in reply to regex return true instead of false

your ! has higher precedence than =~ , please note the (parens) due to -p flag in B::Deparse 

d:\exp>perl -MO=Deparse,-p -e"if (! $args =~ /\-rs(\s+)(\S+)/ && ! $ar
+gs =~ /\-p(\s+)(\S+)/ && ! $args =~ /\-P(\s+)(\S+)/){1}"

if (((((!$args) =~ /\-rs(\s+)(\S+)/) and ((!$args) =~ /\-p(\s+)(\S+)/)
+) and ((!$args) =~ /\-P(\s+)(\S+)/))) {
    '???';
}
-e syntax OK

[download]

I'd say either use not instead of ! or just !~ instaed of =~

and I'd also recommend using and instead of &&

EDIT

you might be interested in reading

Cheers Rolf
(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery FootballPerl is like chess, only without the dice

Replies are listed 'Best First'.
Re^2: regex return true instead of false (precedence)
by Ratazong (Monsignor) on Aug 26, 2019 at 13:52 UTC

    The easiest way to get around precedence-issues is to define precedence yourself by using (a lot of) brackets. So 

    unless (! $args =~ /\-rs(\s+)(\S+)/ && ! $args =~ /\-p(\s+)(\S+)/ && !
+ $args =~ /\-P(\s+)(\S+)/) {

    [download]
    will become 
    unless ((!($args =~ /\-rs(\s+)(\S+)/)) && (!($args =~ /\-p(\s+)(\S+)/)
+) && (!($args =~ /\-P(\s+)(\S+)/))) {

    [download]
    I agree it looks a bit confusing, but modern editors help you by showing the matching bracket. And you don't have to think about rules (which might be counter-intuitive (like ! vs =~) or different in other programming languages).

    HTH, Rata

[reply]
[d/l]
[select]
      I agree that it's better to over use brackets than forgetting them.

      On the other hand there's a good reason why Perl has that many operators.

      And, not, or won't bite you in Boolean expressions because they have the lowest precedence. (But I use brackets when combining them, I need a complicated mnemonic to remember that and has higher precedence than or)

      And !~ is really underused.

      Cheers Rolf
      (addicted to the Perl Programming Language :)
      Wikisyntax for the Monastery FootballPerl is like chess, only without the dice

[reply]
      I prefer to use indenting to make all the parens more clear. Also, this "unless not" syntax can be confusing.
      I think I got this right, but it is easy to make a mistake. Consider:
      # X is the "default action"

# do X with an exception that when A,B and C are all false
# then don't do X

unless (!A and !B and !C) {X}

# if anybody is true then they all can't be false
# so we do X unless anybody is true (meaning they
# can't all be false)

unless (A or B or C) {X}
-------

unless ( (!($args =~ /\-rs(\s+)(\S+)/)) && 
         (!($args =~ /\-p(\s+)(\S+)/))  && 
         (!($args =~ /\-P(\s+)(\S+)/))     ) 
   {.....

# I figure this is easier to understand:

unless ( $args =~ /\-rs(\s+)(\S+)/ or 
         $args =~ /\-p(\s+)(\S+)/  or 
         $args =~ /\-P(\s+)(\S+)/     ) 
   {....

      [download]
[reply]
[d/l]

        If you break a condition like that over multiple lines (and for a complicated or long condition I recommend it) put the operators at the front of the lines so they don't get "lost" at the back:

        if (  $args =~ /\-rs(\s+)(\S+)/
   || $args =~ /\-p(\s+)(\S+)/
   || $args =~ /\-P(\s+)(\S+)/
   )

        [download]
        Optimising for fewest key strokes only makes sense transmitting to Pluto or beyond
[reply]
[d/l]

In Section Seekers of Perl Wisdom