c:\@Work\Perl\monks>perl -wMstrict -le
"use 5.010;
 ;;
 use Data::Dumper qw(Dumper);
 ;;
 my $data = qq{Foo bar -baz boff eid- 1234 gkn 12-34_loanmaster\n}
          . qq{Fizz :faz foz6 eid - 4532 gkn 34-21-hostmasfer\n}
          . qq{Do :not capture xeid - 999 gkn 34-21-xxx\n}
          . qq{Also do :not capture eid999 gkn 34-21-xxx\n}
          . qq{eid 762 biff bam1 zot@\n}
          ;
 print qq{[[$data]] \n};
 ;;
 my $separator = qr{ \s* - \s* | \s+ }xms;
 ;;
 my $captured_eids =
 my @EIDs = $data =~ m{ \b eid $separator \K \d+ }xmsg;
 ;;
 if ($captured_eids) {
   print 'captured EID(s): ', Dumper \@EIDs;
   }
 else {
   print 'no EIDs captured';
   }
"
[[Foo bar -baz boff eid- 1234 gkn 12-34_loanmaster
Fizz :faz foz6 eid - 4532 gkn 34-21-hostmasfer
Do :not capture xeid - 999 gkn 34-21-xxx
Also do :not capture eid999 gkn 34-21-xxx
eid 762 biff bam1 zot@
]]

captured EID(s): $VAR1 = [
          '1234',
          '4532',
          '762'
        ];