Resources

One line: Every claim in this library can be checked against a perldoc page — the list below says which page stands behind which chapter — and every idea in it has a sibling page in another language, linked from the lesson itself.

The primary sources

perldoc ships with perl, so all of these are also on your machine: perldoc perlrun, perldoc -f split, perldoc Encode.

One-liners (chapter 01)

• perlrun ↗ — every switch: -n, -p, -l, -a, -F, -i, -0, -C, -E.
• perlvar ↗ — $/, $\, $., $ARGV, $^I.
• B::Deparse ↗ — the module behind -MO=Deparse.

Unicode text (chapter 02)

• perlunitut ↗, then perlunifaq ↗, then perluniintro ↗ — the order the encodings library's man-pages lesson ↗ recommends.
• perlunicode ↗ — the reference, including the section called "The Unicode Bug".
• perlunicook ↗ — short recipes, each one a line or two you can paste.
• Encode ↗, the open ↗ pragma and the utf8 ↗ pragma.
• Unicode::Normalize ↗ and fc ↗.

Regex (chapter 03)

• perlretut ↗ to learn, perlre ↗ to look up.
• perlrecharclass ↗ — what \w, \d, \s match, and the /a and /aa modifiers.
• perlrebackslash ↗ — \R, \X, \b.
• perlop ↗ — "Regexp Quote-Like Operators": m//g in both contexts, s///r, s///e, tr///.
• feature ↗ — unicode_strings, and which use v5.xx turns it on.
• split ↗ and pos ↗.

Records and fields (chapter 04)

• chomp ↗, sort ↗, sprintf ↗.
• Unicode::Collate ↗ and Unicode::Collate::Locale ↗.
• Text::ParseWords ↗ and Scalar::Util ↗ (looks_like_number).
• Text::CSV ↗ — on CPAN, not in core; the parser the CSV lesson recommends.

The Unicode standards underneath

• UAX #29, Text Segmentation ↗ — what \X counts.
• UAX #15, Normalization Forms ↗ — NFC and NFD.
• UTS #10, the Collation Algorithm ↗ — what Unicode::Collate implements.

A book

• Perl One-Liners: 130 Programs That Get Things Done ↗, Peteris Krumins (No Starch Press, 2013). A catalogue of one-liners by task. Chapter 01 here is the mechanism under every one of them — read it first, and the book's programs stop being incantations.

Sibling libraries

Same house style, same answer-key contract:

• Encodings ↗ — bits, bytes, code points and UTF-8 from the bottom up. Several of its pages already measure Perl: A code point is not a character ↗ counts graphemes with Perl's \X, rune is an int32 ↗ has an Encode::decode column, The table has a version ↗ compares perl 5.42's Unicode tables with 5.34's, and "Handles Unicode" is four questions ↗ has a Perl row.
• Python ↗ — str and bytes. Its What ends a line ↗ compares Python's line splitting with Perl's $/ and \R.
• Java text ↗ — UTF-16, locales, and a split copied from Perl's.
• Ruby text ↗ — the language that kept Perl's -n, -p, -a, -F, -i, split and pack, and labels every string with an encoding where Perl keeps one flag.
• C ↗ — text as bytes and a convention, and ICU for everything beyond.
• Rust ↗ — its Strings chapter ↗ is the same subject with the encoding enforced by the type.

Tools worth having

• perldoc — the documentation above, offline. perldoc -f NAME for a function, perldoc -v '$/' for a variable.
• perl -MO=Deparse — what your switches compiled to. Chapter 01 uses it on every one.
• perl -CSDA -Mutf8 — the switches that make a one-liner decode its input, its arguments and its own source.
• Perl::Critic and Perl::Tidy, from CPAN — a linter and a formatter. Neither ships with perl.