How to Run Perl in Visual Studio Code (VS Code)

Difficulty: Beginner (with some Intermediate tips)

Tags: perl, vscode, terminal, tasks, debugging, cpan, windows, macos, linux

Overview (what “running Perl in VS Code” really means)

Visual Studio Code is an editor, not a Perl runtime. To “run Perl in VS Code”, you install a Perl interpreter on your machine (or in WSL/Docker/remote server), then you use VS Code to execute a command like perl your_script.pl. You can run that command in the integrated terminal, or you can configure VS Code Tasks so running/linting/testing becomes a repeatable one-click or one-keystroke action.

A good production-friendly workflow usually includes:

• Perl installed and discoverable on PATH (or referenced by an absolute path).
• A Perl extension for syntax highlighting, navigation, and optional linting.
• VS Code Tasks for: run, syntax-check, and tests.
• A dependency strategy (core-only, or CPAN modules via a local install approach).

Step 1: Install Perl (and verify it works)

Windows: Many developers use Strawberry Perl because it behaves like a full Perl distribution and is friendly to CPAN module installs. During install, ensure Perl is added to your PATH.

macOS: Some macOS systems include a system Perl, but it may be older and Apple has historically discouraged relying on system language runtimes for development. Consider installing your own Perl (via a package manager or a Perl version manager) if you need a consistent modern version.

Linux: Perl is often installed by default. If not, install it via your distro package manager.

Verification (in any terminal):

perl -v

Common gotcha: If perl -v works in your normal terminal but fails in VS Code’s integrated terminal, that’s usually a PATH/environment issue. VS Code inherits environment variables from how it was launched (especially on macOS). In that case, run VS Code from a terminal, or adjust your shell/profile settings so PATH is initialized for login shells.

Step 2: Install a Perl extension in VS Code (recommended)

You can run Perl without any extension, but an extension makes VS Code feel like an IDE. Look for features like:

• Syntax highlighting and bracket matching
• Symbol navigation and “go to definition”
• Linting (often by calling perl -c or tools like perlcritic)
• Optional debugging support (varies by platform and adapter)

Even if you keep it minimal, having a syntax checker wired into your workflow (Task or extension) is a big productivity win.

Step 3: Run Perl using the integrated terminal (fastest and most universal)

This is the simplest approach and mirrors what you do on servers and CI systems.

1. Open your project folder in VS Code.
2. Open the integrated terminal: Terminal → New Terminal.
3. Run your script:

perl script.pl
perl script.pl arg1 arg2
perl -c script.pl   # compile/syntax-check only; does not run

When to prefer the terminal approach: diagnosing PATH issues, testing module availability, copying exact commands into documentation, and matching production-like behavior.

Step 4: Configure VS Code Tasks (repeatable run/lint/test)

Tasks let you standardize how scripts are executed. This is especially valuable for teams and production knowledge bases because it documents the exact command.

Create a file at .vscode/tasks.json in your project. Example (shown with HTML entities so it displays correctly in a web page):

{
  "version": "2.0.0",
  "tasks": [
    {
      "label": "Perl: Run current file",
      "type": "shell",
      "command": "perl",
      "args": [
        "${file}"
      ],
      "options": {
        "cwd": "${workspaceFolder}"
      },
      "group": {
        "kind": "build",
        "isDefault": true
      },
      "problemMatcher": []
    },
    {
      "label": "Perl: Syntax check current file",
      "type": "shell",
      "command": "perl",
      "args": [
        "-c",
        "${file}"
      ],
      "options": {
        "cwd": "${workspaceFolder}"
      },
      "problemMatcher": []
    },
    {
      "label": "Perl: Run tests (prove)",
      "type": "shell",
      "command": "prove",
      "args": [
        "-lr",
        "t"
      ],
      "options": {
        "cwd": "${workspaceFolder}"
      },
      "problemMatcher": []
    }
  ]
}

Run Tasks via Terminal → Run Task… (or bind a keyboard shortcut). For many Perl projects, the “run current file” and “syntax check current file” tasks cover 80% of day-to-day usage.

Step 5: Debugging Perl from VS Code (practical options)

Perl debugging in VS Code depends on the available debug adapter and your platform. In practice, there are three reliable approaches:

• Use the built-in Perl debugger in the terminal: universal, always available.
• Use logging and data dumps: often fastest for scripts and ops automation.
• Use a VS Code debugging extension: can be great, but verify compatibility with your Perl version and OS and document the setup for your team.

Built-in terminal debugger:

perl -d your_script.pl

Common debugger commands include n (next), s (step), c (continue), and p EXPR (print expression).

Runnable Perl examples (with expected output)

Example 1: A simple script with command-line arguments

Create hello.pl:

use strict;
use warnings;
use feature 'say';

my $name = shift(@ARGV) // 'World';

say 'Hello, ' . $name . '!';
say '2 + 3 = ' . (2 + 3);

Run:

perl hello.pl Alice

Expected output:

Hello, Alice!
2 + 3 = 5

Example 2: Read STDIN and summarize text (common real-world pattern)

Create count_text.pl:

use strict;
use warnings;
use feature 'say';

my ($lines, $words) = (0, 0);

while (my $line = <STDIN>) {
  $lines++;
  my @w = $line =~ /\S+/g;
  $words += scalar @w;
}

say 'lines=' . $lines;
say 'words=' . $words;

Run with piped input:

printf 'one two\nthree\n' | perl count_text.pl

Expected output:

lines=2
words=3

Example 3: JSON processing using core JSON::PP (no external CPAN needed)

Create json_demo.pl:

use strict;
use warnings;
use feature 'say';
use JSON::PP qw(encode_json decode_json);

my $data = {
  project => 'vscode-perl',
  ok      => JSON::PP::true,
  nums    => [1, 2, 3],
};

my $json = encode_json($data);
my $roundtrip = decode_json($json);

say $json;
say 'project=' . $roundtrip->{project};

Run:

perl json_demo.pl

Expected output:

{"project":"vscode-perl","ok":true,"nums":[1,2,3]}
project=vscode-perl

Best practices (production-friendly)

• Always use strict and warnings: use strict; use warnings; catches many mistakes early.
• Use syntax-checking often: a Task for perl -c is fast and prevents many runtime surprises.
• Organize projects predictably: scripts in bin/, modules in lib/, tests in t/. Run scripts with perl -Ilib when using local modules.
• Be explicit about working directory: Tasks can set cwd to ${workspaceFolder} so relative paths behave consistently.
• Make dependencies reproducible: if you use CPAN modules, document install steps (and consider per-project dependency tools).
• Handle encodings intentionally: production scripts often break on encoding differences; decide on UTF-8 (or another encoding) and apply it consistently.

Common pitfalls (and fixes)

• perl not found: install Perl, restart terminals, and ensure PATH is correct. On macOS, launching VS Code from the Dock can mean it doesn’t inherit your shell PATH.
• Wrong Perl selected: you might have multiple Perls (system Perl, Strawberry, WSL, perlbrew). Ensure VS Code is using the same interpreter you expect by running which perl (macOS/Linux) or where perl (Windows) in the integrated terminal.
• Missing modules: “Can’t locate Foo/Bar.pm” usually means the module isn’t installed for that Perl, or @INC doesn’t include your project’s lib/. Fix by installing the module for the right Perl, or running with -Ilib.
• CRLF line endings on Unix: can break shebang execution and tooling. Use LF line endings for scripts that run on Unix-like systems.
• Tasks run in an unexpected folder: set cwd in your Task, and prefer workspace-relative paths.

Real-world usage in VS Code

• Automation/ops scripts: cron jobs, backups, log parsing, deploy helpers. VS Code Tasks make it easy to run the exact same command repeatedly.
• Data cleanup and ETL: process CSV/TSV, normalize fields, filter records, generate reports. Perl’s text handling shines here, and VS Code makes iteration fast.
• Testing culture: writing tests under t/ and running with prove -lr t gives you a maintainable workflow; add it as a Task.
• Remote development: VS Code Remote (SSH/WSL/Containers) lets you edit locally but run Perl in the environment that matches production (correct OS, correct modules).

Quick starter checklist

1. Confirm perl -v works in VS Code’s integrated terminal.
2. Add .vscode/tasks.json with “Run current file” and “Syntax check current file”.
3. Write scripts with use strict; use warnings;.
4. If you use CPAN modules, document how to install them for your chosen Perl.
5. When something fails, run the exact command in the terminal first; then codify it as a Task.