Version 4 of tclsh application template

This template code is for starting a typical tclsh application.

 #! /bin/sh
 # the next line restarts using tclsh \
 exec tclsh "$0" ${1+"$@"}

This is a little more sophisticated than the code suggested on the tclsh man page (see tcl), and is explained in great detail on exec magic.

Typical patterns to continue are:

   * verify Tcl version requirements
 package require Tcl 8.4    ;# My application uses [lset]
   * process stdin:
 while {[gets stdin line]>=0} {
   #do something with $line
 }
   * process argv:
 foreach arg $argv {
   # do something with $arg
 }