Introducing Regular Expressions (Michael Fitzgerald)（Z-Library）

【One-Line Pitch】 A hands-on, example-driven introduction to regular expressions for programmers who have never used them, teaching you to match, extract, and transform text across command-line tools and languages. Best for beginners who want practical fluency fast, not a reference for experts. 【Book Arc】 - **Opening (~0%–10%)**: Frames what regex is, why it belongs in a programmer's toolkit, and sets up the Unix/Linux tooling (Cygwin, BSD/Darwin) and practice files you'll need. - **Early (~10%–30%)**: Builds core matching skills through Regexpal/RegExr — string literals, digits, letters, word/non-word characters, whitespace, and the first quantifiers, using a phone-number example as the running exercise. - **Middle (~30%–50%)**: Moves into anchors and boundaries (`^`, `$`, `\b`, `\B`, `\A`, `\Z`), then applies them to real text by marking up a poem with HTML5 tags using sed and Perl. - **Late (~50%–80%)**: Covers the structural power tools — alternation, subpatterns, capturing/named/non-capturing/atomic groups, backreferences, and character classes including negated, union/difference, and POSIX classes. - **Ending (~80%–100%)**: Extends matching beyond ASCII into Unicode characters, octal escapes, and Unicode character properties, with appendices documenting tool-specific regex features. 【Key Takeaways】 - **Regex is a transferable skill, not a language feature** (Early): the same core syntax appears in Unix utilities and in Perl, Java, JavaScript, and C#, though the book stresses that dialects differ meaningfully. - **Character shorthands compress common patterns** (Early): `\d`, `\D`, `\w`, `\W`, `\s`, `\S` replace verbose character classes like `[0-9]` or `[a-zA-Z0-9]`, making expressions shorter and more readable. - **Quantifiers control repetition, and they're where beginners over-match** (Early): `?`, `+`, `*`, and `{m,n}` let you tune how many times something repeats; the phone-number example shows how a loose quantifier matches unintended digit groups. - **Anchors and boundaries are zero-width assertions** (Middle): `^`, `$`, `\b`, and `\B` match positions, not characters — a subtle but essential mental model for precise matching. - **Groups do double duty: structure and capture** (Late): parentheses cluster subpatterns for quantifiers and capture text for backreferences, while named, non-capturing, and atomic groups offer control over that behavior. - **Character classes are the workhorse for "any of these" matching** (Late): negated classes, union/difference, and POSIX classes give fine-grained control over what a single position accepts. - **Regex reaches beyond English text** (Ending): Unicode code points, octal escapes, and Unicode character properties let you match international and special characters, not just ASCII. - **Practice beats reading** (Early): the book repeatedly insists that regex only sticks if you run the examples yourself, and it points to a GitHub repo and downloadable example archive. 【Reading Tips】 - **Deep-read the early chapters and type every example** — the phone-number progression is the book's teaching spine; skimming it will cost you later. - **Skim the tool-installation and version-check passages** (Perl setup, Cygwin notes) unless you're actually configuring an environment; they're scaffolding, not concepts. - **Treat the sed/Perl markup chapter as a bridge, not a destination** — its value is showing regex in real pipelines; you don't need to master either tool here. - **Slow down on zero-width assertions and groups** — these are the two conceptual cliffs; re-read them with a live tester open. - **Keep a cheat sheet of shorthands and quantifiers** as you go; the book's strength is incremental syntax, and consolidation helps retention. 【Coverage Limits】 This guide is based on stratified excerpts covering the front matter, table of contents, and early-to-middle chapters; the later chapters on groups, character classes, and Unicode are summarized from headings and brief fragments, so specific examples there are not detailed. The excerpts do not cover the appendices' full technical tables or the book's complete exercise set.