0. INTRODUCTION
This is a port and cleanup of my bash debugger bashdb
(http://bashdb.sf.net). 
 
The command syntax generally follows that of the GNU debugger gdb.
 
However this debugger depends on a number bug fixes and of debugging
support features that are neither part of the POSIX 1003.1 standard
and only in ksh93t+ releases. In particular, there are fixes to a
number of the .sh variables like .sh.level and .sh.file.
 
1. SETUP
 
To get the code, install git and run in a ksh shell:
 
  git-clone git://github.com/rocky/kshdb.git
  cd kshdb
  ./autogen.sh  # Add configure options. See ./configure --help 
 
If you've got a suitable ksh93t installed, then
  make && make test
 
To try on a real program such as perhaps /etc/profile:
  ./kshdb /etc/profile # substitute /etc/profile with your favorite ksh script
 
If you are happy and "make test" above worked, install via:
  sudo make install
 
and uninstall with 
  sudo make uninstall # ;-)
 
See INSTALL for generic configure installation instructions.
 
2. WHAT'S HERE, WHAT'S NOT and WHY NOT
 
What's missing falls into a two categories:
 
  * Stuff that can be ported in a straightforward way from bashdb
  * Stuff that needs additional ksh support
 
Of the things which can be ported in a straight-forward way, however
some of them I want to revise and simplify. In some cases, the fact
that ksh has associative arrays simplifies code. On other cases, the
code I wrote needs refactoring and better modularization.
 
Writing documentation is important, but an extensive guide will have
to wait. For now one can consult the reference guide that comes with
bashdb: http://bashdb.sf.net/bashdb.html There is some minimal help to
get a list of commands and some help for each.
 
3. WHAT'S NOT HERE YET IN DETAIL
 
3.a) Showing frame arguments
 
This can done with or without support from ksh, albeit faster with
help from ksh.
 
3.b) Setting $0
 
3.c) lots of other stuff including...
 
  display expressions, signal handling, 
  debugger commands:
     debug
     condition
     file
     handle
     history
     pwd
     signal
     tty
     watch
 
  None of this is rocket science. Should be pretty straight-forward to
  add.
 
4. WHAT MAY NEED MORE WORK AND SUPPORT FROM KSH
 
4.a) stopping points that can be used for breakpoint