SPLITVT(1) NONESSENTIAL UTILITIES SPLITVT(1)
NAME
splitvt - run two shells in a split window
SYNOPSIS
splitvt [options] [shell]
OPTIONS
-upper command Runs 'command' in the upper window
-lower command Runs 'command' in the lower window
-s numlines Sets 'numlines' to the number of lines
in the top window. This number will be modified if the
screen isn't big enough to handle the full size.
-t title Sets an xterm title bar to 'title'
-login Runs the programs under each window as though they
were login shells. This is useful to have csh source
it's .login file, bash source .profile, etc.
-nologin Ovverrides any "set login on" statement
in the startup file.
-rcfile file Loads 'file' as the startup file
instead of ~/.splitvtrc. If %s is present in the filename,
it will be replaced by your home directory. (E.g.
%s/.splitvtrc is equivalent to the default startup
file)
-norc Suppresses loading your ~/.splitvtrc
-v Print out the version number of splitvt
DESCRIPTION
This program splits the screen into two windows, one above
the other, and runs a shell in each one. The default
shell is taken from the SHELL environment variable, or
/bin/csh if SHELL isn't in the environment, but another
shell can be specified on the command line.
The top window is the default current window, but you can
change to the other by pressing ^W. Pressing ^V will
quote the next character to the current shell. Pressing
^O will put splitvt into command mode.
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These special characters (command mode, switch window, and
quote next character) can be modified from within the
.splitvtrc file.
When in command mode, splitvt will read one non-numeric
character, perform the requested command, and then revert
to normal operations. Numeric characters are interpreted
as a parameter for the specified command. The currently
supported commands are:
'h' Print a help window for the escape commands
'-' Shrink the current window
'+' Expand the current window
'c' Select a block of text in the current window
'p' Paste the selected text to the current window
'k' Kill the current window (hangup signal)
'x' Lock the screen, after prompting for password
'r' Repaint the screen (clearing screen garbage)
'q' Quickly quit splitvt, killing the running shells
More functions may be added in the future.
If the -s command line option is used, the upper window
will be bound to the user defined number of lines even if
the screen is resized. Otherwise, the screen will be
split into two equal parts based on the new size of the
screen.
The environment variable SPLITVT is set in the shells
forked by splitvt. In the shell running in the upper win-
dow, this variable is set to the value "upper", while the
shell running in the lower window has this variable set to
the value "lower". This is useful in shell scripts to
provide different behavior depending on which window the
script is running in. An example of this is shown in the
file "menu" in the examples directory in the splitvt dis-
tribution.
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When splitvt starts up, it looks in your home directory
for a file named .splitvtrc You can set a number of param-
eters from within this file, including all of the special
characters, the default number of lines in the upper win-
dow, whether or not to run the commands as login shells,
and even default commands to run in each window.
Here is an example of a .splitvtrc file:
# This is an example .splitvtrc file. set
command_char ^O set quote_char ^V set
switch_char ^W set upper_lines 12 run
-upper /bin/sh run -lower top set
login on # This next line would override the above
run statements #run /bin/tcsh
If programs like vi are doing strange things to the window
while in splitvt, you probably need to set the LINES envi-
ronment variable to a correct value, or set the terminal's
window sizing correctly. This should be done automati-
cally, but may need to be corrected.
If you are running under an xterm window, the title bar
will probably be updated to show the version of splitvt
that you are running. Under a true xterm window, you can
also switch which half of the window you are typing into
by clicking the mouse in the half of the window in which
you want to type. You can also drag and drop the separa-
tor bar by pressing down on the mouse button over the sep-
arator bar, holding it down, moving the mouse to where you
want the bar to end up, and then releasing the button.
splitvt will attempt to erase the current utmp entry, and
replace it with entries for the two windows. This allows
you to use programs such as 'talk' within the splitvt win-
dows. If you do not have write permission to the
/etc/utmp file, you will not be able to modify the utmp
entries.
splitvt can be made set-uid root. splitvt will reset its
user id to that of the person running it, just before it
exec()'s the shell under the window. The splitvt process
remains with root permissions, and will change ownership
of the pseudo terminals to that of the person running
splitvt, and then reset it to root when the window is
closed.
SPLITVT IS NOT GUARANTEED TO BE A SAFE SET-UID PROGRAM!
I have done all I know to keep splitvt a safely usable
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set-uid program, but I do not know everything, and am not
responsible for any security weaknesses splitvt might
posess.
BUGS
When used with a certain public domain version of ksh, you
have to manually kill -9 on the shell processes after you
quit splitvt. This has to do with a bug in that version
of ksh (Version 06/03/86a and possibly others).
If splitvt is compiled with xterm support, when run under
an xterm, the cut and paste feature is semi-disabled. The
title bar may also be reset to the string "xterm" after
splitvt quits. See the comments at the top of splitvt.c
for how to disable xterm support.
Ansi colors are not repainted on screen refresh.
CAVEATS
There may be conflicts between splitvt's characters and
other programs. You can either change splitvt's default
characters with command line options, or you can type
Ctrl-V (the quote character) within splitvt, and the next
character typed will be sent to the current window, no
matter what it is.
splitvt can only be used by terminals using vt100 emula-
tion, due to the use of specific vt100 escape codes.
(vt300, xterm, Linux console, etc, emulation also works)
When running in an xterm, if you press the escape key, you
will have to type another character in order for the
escape to be seen by the running program.
AUTHOR
Sam Lantinga slouken@cs.ucdavis.edu
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