#!/usr/bin/gawk -f
# /* vim: set filetype=gawk : */ -*- awk -*- 

BEGIN{
  FS = ",";
  Fname="test";
  Src = 3;
  Out="";
}

{
  temp = $NF;
  $NF = $Src;
  $Src = temp;
  gsub(/ +/,",");
  gsub(/\t+/,",");  
  Out= Out $0 "\n";
}

END{
  print Out>Fname;
}