Basic Perl Programming

Section 1: Perl in 2026

• What Perl is, what it suits and where it is still used
• Perl 5 versus Raku, and the 5.42 and 5.44 release cycle
• perldoc, the documentation at perldoc.perl.org and MetaCPAN
• Workshop: try one-liners with perl -e and perl -ne

Section 2: Lab: Installing Perl and Tools

• perlbrew on Linux and macOS, and Strawberry Perl or WSL on Windows
• VS Code with a Perl language extension
• cpanm and local::lib for installing modules
• Lab: Hello World with use v5.40 and say

Section 3: Lab: Syntax, Scalars and Operators

• Statements, comments, blocks, strict and warnings
• Numeric and string scalars, interpolation and quote operators
• Arithmetic, comparison, logical and concatenation operators, and precedence
• undef, defined-or (//) and chained comparisons
• Lab: a calculator that works on user input

Section 4: Lab: Arrays and Lists

• Declaring arrays, indexing and slices
• push, pop, shift, unshift and splice
• Scalar and list context
• sort, reverse, join and a first look at wantarray
• Lab: manage a list of names and rank scores

Section 5: Lab: Hashes

• Key-value pairs, exists and delete
• keys, values and multi-variable foreach loops
• Hash slices and counting frequencies
• Choosing between arrays and hashes for your data
• Lab: count the most frequent words in a text file

Section 6: Lab: Conditionals

• if, elsif, else and unless
• Postfix conditionals and the ternary operator
• Truth in Perl, and builtin true and false
• Alternatives to given/when using a hash of subroutines
• Lab: grade scores and validate input

Section 7: Lab: Loops

• while, until, for and foreach
• last, next, redo and loop labels
• Postfix loops and reading input line by line
• map and grep in place of repetitive loops
• Lab: transform and filter data with loops, map and grep

Section 8: Lab: Subroutines and Signatures

• Declaring and calling subroutines with signatures and defaults
• Returning scalars and lists
• Variable scope with my, our and state
• Anonymous subroutines and closures
• Lab: refactor the calculator into reusable functions

Section 9: Lab: Special Variables and Built-in Functions

• $_, @_, @ARGV, %ENV, $0 and $@
• String functions: length, substr, index, lc, uc and sprintf
• Numeric functions and List::Util
• Dates and times with localtime and Time::Piece
• Lab: a script that takes arguments and prints formatted output

Section 10: Lab: Regular Expression Basics

• Matching with m// and the =~ operator
• Character classes, quantifiers and anchors
• Capturing with parentheses, $1 and named captures
• Substituting with s/// and the i, g and x modifiers
• Lab: validate email and phone formats and split data apart

Section 11: Lab: Advanced Regex and Reporting

• Non-greedy matching, lookahead and lookbehind
• qr// and storing patterns for reuse
• Finding every match with /g in list context
• Formatting tabular reports with printf and sprintf
• Lab: extract data from web server logs and summarise it as a report

Section 12: Lab: References and Data Structures

• References to scalars, arrays, hashes and code
• Anonymous arrays and hashes
• Postfix dereferencing such as ->@* and ->%*
• Nested structures and inspecting them with Data::Dumper
• Lab: store staff records by department in a nested structure

Section 13: Lab: File I/O

• Three-argument open with lexical filehandles
• Reading, writing and appending, and :encoding(UTF-8) for Thai text
• File test operators and binary files
• Directories with opendir and File::Find
• Lab: a script that finds and renames files across a folder

Section 14: Lab: Error Handling and Debugging

• die, warn and readable error messages
• Modern try/catch compared with the old eval idiom
• Carp for errors raised from modules
• The debugger with perl -d
• Lab: make a file-reading script cope with missing files and bad data

Section 15: Lab: CSV, JSON and Admin Scripts

• Reading and writing CSV with Text::CSV
• JSON::PP and HTTP::Tiny for calling web APIs
• Command-line options with Getopt::Long
• Running system commands safely with system and qx
• Lab: a CSV-to-JSON converter with command-line options

Section 16: Lab: Modules and CPAN

• package, use, require and @INC
• Creating .pm files and exporting functions
• Finding modules on MetaCPAN and installing them with cpanm and a cpanfile
• Writing documentation in POD
• Lab: move the log-reading functions into a module with POD

Section 17: Lab: Object-oriented Perl

• Classic classes with package and bless
• Constructors, accessors and inheritance
• The new class, field, method and ADJUST syntax (experimental)
• Reading existing OOP code in older systems
• Lab: build account and transaction classes both ways

Section 18: Lab: Databases with DBI

• DBI and DBD::SQLite
• Placeholders to prevent SQL injection
• fetchrow_hashref, selectall_arrayref and transactions
• Connecting to MySQL, MariaDB or PostgreSQL
• Lab: store log analysis results in an SQLite database

Section 19: Lab: Web Applications with Mojolicious

• From old-style CGI to PSGI, Plack and Mojolicious
• Mojolicious::Lite: routes, parameters and templates
• Returning JSON for a web API
• Running with morbo during development, and deployment options
• Lab: a web page that shows the log report from the database

Section 20: Workshop: A Log Analysis Tool

• Workshop: combine the module, CSV, DBI and web page into one tool
• Write tests with Test::More and run them with prove
• Format code with perltidy and check it with Perl::Critic
• A checklist for modernising existing Perl scripts
• Present your work and plan next steps