Perl Interview Questions and Answers 2025

Perl is a high-level, general-purpose, interpreted programming language.

Scalar variables in Perl are declared using the $ symbol.

'use strict;' helps catch errors and enforce good coding practices.

An array in Perl is created using the @ symbol.

'my' declares a variable with a lexical scope, while 'our' declares a global variable.

Strings in Perl can be concatenated using the '.' operator.

CPAN is the Comprehensive Perl Archive Network, a repository of Perl modules.

Comments in Perl start with the # symbol.

A hash is a collection of key-value pairs, declared using the % symbol.

Array elements are accessed using their index in square brackets.

'chomp' removes the newline character from the end of a string.

Files in Perl are opened using the 'open' function.

'eq' is used for string comparison, while '==' is used for numeric comparison.

Subroutines in Perl are defined using the 'sub' keyword.

The default variable in Perl is $_.

Context in Perl determines how an expression is evaluated, either in scalar or list context.

'require' is used at runtime, while 'use' is evaluated at compile time.

Exceptions in Perl are handled using 'eval' blocks.

'bless' associates an object with a class in Perl.

Packages in Perl are created using the 'package' keyword.

Regular expressions in Perl are used for pattern matching and text manipulation.

Arguments are passed to a subroutine via the special array @_.

'die' terminates the program, while 'warn' issues a warning and continues execution.

References in Perl are created using the backslash operator and dereferenced using the appropriate symbol.

'AUTOLOAD' is used to handle undefined subroutine calls dynamically.

Object-oriented programming in Perl is implemented using packages, 'bless', and method calls.

'local' temporarily backs up and replaces global variables, while 'my' creates lexically scoped variables.

Filehandles in Perl are used to read from or write to files and are created using the 'open' function.

'tie' binds a variable to a package class to override its behavior.

Modules in Perl are included using the 'use' or 'require' statements.

Closures in Perl are subroutines that capture and use variables from their surrounding scope.

Perl uses reference counting for garbage collection to manage memory.

Polymorphism in Perl is achieved through method overriding in object-oriented programming.

The 'DESTROY' method is called automatically when an object goes out of scope.

Anonymous subroutines in Perl are created using the 'sub' keyword without a name.

'can' checks if an object can perform a method, while 'isa' checks if it belongs to a class.

Circular references in Perl can be handled using the 'weaken' function from Scalar::Util.

The 'eval' function in Perl is used to catch runtime errors or execute code dynamically.

The 'overload' pragma in Perl is used to define custom behavior for operators in objects.

Typeglobs in Perl are used to create aliases for variables or filehandles.

The 'SUPER' keyword in Perl is used to call a method from a parent class.

Inheritance in Perl is implemented by setting the @ISA array in a package.

The 'UNIVERSAL' package provides default methods for all Perl classes.

Threads in Perl are created and managed using the 'threads' module.

A shallow copy duplicates references, while a deep copy duplicates the entire data structure.

The 'DBI' module in Perl is used to connect to and interact with databases.

The 'lock' function in Perl is used to manage shared variables in threaded programs.

Perl code can be profiled using the 'Devel::NYTProf' module.

'BEGIN' runs code during compilation, and 'END' runs code at program termination.

The 'Moose' framework simplifies object-oriented programming by providing modern features.