CodeSubmit Interview Series

The 10 Best Perl Interview Questions in 2023

What are the top Perl interview questions? Today, you’ll get the top questions to ask at your next interview. Want to learn more? Read on!

Interviewing Perl developers 

Perl is a general-purpose, stable, and open-source programming language. It was originally developed for text manipulation but is today used for tasks such as web development, network programming, and administration. The acronym Perl stands for Practical Extraction and Report Language. 

But how do you find the top Perl developers for your projects? Let’s take a look at the top interview questions here below. 

Beginner Perl interview questions

What are the best Perl interview questions for junior developers? Here’s what you need to know about beginner questions for Perl developers. 

1. What are the main features of Perl? 


Perl borrows its best features from other languages such as C and BASIC. Perl works with HTML, XML, and other markup languages. It also supports Unicode and is Y2K compliant. Perl’s database interface DBI supports third-party databases including Oracle, MySQL, Sybase, and more. 

Perl supports procedural and object-oriented programming, and it interfaces with external C and C++ libraries through XS and SWIG. There are over 20,000 third-party modules available in Perl. 

2. What are the main benefits and disadvantages of Perl? 


The top advantages of Perl are that it’s an efficient and easy-to-use language with text manipulation capabilities and a rapid development cycle. As an interpreted language, it’s also interpreted statement-by-statement. And it’s portable and can be used cross-platform. 

Perl handles encrypted web data, and it can be embedded into web servers to speed up processing by up to 2,000%. This language allows the Apache web server to embed a Perl interpreter. The Perl DBI package makes web-database integration easy.

The top disadvantage is that Perl is an interpreted language so the execution speed is slow, and it can’t be used to write complex code. 

3. Explain what a Perl reference is. 


A Perl reference is a scalar data type. It holds the location of another value, which can be scalar, arrays, or hashes. A reference can be used anywhere where a scalar can be used.

Senior Perl interview questions

Next, let’s look at the top Perl interview questions for senior developers. These questions are created for more advanced developers. 

4. Explain what numeric operators are in Perl.


The numeric operators in Perl are: 

  • Arithmetic operators (+,-,*/)
  • Bitwise operators (&(and), |(or),^(ex-or),~(not),<<(shift left),>>(shift right))
  • Comparison operators to compare two numbers (>, <, ==, !=,<=,>=,<=>)

Arithmetic operators perform from left to right. Bitwise operators perform from right to left. 

5. What is the difference between an array and a list? 


Array and list are defined as a set of elements, but they differ in that a list is immutable (it can’t be altered directly). An array, again, is mutable and its contents can grow, shrink, and so on. 

Ultimately, an array is a list without a name. The contents of a list can be changed by storing the list as an array. Arrays provide dynamic storage for lists. 

6. What functions in Perl let you include a module file or a module? 


The functions in Perl that allow you to include a module file or module are:


The “use” method is used for modules only to include a .pm type file. Objects are verified at the time of compilation and the file extension doesn’t need to be specified. “Use” loads the module at compile time. 


The “require” method is used for libraries and modules and the included objects are verified at run time. The file extension needs to be verified and it loads at run-time. 


or requires “”

7. Explain what a Perl identifier means. 


Perl programs consist of a series of statements and declarations that run from top to bottom with control structures, such as loops and subroutines, that allow you to bounce around the code. 

Perl identifiers are the names that are used to identify classes, variables, functions, modules, and other objects. These variable names begin with $, @, or % followed by letters, zero, underscores, or digits (0-9). Identifiers can’t contain punctuation characters such as @, %, or $.

8. Can you load binary extensions in Perl dynamically? 


Yes, you can use a dynamic approach to load binary extensions as long as your system supports it. Otherwise, you can undertake the task statically.

A dynamic load is important when your program determines at runtime that it requires more functionalities than are available. As a result, it loads it and continues to run. 

Dynamically loaded binary extensions can help save time because users can perform basic tasks according to their preferences. 

9. Explain what -w, -t, and strict mean. 


-w generates a warning regarding probable script interpretation issues. 

By using strict, again, you tell Perl to enforce checks on variable definitions and usage. However, if the script includes dangerous or unclear instructions, the script will stop running and only deliver warnings. 

-t is used to enable taint checking. It compels Perl to check the origin of variables in subshell executions and system calls in case variables are not permitted. 

10. Explain scalar data and variables. 


Data type concepts are flexible. Scalar is a single thing, such as a string or a number. Scalar is similar to Java concepts such as float, string, or double. Strings and numbers are exchangeable. A scalar variable is essentially a Perl variable that is used to store scalar data. 

Over to you!

There you have it! Now you know what the top Perl interview questions are. 

These questions will help you find the right candidate for your project. However, interviewing is just one part of a technical process. 

You also need to assess your candidates’ technical skills. 

That’s where CodeSubmit can help. CodeSubmit offers technical assessment and live coding interview tests that help you identify the top candidates for your team.

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