DB<100> @patterns=qw#one two three#
 
  DB<101> $str="one two"
 
  DB<102> $re=join "|",@patterns
 
  DB<103> print $str =~ m/($re)/g
onetwo

##</code><code>##

  DB<106> $str="two one two"
 
  DB<107> print $str =~ m/($re)/g
twoonetwo
  DB<108> print grep {$str=~/$_/} @patterns
onetwo