

          cmdtrace level|on [noeval] [notruncate] [flush] [procs]
               Print a trace statement for all commands executed at
               depth of level or below (1 is the top level).  If on is
               specified, all commands at any level are traced.  The
               following options are available:

               noeval
                    Causes arguments to be printed unevaluated.  If
                    noeval is specified, the arguments are printed
                    before evaluation.  Otherwise, they are printed
                    afterwards.

                     If the command line is longer than 60 characters,
                    it is truncated to 60 and a "..." is postpended to
                    indicate that there was more output than was
                    displayed.  If an evaluated argument contains a
                    space, the entire argument will be enclosed inside
                    of braces (`{}') to allow the reader to visually
                    separate the arguments from each other.

               notruncate
                    Disables the truncation of commands and evaluated
                    arguments.

               flush
                    Causes the output buffer to be flushed after each
                    line is printed.  This is useful when tracing C
                    code that cause an application to abort, making it
                    easy to narrow the problem down to the command
                    that caused the abort.

               procs
                    Enables the tracing of procedure calls only.
                    Commands that aren't procedure calls (i.e. calls
                    to commands that are written in C, C++ or some
                    object-compatible language) are not traced if the
                    procs option is specified.  This option is
                    particularly useful for greatly reducing the
                    output of cmdtrace while debugging.

               filehandle
                    If specified, then the trace output will be
                    written to the file rather than stdout.

          cmdtrace off
               Turn off all tracing.

          cmdtrace depth
               Returns the current maximum trace level, or zero if
               trace is disabled.
