perl -e "use 5.012; my $foo='now is the time for'; if ( $foo =~ /[meit]+/ && $foo =~ /[^a]{1,20}/ ) { say 'true';} else {say 'nope';}"
true

##</code><code>##

perl -e "use 5.012; my $bar = 'abcdefg'; if ($bar =~ /[a-d]/ && $ bar !~ /[ef]/ ){ say 'true';} else {say 'false';}"
false