use strict; use warnings ;

  my $z = <DATA> ;
  printf "\$z=%s, ~\$z=%s\n", show($z), show(~$z) ; 

  sub show {
    return '"'. join('', map { sprintf('\\x%02X', ord($_)) } split(//, $_[0])) .'"' ;
  } ;  

  __DATA__
  0x1234