KIBITZ(1)
NAME
kibitz - allow two people to interact with one shell
SYNOPSIS
kibitz [ kibitz-args ] user [ program program-args... ]
kibitz [ kibitz-args ] user@host [ program program-args...
]
INTRODUCTION
kibitz allows two (or more) people to interact with one
shell (or any arbitrary program). Uses include:
+o A novice user can ask an expert user for help.
Using kibitz, the expert can see what the user
is doing, and offer advice or show how to do it
right.
+o By running kibitz and then starting a full-
screen editor, people may carry out a conversa-
tion, retaining the ability to scroll back-
wards, save the entire conversation, or even
edit it while in progress.
+o People can team up on games, document editing,
or other cooperative tasks where each person
has strengths and weaknesses that complement
one another.
USAGE
To start kibitz, user1 runs kibitz with the argument of
the user to kibitz. For example:
kibitz user2
kibitz starts a new shell (or another program, if given on
the command line), while prompting user2 to run kibitz.
If user2 runs kibitz as directed, the keystrokes of both
users become the input of the shell. Similarly, both
users receive the output from the shell.
To terminate kibitz it suffices to terminate the shell
itself. For example, if either user types ^D (and the
shell accepts this to be EOF), the shell terminates fol-
lowed by kibitz.
Normally, all characters are passed uninterpreted. How-
ever, if the escape character (described when kibitz
starts) is issued, the user may talk directly to the kib-
itz interpreter. Any Expect(1) or Tcl(3) commands may be
given. Also, job control may be used while in the inter-
preter, to, for example, suspend or restart kibitz.
Various processes can provide various effects. For exam-
ple, you can emulate a two-way write(1) session with the
command:
kibitz user2 sleep 1000000
ARGUMENTS
kibitz takes arguments, these should also be separated by
whitespace.
The -noproc flag runs kibitz with no process underneath.
Characters are passed to the other kibitz. This is par-
ticularly useful for connecting multiple interactive pro-
cesses together. In this mode, characters are not echoed
back to the typist.
-noescape disables the escape character.
-escape char sets the escape character. The default
escape character is ^].
-silent turns off informational messages describing what
kibitz is doing to initiate a connection.
-tty ttyname defines the tty to which the invitation
should be sent.
If you start kibitz to user2 on a remote computer, kibitz
performs a rlogin to the remote computer with your current
username. The flag -proxy username causes rlogin to use
username for the remote login (e.g. if your account on the
remote computer has a different username). If the -proxy
flag is not given, kibitz tries to determine your current
username by (in that order) inspecting the environment
variables USER and LOGNAME, then by using the commands
whoami and logname.
The arguments -noescape and -escape can also be given by
user2 when prompted to run kibitz.
MORE THAN TWO USERS
The current implementation of kibitz explicitly under-
stands only two users, however, it is nonetheless possible
to have a three (or more) -way kibitz, by kibitzing
another kibitz. For example, the following command runs
kibitz with the current user, user2, and user3:
% kibitz user2 kibitz user3
Additional users may be added by simply appending more
"kibitz user" commands.
The xkibitz script is similar to kibitz but supports the
ability to add additional users (and drop them) dynami-
cally.
CAVEATS
kibitz assumes the 2nd user has the same terminal type and
size as the 1st user. If this assumption is incorrect,
graphical programs may display oddly.
kibitz handles character graphics, but cannot handle
bitmapped graphics. Thus,
% xterm -e kibitz will work
% kibitz xterm will not work
However, you can get the effect of the latter command by
using xkibitz (see SEE ALSO below). kibitz uses the same
permissions as used by rlogin, rsh, etc. Thus, you can
only kibitz to users at hosts for which you can rlogin.
Similarly, kibitz will prompt for a password on the remote
host if rlogin would.
If you kibitz to users at remote hosts, kibitz needs to
distinguish your prompt from other things that may precede
it during login. (Ideally, the end of it is preferred but
any part should suffice.) If you have an unusual prompt,
set the environment variable EXPECT_PROMPT to an
egrep(1)-style regular expression. Brackets should be
preceded with one backslash in ranges, and three back-
slashes for literal brackets. The default prompt r.e. is
"($|%|#) ".
kibitz requires the kibitz program on both hosts. kibitz
requires expect(1).
By comparison, the xkibitz script uses the X authorization
mechanism for inter-host communication so it does not need
to login, recognize your prompt, or require kibitz on the
remote host. It does however need permission to access
the other X servers.
BUGS
An early version of Sun's tmpfs had a bug in it that
causes kibitz to blow up. If kibitz reports "error flush-
ing ...: Is a directory" ask Sun for patch #100174.
If your Expect is not compiled with multiple-process sup-
port (i.e., you do not have a working select or poll), you
will not be able to run kibitz.
ENVIRONMENT
The environment variable SHELL is used to determine the
shell to start, if no other program is given on the com-
mand line.
If the environment variable EXPECT_PROMPT exists, it is
taken as a regular expression which matches the end of
your login prompt (but does not otherwise occur while
logging in). See also CAVEATS above.
If the environment variables USER or LOGNAME are defined,
they are used to determine the current user name for a
kibitz to a remote computer. See description of the -proxy
option in ARGUMENTS above.
SEE ALSO
Tcl(3) libexpect(3) xkibitz(1)
"Exploring Expect: A Tcl-Based Toolkit for Automating
Interactive Programs" by Don Libes, O'Reilly and Associ-
ates, January 1995.
"Kibitz - Connecting Multiple Interactive Programs
Together", by Don Libes, Software - Practice & Experience,
John Wiley & Sons, West Sussex, England, Vol. 23, No. 5,
May, 1993.
AUTHOR
Don Libes, National Institute of Standards and Technology
kibitz is in the public domain. NIST and I would appreci-
ate credit if this program or parts of it are used.