Hidden features of Perl?

while(<$fh>)
{
  next if 1..1; # skip first record
  ...
}

$ perl -wle 'my $x = 3; print $ x'
 3

$ perl -lwe '*4 = sub { print "yes" }; 4->()'
yes

$ perl -wle 'print !!4'
1
$ perl -wle 'print !!"0 but true"'
1
$ perl -wle 'print !!0'
(empty line)

$ perl -Mstrict  -wle 'print q bJet another perl hacker.b'
Jet another perl hacker.

m xabcx
# same as m/abc/

s{
    ^            # make sure to get whole filename
    (
      [^'] +     # at least one non-quote
      .         # extension dot
      (?:        # now either suffix
          gz
        | Z
       )
    )
    z           # through the end
}{gzcat '$1' |}xs for @ARGV;

while (<>) {
    print;
}

$x = $a || $b;

 # $x = $a, if $a is true.
 # $x = $b, otherwise

$x = $a || $b || $c || 0;

my $_ = "a"
print -$_

my $_ = "a"
print -$_

my $_ = "a"
print -$_

print ++$_

$_ = 'z'
print ++$_

*My::Namespace:: = %Your::Namespace

my $method = 'foo';
my $obj = My::Class->new();
$obj->$method( 'baz' ); # calls $obj->foo( 'baz' )

*foo = sub { print "Hello world" };

use subs 'unlink';
sub unlink { print 'No.' }

BEGIN{
    *CORE::GLOBAL::unlink = sub {print 'no'}
};

unlink($_) for @ARGV

my $url = q{http://my.url.com/any/arbitrary/path/in/the/url.html};

my $var  = q#some string where the pound is the final escape.#;
my $var2 = q{A more pleasant way of escaping.};
my $var3 = q(Others prefer parens as the quote mechanism.);

my $var4 = qq{This "$mechanism" is broken.  Please inform "$user" at "$email" about it.};

my $output  = qx{type "$path"};      # get just the output
my $moreout = qx{type "$path" 2>&1}; # get stuff on stderr too

sub MyRegexCheck {
    my ($string, $regex) = @_;
    if ($string)
    {
       return ($string =~ $regex);
    }
    return; # returns 'null' or 'empty' in every context
}

my $regex = qr{http://[w].com/([w]+/)+};
@results = MyRegexCheck(q{http://myurl.com/subpath1/subpath2/}, $regex);

my @allowed = qw(A B C D E F G H I J K L M N O P Q R S T U V W X Y Z { });
   my @badwords = qw(WORD1 word2 word3 word4);
   my @numbers = qw(one two three four 5 six seven); # works with numbers too
   my @list = ('string with space', qw(eight nine), "a $var"); # works in other lists
   my $arrayref = [ qw(and it works in arrays too) ];

for ($item)
{
    s/&‎nbsp;/ /g;
    s/<.*?>/ /g;
    $_ = join(" ", split(" ", $_));
}

my @list = ('abc', 'def', 'ghi', 'jkl');

my @list = qw(abc def ghi jkl);

print 1, 2, 3, ;

print
    results_of_foo(),
    results_of_xyzzy(),
    results_of_quux(),
    ;

my @lines = <DATA>;
for (@lines) {
    print if /bad/;
}

__DATA__
some good data
some bad data
more good data
more good data

sub do_stuff_with_a_hash (&%) {
    my ( $block_of_code, $hash_ref ) = @_;
    while ( my ( $k, $v ) = each %$hash_ref ) {
        $block_of_code->( $k, $v );
    }
}

use Data::Dumper;


do_stuff_with_a_hash {
    local $Data::Dumper::Terse = 1;
    my ( $k, $v ) = @_;
    say qq(Hey, the key   is "$k"!);
    say sprintf qq(Hey, the value is "%v"!), Dumper( $v );


} %stuff_for
;

perl -MLib::DB -MLib::TL -e 'run_expensive_database_delete() if $hour_of_day < AM_7';

my $old_die_handler = $SIG{__DIE__};
$SIG{__DIE__}
    = sub { say q(Hey! I'm DYIN' over here!); goto &$old_die_handler; }
    ;

overload::constant
    integer => sub {
        my $lit = shift;
        return $lit > 2_000_000_000 ? Math::BigInt->new( $lit ) : $lit
    };

print '-' x 80;     # print row of dashes

print for (1, 4, 9) x 3; # print 149149149

ls |perl -lne 'print $_; }{ print "$. Files"'

LINE: while (defined($_ = <ARGV>)) {
    print $_; }{ print "$. Files";
}

$a = 5 <=> 7;  # $a is set to -1
$a = 7 <=> 5;  # $a is set to 1
$a = 6 <=> 6;  # $a is set to 0

while( <> ){
  print "top of loopn";
  chomp;

  next if /next/i;
  last if /last/i;

  print "bottom of loopn";
}continue{
  print "continuen";
}

while(/G(bw*b)/g) {
     print "$1n";
}

while (<>) {
...			# code for each line
}

BEGIN {
    eval {
        require 'config.local.pl';
    };
    if ($@) {
        require 'config.default.pl';
    }
}

rename("$_.part", $_) for "data.txt";

print ~~ localtime;

print scalar localtime;

print localtime;

SKIP: {
    skip() if $something;

    print "Never printed";
}

sub skip {
    no warnings "exiting";
    last SKIP;
}

local $SIG{__WARN__} = sub { die @_ };
$num = "two";
$sum = 1 + $num;
print "Never reached";

$_ = "foo bar";
my $count =()= /[aeiou]/g; #3

sub foo {
    return @_;
}

$count =()= foo(qw/a b c d/); #4