘
/’ it is assumed to be a path to a remote(5) database, and the specified database is searched.
- The default remote(5) database, /etc/remote, is searched.
See remote(5) for full documentation on system descriptions.
The br capability is used in system
descriptions to specify the baud rate with which to establish a connection.
If the value specified is not suitable, the baud rate to be used may be
given on the command line, e.g. ‘
The dv capability is used to specify the device with which to establish a connection. For reasons outlined in tty(4), cua(4) devices should be used on architectures which have them. For those which do not, tty(4) devices can be used. Users in group “dialer” are permitted to use cua(4) devices by default; permissions on /dev/tty00 or /dev/ttya can be changed, but they will revert to their defaults after an upgrade or (re)install.
tip establishes a connection, it
sends out the connection message specified in the cm
capability of the system description being used.
tip prompts for an argument, for
example during setup of a file transfer, the line typed may be edited with
the standard erase and kill characters. A null line in response to a prompt,
or an interrupt, will abort the dialogue and return the user to the remote
tip guards against multiple users
connecting to a remote system by opening modems and terminal lines with
exclusive access, and by honoring the locking protocol used by
During file transfers
tip provides a
running count of the number of lines transferred. When using the
the “eofread” and “eofwrite” variables are used
to recognize end-of-file when reading, and specify end-of-file when writing
(see below). File transfers normally depend on hardwareflow or tandem mode
for flow control. If the remote system does not support hardwareflow or
tandem mode, “echocheck” may be set to indicate
tip should synchronize with the remote system on the
echo of each transmitted character.
tip maintains a set of variables which
control its operation. Some of these variables are read-only to normal users
(root is allowed to change anything of interest). Variables may be displayed
and set through the ‘s’ escape. The syntax for variables is
patterned after vi(1) and
Mail(1). Supplying “all” as an argument to the set
command displays all variables readable by the user. Alternatively, the user
may request display of a particular variable by attaching a
?’ to the end. For example,
“escape?” displays the current escape character.
Variables are numeric, string, character, or boolean values.
Boolean variables are set merely by specifying their name; they may be reset
by prepending a ‘
!’ to the name. Other
variable types are set by concatenating an
=’ and the value. The entire
assignment must not have any blanks in it. A single set command may be used
to interrogate as well as set a number of variables. Variables may be
initialized at run time by placing set commands (without the
~s’ prefix) in the initialization
file ~/.tiprc; the
tip to display the sets as they
are made. Certain common variables have abbreviations. The following is a
list of common variables, their abbreviations, and their default values:
- (num) The baud rate at which the connection was established; abbreviated ba.
- (bool) Discard unprintable characters when a session is being scripted; abbreviated be.
- (bool) Synchronize with the remote host during file transfer by waiting for the echo of the last character transmitted; default is off.
- (str) The set of characters which signify an end-of-transmission during a
~<file transfer command; abbreviated eofr.
- (str) The string sent to indicate end-of-transmission during a
~>file transfer command; abbreviated eofw.
- (str) The set of characters which indicate an end-of-line.
tipwill recognize escape characters only after an end-of-line.
- (char) The command prefix (escape) character; abbreviated
es; default value is
- (str) The set of characters which should not be discarded due to the beautification switch; abbreviated ex; default value is “\t\n\f\b”.
- (char) The character used to force literal data transmission; abbreviated
fo; default value is
- (num) The amount of data (in bytes) to buffer between filesystem writes when receiving files; abbreviated fr.
- (bool) Whether hardware flow control (CRTSCTS) is enabled for the
connection; abbreviated hf; default value is
- (str) The name of the host to which you are connected; abbreviated ho.
- (num) The line discipline to use; abbreviated ld.
- (char) The character which indicates an end-of-line on the remote host;
abbreviated pr; default value is
\n’. This value is used to synchronize during data transfers. The count of lines transferred during a file transfer command is based on receipt of this character.
- (bool) Upper case mapping mode; abbreviated ra;
default value is off. When this mode is enabled, all
lowercase letters will be mapped to uppercase by
tipfor transmission to the remote machine.
- (char) The input character used to toggle uppercase mapping mode;
abbreviated rc; default value is
- (str) The name of the file in which a session script is recorded; abbreviated rec; default value is “tip.record”.
- (bool) Session scripting mode; abbreviated sc;
default is off. When script is
tipwill record everything transmitted by the remote machine in the script record file specified in record. If the beautify switch is on, only printable ASCII characters will be included in the script file (those characters between 040 and 0177). The variable exceptions is used to indicate characters which are an exception to the normal beautification rules.
- (bool) Expand tabs to spaces during file transfers; abbreviated tab; default value is false. Each tab is expanded to 8 spaces.
- (bool) Use XON/XOFF flow control to throttle data from the remote host; abbreviated ta. The default value is true unless the nt capability has been specified in /etc/remote, in which case the default value is false.
- (bool) Verbose mode; abbreviated verb; default is
true. When verbose mode is enabled,
tipprints messages while dialing, shows the current number of lines transferred during a file transfer operations, and more.
- The home directory to use for the
- The default value for system-name if none is specified via the command line.
- A system description, or an absolute path to a remote(5) system description database.
- The name of the shell to use for the
~!command; default value is “/bin/sh”.
- initialization file
- record file
- global remote(5) database
- line access log
- lock file
tip command appeared in
The full set of variables is undocumented and should, probably, be pared down.