Perl

Overview

Perl is a high-level, interpreted, dynamically typed programming language created by Larry Wall in 1987 while he was working at Unisys. It was designed as a practical tool for report generation and text manipulation, drawing syntax and ideas from C, sed, awk, and the Bourne shell. The language became central to early web development in the 1990s — for a time, “Perl CGI script” was synonymous with server-side scripting on the public web.

The reference implementation is perl itself, maintained by the Perl 5 Porters (p5p) and overseen by The Perl Foundation. Perl 5 remains the actively developed line, with regular releases (5.40 shipped in 2024). Raku, originally announced as Perl 6, was renamed in 2019 and is now a separate language with its own community and toolchain.

Where it is actually used

Perl still runs significant infrastructure rather than greenfield projects. The Debian package toolchain (dpkg, dh, much of debian/rules glue) is Perl. cPanel, the hosting control panel running on a large share of shared web hosts, is largely a Perl codebase. Bugzilla, RT (Request Tracker), and Movable Type are long-standing Perl applications still in use. Booking.com is publicly known as one of the largest Perl shops in production. The Bioinformatics community uses Perl through BioPerl for sequence parsing and pipeline glue, and Ensembl’s genome browser backend is written in Perl. Inside Git itself, several porcelain tools (git-svn, git-send-email, gitweb) are Perl scripts. System administrators continue to use it for log parsing, ad-hoc reporting, and one-off migration scripts where regex throughput matters.

Strengths

Perl’s regular expression engine is among the most capable in any general-purpose language; PCRE — the library that brought Perl-compatible regex to PHP, Nginx, and many others — exists because Perl set the de facto standard. Text munging in Perl tends to be terse and fast: perl -ne, perl -pi -e, and the implicit $_ and @ARGV make one-liners genuinely shorter than the equivalent in Python or Ruby.

CPAN is the other historical strength. It predates pip, npm, and RubyGems by years, and offers a uniform packaging, testing, and documentation model (Module::Build, prove, perldoc) that the language ships with rather than bolts on. Perl’s Taint mode and strict/warnings pragmas allow defensive scripting that catches a class of mistakes at compile time. The language is highly stable — code written for Perl 5.8 in 2002 generally still runs on 5.40.

Trade-offs and weaknesses

Perl rewards conciseness in ways that punish readers. Sigil context ($, @, %), implicit variables, and “there’s more than one way to do it” mean two engineers can produce code that looks unrelated while doing the same thing. Object orientation was retrofitted on top of references and blessed hashes; the modern alternative, Moose, is heavy at startup and Moo is a workaround for that weight. A long-promised native object system (use feature 'class') only landed experimentally in 5.38.

Hiring is a real concern — the pool of new developers writing Perl is small, and university curricula moved on years ago. Performance for numeric workloads is poor compared to compiled languages, and Perl has no usable concurrency story beyond fork and IO::Async; threads exist but are widely advised against. Unicode handling is correct but historically confusing, requiring explicit use utf8 and :encoding layers.

Notable libraries / ecosystem

• Moose — a full-featured object system with roles, type constraints, and method modifiers; the basis for much modern Perl OO code.
• DBI — the standard database interface, with DBD drivers for PostgreSQL, MySQL, SQLite, Oracle, and ODBC.
• Mojolicious — a real-time web framework with built-in non-blocking I/O, WebSocket support, and zero non-core dependencies.
• Dancer2 — a lighter Sinatra-style web framework, often chosen for small services and APIs.
• DBIx::Class — an ORM built on DBI, with a relational result-set model rather than active-record.
• Test::More and prove — the testing harness shipped with most distributions; the TAP protocol it produced is now consumed by tools in many other languages.

When to reach for it

Perl makes sense when text and regex are the central problem, when integrating with an existing Perl codebase (cPanel modules, Bugzilla extensions, Debian packaging), or when a single-file script needs to run on any Unix host without installing a runtime. For new web services, data science work, or anything requiring a large hiring pipeline, other languages are the more defensible choice.