c:\@Work\Perl>perl -wMstrict -le
"use Data::Dump qw(dd);
 ;;
 my @filelines = (
   '\102\105\105 B',
   '\104\125\102\131\101 W',
   '\130 EKS',
   '\132 ZEE',
   );
 ;;
 my %search_terms = map split, @filelines;
 ;;
 my %xlate =
   map { eval(qq{ qq{$_} }) => $search_terms{$_} }
   keys %search_terms
   ;
 dd \%xlate;
 ;;
 my ($search) =
   map qr{ $_ }xms,
   join ' | ',
   reverse sort
   keys %search_terms
   ;
 print $search;
 ;;
 my $s = 'the BEEroDUBYAn foX jumped the laZy dog';
 print qq{'$s'};
 ;;
 $s =~ s{ ($search) }{$xlate{ $1 }}xmsg;
 print qq{'$s'};
"
{ BEE => "B", DUBYA => "W", X => "EKS", Z => "ZEE" }

(?^msx: \132 | \130 | \104\125\102\131\101 | \102\105\105 )
'the BEEroDUBYAn foX jumped the laZy dog'
'the BroWn foEKS jumped the laZEEy dog'

##</code><code>##

c:\@Work\Perl>perl -wMstrict -le
"my $s = '>nbsp< hi nbsp there';
 print qq{'$s'};
 ;;
 $s =~ s{ nbsp }{\s}xmsg;
 print qq{'$s'};
"
Unrecognized escape \s passed through at -e line 1.
'>nbsp< hi nbsp there'
'>s< hi s there'

##</code><code>##

if($line =~ /[^[:ascii:]]/){
  $line =~ s/([^[:ascii:]])/ ... lotsa subexpressions ... /ge;
  print "Unhandled sequence: $line\n";
  }

##</code><code>##

c:\@Work\Perl>perl -wMstrict -e
"my $s = 'aXbYcZd';
 print qq{'$s' \n};
 ;;
 print qq{unhandled sequence: '$s' \n}
   if $s =~ s{ ([XYZ]) }{ sprintf '[%d/%1$#X/%1$#o]', ord $1 }xmsge;
"
'aXbYcZd'
unhandled sequence: 'a[88/0X58/0130]b[89/0X59/0131]c[90/0X5A/0132]d'

##</code><code>##

c:\@Work\Perl>perl -wMstrict -le
"use Data::Dump qw(dd);
 ;;
 my @filelines = (
   '\102\105\105 B',
   'nbsp \040',
   '\130 EKS',
   '\132 ZEE',
   );
 ;;
 my %search_terms = map split, @filelines;
 ;;
 my %xlate =
   map { eval(qq{ qq{$_} }) => $search_terms{$_} }
   keys %search_terms
   ;
 dd \%xlate;
 ;;
 my ($search) =
   map qr{ $_ }xms,
   join ' | ',
   reverse sort
   keys %search_terms
   ;
 print $search;
 ;;
 my $s = 'the BEErownbspfoX >nbsp< the laZy dog';
 print qq{'$s'};
 ;;
 $s =~ s{ ($search) }{ qq{ qq{$xlate{$1}} } }xmsgee;
 print qq{'$s'};
"
{ BEE => "B", nbsp => "\\040", X => "EKS", Z => "ZEE" }

(?^msx: nbsp | \132 | \130 | \102\105\105 )
'the BEErownbspfoX >nbsp< the laZy dog'
'the Brow foEKS > < the laZEEy dog'