while (<FH>) {
    while ( $_ =~ m/(?:\s|\W)*([A-Za-z0-9_\.\:]+)(?:\s|\W)*/g ) {
        if ( exists $hash{$1} ) {
            $tmp = $1;
            $_ =~ s/$tmp/$hash{$tmp}/;
        }
    }
    $data .= $_;

}