Complete Perl Programming Language book for modern system administrators

This comprehensive guide covers: - 22 chapters of practical Perl programming - Focus on system administration and automation - Modern Perl best practices and techniques - Real-world examples and production-ready code - 3 appendices with one-liners, gotchas, and resources The book targets experienced sysadmins, DevOps engineers, and automation specialists, demonstrating Perl's continued relevance in 2025 for text processing, system administration, and rapid development. 🤖 Generated with Claude Code Co-Authored-By: Claude <noreply@anthropic.com>
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+# Chapter 2: Getting Started - Modern Perl Setup
+
+> "A good workman never blames his tools, but a smart one makes sure they're sharp." - Anonymous SysAdmin
+
+Before we dive into Perl's syntax and philosophy, let's get your environment set up properly. If you're going to be a Perl programmer in 2025, you might as well do it right from the start. This chapter will save you hours of frustration and teach you how the pros manage their Perl installations.
+
+## The Perl That's Already There (And Why You Shouldn't Use It)
+
+Open a terminal on almost any Unix-like system and type:
+
+```bash
+perl -v
+```
+
+Congratulations! You probably have Perl installed. On macOS, Linux, BSD—it's there. This is both a blessing and a curse.
+
+The blessing: Perl is so useful for system tasks that OS vendors include it by default.
+
+The curse: That system Perl is there for the OS, not for you. It might be ancient (I'm looking at you, CentOS), it definitely has modules the system depends on, and updating it could break things in spectacular ways.
+
+**Golden Rule #1**: Never mess with system Perl. Leave it alone. It's not yours.
+
+## Enter Perlbrew: Your Personal Perl Paradise
+
+The solution? Install your own Perl. And the easiest way to do that is with Perlbrew—a tool that lets you install and manage multiple Perl versions without sudo, without conflicting with system Perl, and without tears.
+
+### Installing Perlbrew
+
+On macOS with Homebrew:
+```bash
+brew install perlbrew
+```
+
+On Linux/Unix:
+```bash
+curl -L https://install.perlbrew.pl | bash
+```
+
+Now add this to your shell configuration (`~/.bashrc`, `~/.zshrc`, etc.):
+```bash
+source ~/perl5/perlbrew/etc/bashrc
+```
+
+Restart your terminal or run:
+```bash
+exec $SHELL
+```
+
+### Your First Personal Perl
+
+Let's install a fresh, modern Perl:
+
+```bash
+# See available versions
+perlbrew available
+
+# Install the latest stable version (as of 2025, this would be 5.38+)
+perlbrew install perl-5.38.2
+
+# Or install with threading support (useful for some modules)
+perlbrew install perl-5.38.2 -Dusethreads
+
+# This will take a few minutes. Grab coffee. Perl is compiling.
+```
+
+Once installed:
+```bash
+# List your installed Perls
+perlbrew list
+
+# Switch to your new Perl
+perlbrew switch perl-5.38.2
+
+# Verify
+perl -v
+which perl  # Should show something like /home/you/perl5/perlbrew/perls/perl-5.38.2/bin/perl
+```
+
+Boom! You now have your own Perl that you can upgrade, modify, and experiment with without fear.
+
+## CPAN: Your New Best Friend
+
+CPAN (Comprehensive Perl Archive Network) is Perl's killer feature. It's a massive repository of reusable code that's been solving problems since 1995. But first, we need to configure it properly.
+
+### First-Time CPAN Setup
+
+Run:
+```bash
+cpan
+```
+
+The first time you run CPAN, it'll ask if you want automatic configuration. Say yes. It's smart enough to figure out your system.
+
+But we can do better. Let's install `cpanminus` (cpanm), a more modern, zero-configuration CPAN client:
+
+```bash
+# Install cpanminus
+cpan App::cpanminus
+
+# Or, if you prefer a one-liner:
+curl -L https://cpanmin.us | perl - App::cpanminus
+```
+
+Now you can install modules with:
+```bash
+cpanm Module::Name
+```
+
+No configuration dialogs, no interactive prompts, just installation. This is how we'll install modules throughout this book.
+
+### Essential Modern Perl Modules
+
+Let's install some modules that make Perl more pleasant in 2025:
+
+```bash
+# Modern::Perl - Enable modern Perl features with one line
+cpanm Modern::Perl
+
+# Perl::Tidy - Format your code consistently
+cpanm Perl::Tidy
+
+# Perl::Critic - Lint your code for best practices
+cpanm Perl::Critic
+
+# Data::Dumper - Inspect data structures (probably already installed)
+cpanm Data::Dumper
+
+# Try::Tiny - Better exception handling
+cpanm Try::Tiny
+
+# Path::Tiny - File path manipulation done right
+cpanm Path::Tiny
+
+# JSON::XS - Fast JSON parsing
+cpanm JSON::XS
+```
+
+## Your First Modern Perl Script
+
+Let's write a simple script using modern Perl features. Create a file called `hello_modern.pl`:
+
+```perl
+#!/usr/bin/env perl
+use Modern::Perl '2023';
+use feature 'signatures';
+no warnings 'experimental::signatures';
+
+sub greet($name = 'World') {
+    say "Hello, $name!";
+}
+
+greet();
+greet('Perl Hacker');
+
+# Let's use some modern features
+my @languages = qw(Perl Python Ruby Go Rust);
+say "Languages I respect: " . join(', ', @languages);
+
+# Postfix dereferencing (Perl 5.20+)
+my $hashref = { name => 'Larry', language => 'Perl' };
+say "Creator: " . $hashref->%*{'name'};
+
+# State variables (like static in C)
+sub counter {
+    state $count = 0;
+    return ++$count;
+}
+
+say "Counter: " . counter() for 1..3;
+```
+
+Run it:
+```bash
+perl hello_modern.pl
+```
+
+Notice what we did:
+- `use Modern::Perl '2023'` enables strict, warnings, and modern features
+- Subroutine signatures (no more `my ($arg1, $arg2) = @_`)
+- `say` instead of `print` (automatic newline)
+- State variables that maintain their value between calls
+- Postfix dereferencing for cleaner syntax
+
+## Setting Up Your Editor
+
+You can write Perl in any text editor, but some setup makes life easier. Here are configurations for popular editors:
+
+### VS Code
+Install the "Perl" extension by Gerald Richter. It provides:
+- Syntax highlighting
+- Code formatting via Perl::Tidy
+- Linting via Perl::Critic
+- Debugger support
+
+### Vim/Neovim
+Add to your `.vimrc`:
+```vim
+" Perl-specific settings
+autocmd FileType perl setlocal tabstop=4 shiftwidth=4 expandtab
+autocmd FileType perl setlocal cindent
+autocmd FileType perl setlocal cinkeys-=0#
+
+" Run perltidy on save (optional)
+autocmd BufWritePre *.pl :%!perltidy -q
+```
+
+### Emacs
+Emacs has excellent Perl support out of the box with `cperl-mode`:
+```elisp
+(defalias 'perl-mode 'cperl-mode)
+(setq cperl-indent-level 4)
+(setq cperl-close-paren-offset -4)
+```
+
+## Creating a Perl Project Structure
+
+Unlike some languages, Perl doesn't enforce a project structure. But here's a sensible layout for modern Perl projects:
+
+```
+my-perl-project/
+├── lib/           # Your modules
+├── script/        # Executable scripts
+├── t/             # Tests
+├── cpanfile       # CPAN dependencies
+├── .perltidyrc    # Code formatting config
+├── .perlcriticrc  # Linting config
+└── README.md
+```
+
+### Managing Dependencies with cpanfile
+
+Create a `cpanfile` to track your project's dependencies:
+
+```perl
+requires 'Modern::Perl', '1.20230701';
+requires 'Try::Tiny', '0.31';
+requires 'Path::Tiny', '0.144';
+
+on 'test' => sub {
+    requires 'Test::More', '1.302195';
+    requires 'Test::Exception', '0.43';
+};
+```
+
+Install dependencies:
+```bash
+cpanm --installdeps .
+```
+
+### Code Formatting with Perl::Tidy
+
+Create `.perltidyrc`:
+```
+# Indent style
+--indent-columns=4
+--continuation-indentation=4
+
+# Whitespace
+--add-whitespace
+--noblanks-before-blocks
+--blanks-before-subs
+
+# Line length
+--maximum-line-length=100
+
+# Braces
+--opening-brace-on-new-line
+--closing-brace-else-on-same-line
+```
+
+Format your code:
+```bash
+perltidy script.pl
+```
+
+### Linting with Perl::Critic
+
+Create `.perlcriticrc`:
+```
+severity = 3
+theme = core
+
+[TestingAndDebugging::RequireUseStrict]
+severity = 5
+
+[TestingAndDebugging::RequireUseWarnings]
+severity = 5
+```
+
+Check your code:
+```bash
+perlcritic script.pl
+```
+
+## The Perl Development Workflow
+
+Here's a typical workflow for developing Perl scripts in 2025:
+
+1. **Start with a shebang and Modern::Perl**
+   ```perl
+   #!/usr/bin/env perl
+   use Modern::Perl '2023';
+   ```
+
+2. **Write your code**
+
+3. **Format with perltidy**
+   ```bash
+   perltidy -b script.pl  # -b backs up original
+   ```
+
+4. **Check with perlcritic**
+   ```bash
+   perlcritic script.pl
+   ```
+
+5. **Test thoroughly** (we'll cover testing in a later chapter)
+
+6. **Document as you go** (POD - Plain Old Documentation)
+
+## Common Gotchas and Solutions
+
+### Problem: "Can't locate Module/Name.pm in @INC"
+**Solution**: You forgot to install the module. Run `cpanm Module::Name`
+
+### Problem: Script works on your machine but not on the server
+**Solution**: Check Perl versions (`perl -v`) and installed modules. Use `cpanfile` to track dependencies.
+
+### Problem: "Perl is too old" errors
+**Solution**: That's why we installed our own Perl with Perlbrew!
+
+### Problem: Different behavior on different systems
+**Solution**: Always use `#!/usr/bin/env perl`, not `#!/usr/bin/perl`. This uses the Perl in your PATH.
+
+## Your Toolkit Is Ready
+
+You now have:
+- A modern Perl installation you control
+- CPAN modules at your fingertips
+- An editor configured for Perl development
+- Tools for formatting and linting your code
+- A sensible project structure
+
+This is the foundation every serious Perl programmer needs. You're not writing CGI scripts in 1999; you're writing modern, maintainable Perl in 2025.
+
+In the next chapter, we'll dive into Perl's data types and variables. But unlike other tutorials, we'll focus on what makes Perl's approach unique and powerful for system administration and text processing tasks.
+
+---
+
+*Pro tip: Bookmark [metacpan.org](https://metacpan.org). It's the modern web interface to CPAN with better search, documentation, and dependency information. When you need a module for something, start there.*