Updated April 5, 2023
Introduction to Perl interview questions
Perl is a general-purpose programming language originally developed for text manipulation and now used for a wide range of tasks including system administration, web development, network programming, GUI development, and more.
What are interview questions?
An interview is essentially a structured conversation in which one party asks questions and the other response. Formalized paraphrase the term “interview” is commonly used to refer to a one-on-one conversation between an interviewer and an interviewee. The interviewer poses questions to the interviewee, who usually responds by providing information.
Part 1 – Perl Interview Questions and Answers (Basic)
This first part covers basic Interview Questions and Answers.
Q1. Which functions in Perl allows you to include a module file or a module and what is the difference between them?
Answer:
“use”
- The method is only used for modules (only to include.pm type files)
- The included objects are verified during the compilation
- The file extension is not required.
- loads the module during compilation.
“require”
- The method is applicable to both libraries and modules, and the included objects are validated at run time.
- The file Extension must be specified.
- Loads at run time
For example;
If we have a module file named “Module.pm,” we can use Module;
Q2. Some arguments are frequently utilised in Perl. What these are and what do these arguments mean?
Answer:
W (argument shows warning)
D (use for debug)
C (which compile only not run)
E (which executes)
Combination of these can also be used as: -wd
Q3. Which guidelines by Perl modules must be followed?
Answer:
These are the guidelines
- The package’s name should always start with a capital letter.
- The extension “.pm” should be present throughout the file name.
- The package should be derived from the Exporter if no object-oriented method is employed.
- Also, if no object-oriented approaches are employed, the module’s functions and data should be exported
- Modules are loaded using this method).
Q4. How the interpreter is used in Perl?
Answer:
In order to run, every Perl programme must go via the Perl interpreter. In many Perl applications, the opening line is something like:
#!/usr/bin/perl
Internally, the interpreter compiles the programme into a parse tree. The programme interpreter will ignore any words, spaces, or marks after the pound symbol. The interpreter immediately executes it after transforming it to a parse tree. Although Perl is usually referred to as an interpreted language, it is not.
This is absolutely correct. Because the interpreter converts the programme into byte code before it is executed, It is frequently referred to as an interpreter/compiler because it executes it.
Q5. In Perl, what are the meanings of -w, -t, and strict?
Answer:
When we use –w, we get a warning regarding probable script interpretation issues. Strict tells Perl to enforce checks on variable definitions and usage. The use strict command can be used to do so. If the script contains any dangerous or unclear instructions, this pragma will stop the script from running instead than only delivering warnings. When –t is used, taint checking is enabled. It compels Perl to check the origin of variables in subshell executions and system calls when outside variables aren’t allowed.
Part 2 – Perl Interview Questions and Answers (Advanced)
Let us now have a look at the advanced Interview Questions and Answers.
Q6. For a situation in programming, how can you determine that Perl is a suitable?
Answer:
If you require a faster execution time, Perl will meet your needs. If you want to create a web-based application, you have a number of options when it comes to programming. We do not need to purchase a Perl licence because it is available for free. We can utilise CPAN (Comprehensive Perl Archive Network), which is one of the most popular Perl distributions and one of the world’s largest open code repositories.
Q7. What is the difference between chop and chomp function.?
Answer:
Chop and Chomp are both used to remove the last character from an expression and each element of a list, however in the case of chomp, chomp will only follow the elimination phrase if the values of the components match. That is why it is best to chomp rather than chop.
Q8. Can code be used in the Perl repeatedly? If so, what is the user’s option?
Answer:
Yeah, in Perl it’s possible. The use of the same code in the same programme, however, is limited. Even as Perl comes with a code trimming feature, the users need not worry about the complexity. It guides users automatically how to keep your code short. A prime example of this is code reusability. “Inheritance” is the feature that allows users to keep pace with this.
Q9. Write syntax to use grep function?
Answer:
grep BLOCK LIST
grep (EXPR, LIST)
Q10.What is the use of -n and -p options?
Answer:
Scripts are wrapped inside loops using the -n and -p parameters. The -n option instructs Perl to run the script within the loop. The -p option employed the same loop as the -n option, but it also used to continue. When both the -n and -p options are used at the same time, the -p option takes precedence.
Q11. In Perl, how many different types of operators are there?
Answer:
Assignment operators: +, –, *
Arithmetic operators: +, –, *
Operators for incrementing and decrementing:
++ and —
Concatenation of strings:
operator ‘.’
operators for comparison:
==, !=, >, < , >=
Logical operators are the following:
&&, ||, !
Q12. Tell the Associate Arrays in Perl something and how important they are to the programmers?
Answer:
It is essentially one of Perl’s most frequently used data type after Scalar and Array. They are very like a hash table and there are a lot of functions that are quite like the same one.
Q13. What are the advantages of C over Perl?
Answer:
C has a larger number of development tools than PERL. PERL programmes are slower to execute than C programmes. Although Perl looks to be an interpreted language, the code is generated dynamically. In contrast to C, if you don’t want anyone to use your Perl code, you must hide it in some way. It is difficult to create a Perl programme executable without the use of extra tools.
Q14. What is use of ‘->’ symbol?
Answer:
The infix dereference operator in Perl is the ‘->’ symbol. The left-hand side must be a reference if the right-hand side is an array subscript, hash key, or function.
@array = qw/ abcde/; # array
print "n",$array->[0]; # it is wrong
print "n",$array[0]; #it is correct , @array is an array
Q15. What does the’$_’ symbol mean?
Answer:
The ‘$_’ is a default variable in Perl and $_ is known as the “default input and pattern matching space
Conclusion
All this is about some good questions and responses for developers for Perl interviews. This list is a good way to measure your skills if you start learning Perl. A good development partner from Perl should be able with a little study and practice to answer all these questions without much difficulty. You can also read a good Perl text to learn more about such issues as Modern Perl.
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