Fixed duplicate in Perl sheet.

perl.md

@@ -19,125 +19,6 @@ $scalar_variable = 42;
 %hash_variable   = ('key' => 'value');
 ```
 
-## Control Structures
-
-### if-else
-```perl
-if ($condition) {
-    # Code to execute if condition is true
-} else {
-    # Code to execute if condition is false
-}
-```
-
-### foreach
-```perl
-foreach $item (@array) {
-    # Code to execute for each item in the array
-}
-```
-
-### while
-```perl
-while ($condition) {
-    # Code to execute while condition is true
-}
-```
-
-## Subroutines
-
-```perl
-sub greet {
-    my $name = shift;
-    print "Hello, $name!\n";
-}
-
-greet("Alice");
-```
-
-## Regular Expressions
-
-### Matching
-```perl
-if ($string =~ /pattern/) {
-    # Code to execute if pattern is found in $string
-}
-```
-
-### Substitution
-```perl
-$string =~ s/find/replace/;
-```
-
-## File Handling
-
-### Open and Read
-```perl
-open(my $file, '<', 'filename.txt') or die "Can't open file: $!";
-while (<$file>) {
-    chomp;
-    print "$_\n";
-}
-close($file);
-```
-
-### Open and Write
-```perl
-open(my $file, '>', 'output.txt') or die "Can't open file: $!";
-print $file "Hello, File!\n";
-close($file);
-```
-
-## Modules
-
-### Using Modules
-```perl
-use Module::Name;
-```
-
-### Exporting Functions
-```perl
-use Module::Name qw(function1 function2);
-```
-
-## References
-
-### Scalar Reference
-```perl
-$scalar_ref = \$scalar_variable;
-```
-
-### Array Reference
-```perl
-$array_ref = \@array_variable;
-```
-
-### Hash Reference
-```perl
-$hash_ref = \%hash_variable;
-```
-
-# Advanced Perl Cheat Sheet
-
-## Basics
-
-### Comments
-```perl
-# This is a comment
-```
-
-### Print
-```perl
-print "Hello, World!\n";
-```
-
-### Variables
-```perl
-$scalar_variable = 42;
-@array_variable  = (1, 2, 3);
-%hash_variable   = ('key' => 'value');
-```
-
 ### Data Types
 ```perl
 $string = "Perl";