unless|until|LABEL|{}|last|next|redo| || |//|i++|++i

 #!/usr/bin/perl

 use strict;
 use warnings;

 $_ = 'oireqo````';

 unless($_ =~ /^a/m){print "no match to a\n"}

 #no match to a

 if(!($_ =~ /^a/m)){print "no match to a\n"}

 #no match to a

 unless($_ =~ /^o/m){print "no match to a"}else{print "match!\n"}

 my $number = ;

 while($number<)
 {
     $number++;print "$number\n";
 }

 #2
 #3
 #4
 #5
 #6
 #7
 #8
 #9
 #10
 #11
 #12

 until($number<)
 {
     $number--;print "$number\n"
 }

 #11
 #10
 #9
 #8
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 #6
 #5
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 #3
 #2
 #1

 print "match!\n"if($_ =~ /^o/m);

 #match!

 my @arr=(,,,,,,);print foreach(@arr);print"\n";

 #1234567

 #my @arr_1=(1,2,3,4,5,6,7);print"$k" foreach my $k($#arr_1);print"\n";
 #Global symbol "$k" requires explicit package name (did you forget to declare "my $k"?) at t.pl line 62.
 #syntax error at t.pl line 62, near "$k("
 #Execution of t.pl aborted due to compilation errors.

 {
     my $k = "good";
 }
 #print "$k\n";

 #Global symbol "$k" requires explicit package name (did you forget to declare "my $k"?) at t.pl line 70.
 #Execution of t.pl aborted due to compilation errors.

 my @fruit = ('apple','banana','peach','apple','apple');my %match;$match{$_}++ foreach(@fruit);print "$match{$_}\n"foreach(keys %match);

 #1
 #1
 #3

 my $five_1= ;my $six_1 = $five_1++;print "$six_1\t$five_1\n";
 my $five_2= ;my $six_2 = ++$five_2;print "$six_2\t$five_2\n";

 #5       6
 #6       6

 my %seen;foreach(@fruit) {print "i 've get $_!\n" if $seen{$_}++;}

 #i 've get apple!
 #i 've get apple!

 for($_ = "abcdefg";s/(.)//;){print "$1\n";if($ eq "f"){last;}}

 #a
 #b
 #c
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 #f
 my %seen;

 READ:while(<>)
 {
     foreach(split)
     {
         next READ if /\W/;$seen{$_}++;
     }
 }

 foreach (keys %seen){print "last:$_ is $seen{$_}\n";last if /dewm/;}
 foreach (keys %seen){print "next:$_ is $seen{$_}\n";next if /dewm/;}
 #foreach (keys %seen){print "redo:$_ is $seen{$_}\n";redo if /dewm/;}

 # cat 1.txt
 # shsjsk   123
 # dewm
 # shsjsk   123
 #  shsjsk   123
 #  shsjsk   123
 # cat 1.txt |perl t.pl
 #last:shsjsk is 4
 #next:shsjsk is 4
 #next:123 is 4
 #next:dewm is 1
 #redo:dewm is 1
 #……

 my $zero = ;my $one = ;
 if (($zero != )&&($one%$zero==)){print "get!\n"}

 #

 my %zoo;$zoo{'fish'}='cat',$zoo{'mouse'} ='dog';$zoo{'dog'}="";
 my $animal=$zoo{'dog'}||'nobody';print "$animal\n";
 my $animal_1=$zoo{'panda'}||'nobody';print "$animal_1\n";
 my $animal_2=defined $zoo{'dog'}? '1':'nobody';print "$animal_2\n";
 my $animal_3=$zoo{'dog'}//'nobody';print "$animal_3\n"; 

 #nobody
 #nobody
 #1
 #

 printf "%s\n",$animal_3//'nobody';

 #

 my $m =;($m>)||print "$m\n";

 #

 $m> or die "wrong judgement";

 #wrong judgement at t.pl line 152, <> line 5.