You can search for any group of strings you wish to. The problem is, what are the possible values. Will it be the English name or the German on: Germany or Deutchland? Will it be the current name or an older one: Myamar or Burma? Sri Lanka or Ceylon? Mumbai or Bombay?

If you have a file with one value per line, you can use "grep -f countries datafile" to examine datafile for all the countries in the countries file. The perl equivalent is simple:

• read in the set of countries into an array
• form into a regular expression which will capture the found string:

  my $re_text = join '|', map {($_)} @countries;
  my $re = rx/$re_text/;
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• and then test each input line against the re:

  while ( my $line = <$fh>) {
      chomp $line;
      my $found = ($line =~ /$re/);
      # Profit!
  }
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