$ perl -le'"foo" =~ /(foo)/; print $1; "bar" =~ /(bar)/; print $1;'
foo
bar

##</code><code>##

$ perl -le'"foo" =~ /(foo)/; print $1; "bar" =~ /(bar)/; print $1; "baz" =~ /(quux)/; print $1;'
foo
bar
bar

##</code><code>##

while(<DATA>) {
    if( $_ =~ /(foo)/ ) {
        print "$.: $1 -- $&\n";
    }
    else {
        print "No match on line $..\n"
    }
}