Question 1

Is Perl dead in 2026?

Accepted Answer

No, but it's not growing either. Perl is in the 'COBOL phase' of its life cycle — enormous installed base that nobody's rewriting, low new-project adoption, stable jobs maintaining legacy. Booking.com, Bugzilla, Request Tracker, cPanel, and most Indian banking/telecom legacy backends still run Perl. The honest summary: don't pick Perl for a greenfield project in 2026 unless you have a specific reason (regex-heavy text processing, existing Perl team, integrating with a Perl-heavy environment). But Perl knowledge remains valuable — there's still good money in maintaining the systems that already exist.

Question 2

How much does a Perl developer earn in India?

Accepted Answer

₹5-15 LPA in 2026, with the floor higher than Python equivalents because the pool of capable Perl developers has shrunk. Senior Perl + DBA + Linux admin combinations at Indian banks, telecom (Airtel, Jio backend bits), and BPO operations (Wipro, TCS, Infosys legacy contracts) can go ₹12-18 LPA. Booking.com's Bangalore office historically paid significantly above market for Perl talent. Specialised areas (bioinformatics, Perl on Wall Street back-office systems) pay at the upper end.

Question 3

Should I learn Perl in 2026?

Accepted Answer

If you're starting your career, learn Python or JavaScript first — that's where the jobs are. Learn Perl as a second or third language if you (a) need it for a specific job, (b) work in bioinformatics or system administration, or (c) want to be able to read and maintain legacy systems. Perl 5.36+ is genuinely pleasant to write and the regex / one-liner skills transfer to every other language you'll ever use.

Question 4

When does Perl still beat Python in 2026?

Accepted Answer

Three real cases. (1) One-liners and short text-processing scripts — `perl -lane '...'` is shorter and faster than the Python equivalent. (2) Heavy regex work — Perl's regex engine is the reference implementation and has features (recursive patterns, regex variables) Python's `re` module doesn't have natively. (3) Environments where Perl is pre-installed and you can't add new dependencies — most Linux distros, most Unix servers, many embedded systems. For everything else (web apps, ML, data science, modern CLI tools), Python has the better ecosystem in 2026.

Question 5

What's the difference between Perl 5 and Perl 6/Raku?

Accepted Answer

Raku (renamed from Perl 6 in 2019) is a separate language that started as a Perl 5 successor but diverged significantly. They share aesthetics but not code — Raku is its own language with its own community and toolchain. When someone says 'Perl' in 2026 they mean Perl 5.36+, full stop. Raku has its own niche but isn't on the typical Indian enterprise stack.

Question 6

What are the three fundamental data types in Perl?

Accepted Answer

Perl has three core variable types, each with its own sigil that tells you what you're looking at: scalars ($), arrays (@), and hashes (%). A scalar holds a single value — number, string, or reference. An array is an ordered list of scalars indexed by integers. A hash is an unordered set of key-value pairs where keys are strings and values are scalars. The sigils are not just decoration: they're part of the variable's identity, which is why `$name`, `@name`, and `%name` are three completely independent variables. When you access an array element you use `$array[0]` (scalar context, scalar sigil), and a hash element is `$hash{key}` — the sigil follows the value you're getting back, not the container.

Question 7

What is context in Perl and why does it matter?

Accepted Answer

Context in Perl is the most-failed interview question because no other mainstream language has anything like it. Every expression in Perl is evaluated in either scalar context or list context, and many operators return different values depending on which one they're in. The classic example: `my @arr = (1,2,3); my $count = @arr;` — putting `@arr` on the right of a scalar assignment forces scalar context, so you get the length (3) rather than the list. In list context you'd get the list itself. The `scalar` keyword forces scalar context explicitly. This is also why `localtime()` returns a string in scalar context and a 9-element list in list context. Understanding context is the difference between writing correct Perl and writing Perl that surprises you at 3 a.m.

Question 8

What does `use strict; use warnings;` do and why should you always use them?

Accepted Answer

These two pragmas are the closest thing Perl has to a 'modern mode'. `use strict` forbids three things that legacy Perl allowed: unqualified bareword identifiers (catches typos like `prnt` vs `print`), symbolic references (using a string as a variable name), and undeclared variables (you must declare with `my`, `our`, or `state`). `use warnings` enables compile-time and runtime warnings about likely bugs: using undefined values, deprecated syntax, suspicious type conversions. In Perl 5.36+ you can replace both with `use v5.36;` which enables strict, warnings, and modern features (signatures, say) in one line. Any Perl code written without these in 2026 is a red flag — either it's pre-2000 legacy code or the author hasn't kept up.

Question 9

How do you read a file line by line in Perl?

Accepted Answer

The idiomatic approach uses a three-argument `open` (safer because it separates the mode from the filename), a `while` loop over the file handle, and `chomp` to strip the trailing newline. Always check the return value of `open` and die with an error message — file I/O failures are silent otherwise. For modern Perl, use lexical file handles (`my $fh`) rather than the old bareword form (`FH`) because they auto-close when they go out of scope and don't pollute the global namespace.

Question 10

What is `$_` (the default variable) and where does it appear?

Accepted Answer

`$_` is Perl's default scalar variable. Many built-ins read from or write to `$_` when you don't pass an explicit argument: `print`, `chomp`, regex matches (`if (/pattern/)`), `chop`, `lc`, `uc`, and most notably the `for` loop. Inside `for my $x (@arr)` you'd use `$x`; inside `for (@arr)` the current element is in `$_`. The hidden default `$_` is a major reason Perl can be terse — and a major reason it can be hard to read. Modern style prefers explicit loop variables for anything longer than a one-liner. The corresponding hidden default for arrays is `@_` (the function's argument list).

Question 11

How do you do basic regex matching and substitution in Perl?

Accepted Answer

Regex is Perl's signature feature — it's built into the language rather than living in a library. Match with `=~ m/pattern/` (the `m` is optional with `/`), substitute with `=~ s/pattern/replacement/`, and translate with `=~ tr/from/to/`. The match returns true/false in scalar context, or the captured groups in list context. Modifiers go after the closing delimiter: `i` (case insensitive), `g` (global — match all), `s` (dot matches newline), `m` (multi-line — `^`/`$` match each line), `x` (extended — whitespace and comments allowed). Capture groups are available as `$1`, `$2`, etc. after a successful match. Perl's regex engine is the reference implementation that PCRE (and through it, most other languages) copied.

Question 12

What is the difference between `my`, `our`, and `local`?

Accepted Answer

Three different scoping mechanisms with very different semantics. `my` creates a lexically-scoped variable — visible only inside the enclosing block, the most common and safest choice. `our` creates a package-scoped global — visible across the entire package, mostly used for module-level constants and configuration. `local` is the weird one: it doesn't create a new variable, it saves the existing package variable's value, lets you change it temporarily, and restores it when the block exits. `local` is what you need when monkey-patching special variables like `$/` (the input record separator). Modern code uses `my` for almost everything. Interview-wise, the common trap is using `our` when `my` is meant, exposing internals you didn't intend to.

Question 13

How do you define and call a subroutine with arguments?

Accepted Answer

Classic Perl receives arguments in the `@_` array — you unpack with `shift` or list assignment. Modern Perl (5.20+, stable since 5.36) supports native signatures, which look like Python or JavaScript parameters. Signatures also validate arity — calling with the wrong number of arguments dies. For new code in 2026, use signatures; for reading old code, remember `@_` is the implicit list of all arguments.

Question 14

How do you check if a key exists in a hash?

Accepted Answer

Use the `exists` function. The common trap: `if ($hash{key}) { ... }` is true only when the value is also truthy, so it misses keys with values of 0, empty string, or undef. `exists` checks only whether the key is in the hash, regardless of value. For 'has a value AND it's defined', use `defined($hash{key})`. For 'key exists' use `exists`. For 'value is truthy' use the plain boolean — but be sure that's what you mean.

Question 15

What is CPAN and how do you install modules?

Accepted Answer

CPAN (Comprehensive Perl Archive Network) is Perl's package repository — older and arguably more comprehensive than PyPI or npm. It hosts 200,000+ modules covering everything from web frameworks to bioinformatics. The recommended installer in 2026 is `cpanm` (App::cpanminus) for ad-hoc installs and `carton` for project-level dependency pinning (analogous to npm's package-lock.json). For system Perl, prefer your distro's package manager (`apt install libfoo-perl`) for core modules; for project Perls use `perlbrew` + `cpanm` + `carton`. Avoid the old interactive `cpan` shell — it works but the UX is from 1995.

Perl Interview Questions

What are the three fundamental data types in Perl?

What is context in Perl and why does it matter?

What does `use strict; use warnings;` do and why should you always use them?

How do you read a file line by line in Perl?

What is `$_` (the default variable) and where does it appear?

How do you do basic regex matching and substitution in Perl?

What is the difference between `my`, `our`, and `local`?

How do you define and call a subroutine with arguments?

How do you check if a key exists in a hash?

What is CPAN and how do you install modules?

How do you join and split strings in Perl?

What is interpolation in Perl strings?

What are references in Perl and how do you use them?

How does Perl handle OOP? Compare classic Perl OOP, Moose, and Moo.

What's the difference between `=~` and `!~`?

What are regex modifiers and when do you use them?

How do you connect Perl to a database with DBI?

What's the difference between `map`, `grep`, and `for` in Perl?

What is a closure in Perl?

How do you write a Perl one-liner to process a log file?

What is the autovivification problem in Perl?

How does Perl handle exceptions?

What is the difference between `wantarray`, scalar, and void context inside a subroutine?

What are slices in Perl?

How do you debug Perl code in production? Data::Dumper, Carp, and the debugger.

How do you write a CPAN-quality Perl module in 2026?

How do you profile and optimize slow Perl code?

How do you build a modern web app in Perl? (Mojolicious vs Catalyst vs Dancer)

How do you handle concurrency in Perl? Threads vs forks vs async (IO::Async/Mojo::IOLoop)?

How do you call Perl from other languages or call C from Perl?

Companies Hiring Perl

Salary Insights

Frequently Asked Questions

Is Perl dead in 2026?

How much does a Perl developer earn in India?

Should I learn Perl in 2026?

When does Perl still beat Python in 2026?

What's the difference between Perl 5 and Perl 6/Raku?

Introduction