#WBL 28 March 2012 $Revision: 1.00 $

#usage:

BEGIN {
#  v = "$Revision: 1.2 $";
#  print "#replaced.awk",substr(v,2,length(v)-2),strftime();
  for(j=1;j<ARGC;j++) {
    printf("%s -> ",ARGV[j]);
    for(i=length(ARGV[j]);i>0;--i) {
      printf("%s",complement(substr(ARGV[j],i,1)));
    }
    printf("\n");
  }
}

function complement(x) {
  x=toupper(x);
  if(x=="A") return "T";
  if(x=="C") return "G";
  if(x=="G") return "C";
  if(x=="T") return "A";
  return "n";
}