PERL Interview Questions and Answers in 2025 (100+ Q&A)

PERL System Security Engineer

Ques:- What is meant 'die' in a perl program?

Asked In :- disclosure and barring service dbs, gbs,

Right Answer:
In Perl, 'die' is a function that terminates the program and prints an error message.

PERL System Integrator

Ques:- What does the word '&myvariable' mean?

Asked In :-

Right Answer:
In Perl, `my $variable` declares a new, lexically scoped variable named `$variable`.

PERL System Security Engineer

Ques:- What's is the use of 'require' and what does this mean?

Asked In :-

Right Answer:
In Perl, `require` is used to include and execute a module or a file at runtime. It checks if the file has already been loaded; if not, it loads it, allowing you to use the functions and variables defined in that file.

PERL System Security Engineer

Ques:- What is a DataHash(). What does it mean? and for what purpose it is used??

Asked In :- travis ci,

Right Answer:
`DataHash()` is a function in Perl used to create a hash (associative array) from a data structure, typically for the purpose of generating a unique identifier or checksum for that data. It helps in efficiently comparing data structures or storing them in a way that allows for quick lookups and retrievals.

PERL System Integrator

Ques:- What does this mean :'$_' ?

Asked In :-

Right Answer:
`$_` is the default variable in Perl that holds the current value being processed in loops and other operations.

PERL System Integrator

Ques:- What is meant by a 'pack' in perl?

Asked In :-

Right Answer:
In Perl, a 'pack' is a function that converts a list into a binary structure, allowing you to create a string representation of data in a specific format, such as integers, floats, or strings, based on a template.

PERL System Integrator

Ques:- What's the purpose of -w.strict,-T?

Asked In :-

Right Answer:
The `-w` flag enables warnings, `-strict` enforces strict coding rules, and `-T` enables taint mode in Perl, which helps ensure that data from outside the program is properly validated before use.

PERL System Integrator

Ques:- What does new $cur->{LINK} do?

Asked In :-

Right Answer:
`new $cur->{LINK}` creates a new instance of the object or class referenced by the `LINK` attribute of the `$cur` object.

PERL System Integrator

Ques:- Why we use Perl?

Asked In :- Octro,

Right Answer:
We use Perl for its powerful text processing capabilities, ease of use for scripting, strong support for regular expressions, and versatility in system administration, web development, and data manipulation tasks.

PERL System Integrator

Ques:- How do I set environment variables in Perl programs?

Asked In :-

Right Answer:
You can set environment variables in Perl using the `%ENV` hash. For example:

```perl
$ENV{'VARIABLE_NAME'} = 'value';
```

This sets the environment variable `VARIABLE_NAME` to `value`.

PERL System Integrator

Ques:- What does Perl do if you try to exploit the execve(2) race involving setuid scripts?

Asked In :-

Right Answer:
Perl will not execute the setuid script if it detects a race condition involving execve(2). Instead, it will raise an error and refuse to run the script to prevent security vulnerabilities.

PERL System Integrator

Ques:- What are scalar data and scalar variables?

Asked In :-

Right Answer:
Scalar data in Perl refers to a single value, which can be a number, a string, or a reference. Scalar variables are variables that hold scalar data and are denoted with a dollar sign ($) followed by the variable name, such as `$variable`.

PERL System Integrator

Ques:- What is Perl one-liner?

Asked In :-

Right Answer:
A Perl one-liner is a short Perl program that is executed from the command line, typically consisting of a single line of code, often used for quick text processing or data manipulation tasks.

PERL System Integrator

Ques:- How to turn on Perl warnings? Why is that important?

Asked In :-

Right Answer:
To turn on Perl warnings, use the `-w` flag when running your script, or include `use warnings;` at the beginning of your Perl code. This is important because it helps identify potential issues and bugs in your code, making it easier to debug and maintain.

PERL System Integrator

Ques:- I have a variable named $objref which is defined in main package. I want to make it as a Object of Class XYZ. How could I do it?

Asked In :-

Right Answer:
You can create an object of class XYZ and assign it to the variable $objref like this:

```perl
$objref = XYZ->new();
```

PERL System Integrator

Ques:- How do you give functions private variables that retain their values between calls?

Asked In :-

Right Answer:
You can use a closure in Perl to create private variables that retain their values between calls. Define a subroutine that contains the private variable, and return another subroutine that modifies or accesses that variable. Here's an example:

```perl
sub create_counter {
my $count = 0; # Private variable
return sub {
$count++; # Increment and return the count
return $count;
};
}

my $counter = create_counter();
print $counter->(); # Outputs: 1
print $counter->(); # Outputs: 2
```

PERL System Integrator

Ques:- How many ways can we express string in Perl?

Asked In :-

Right Answer:
In Perl, we can express a string in several ways:

1. Double quotes (`"string"`)
2. Single quotes (`'string'`)
3. Here-documents (`<<EOF ... EOF`)
4. Quoting operators (like `q//`, `qq//`, `qx//`, `qw//`, etc.)
5. String concatenation using the dot operator (`.`)

These methods allow for different behaviors regarding variable interpolation and escape sequences.

PERL System Integrator

Ques:- What happens when you return a reference to a private variable?

Asked In :-

Right Answer:
When you return a reference to a private variable in Perl, the reference allows access to that variable outside its scope, but if the variable goes out of scope, the reference may lead to undefined behavior or errors when accessed.

PERL System Integrator

Ques:- What is hash in perl?

Asked In :-

Right Answer:
A hash in Perl is a data structure that stores key-value pairs, allowing you to associate a unique key with a specific value. It is created using the `%` symbol and can be accessed using the keys.

PERL System Integrator

Ques:- Which of these is a difference between C++ and Perl?

Asked In :- holberton school,

Right Answer:
C++ is a compiled language, while Perl is an interpreted language.

PERL, which stands for “Practical Extraction and Reporting Language,” is a powerful and highly versatile programming language that was initially developed for text processing and reporting. Created by Larry Wall in 1987, it has evolved into a general-purpose, interpreted language used across a wide range of applications, from system administration to web development. Despite the emergence of newer languages, PERL remains a robust and enduring tool, particularly for tasks that require rapid development and powerful text-handling capabilities.

The core strength of PERL lies in its exceptional text manipulation engine. It has a rich and highly integrated set of features for regular expressions, making it an ideal choice for tasks like parsing log files, extracting data from unstructured text, and generating reports. Its syntax is C-like, which makes it familiar to many programmers, but it also boasts unique features that allow for concise and expressive code. PERL supports both procedural and object-oriented programming paradigms, providing developers with the flexibility to choose the most suitable style for their projects.

A key feature that distinguishes PERL is the Comprehensive Perl Archive Network (CPAN). This vast repository of over 250,000 open-source modules allows developers to easily extend the language’s functionality, with modules available for virtually every task, from database connectivity and web frameworks to complex data analysis. This extensive library ecosystem has cemented PERL’s reputation as a “glue language” capable of connecting disparate systems and automating complex workflows. PERL’s applications are diverse, spanning from its traditional use in system administration and network management to its role in web development and scientific computing, making it a valuable tool for programmers and engineers in many different fields.

Questions in: PERL

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