Perl on Wikipedia

Regular Expressions on Wikipedia

Perl and Regular Expressions: A Match Made in Regex Heaven

If you’ve ever dipped your toes into the world of regular expressions (regex), you’ve probably encountered Perl.

And if you haven’t, well, you might just be missing out on one of the greatest love stories in programming history.

Perl and regex go together like peanut butter and jelly, Batman and Robin, or—dare I say—nerds and caffeine.

A Brief History of Perl and Regex

Perl, created by Larry Wall in 1987, was designed for text processing. One of its standout features? Built-in, powerful regex support. Unlike many languages that had to bolt regex capabilities on as an afterthought, Perl was practically born with regex in its DNA.

Before Perl, regex was clunky and mostly confined to Unix utilities like sed and awk.

But Perl took regex, gave it a comfy home, and let it flourish. As a result, modern regex owes much of its expressive power and widespread use to Perl’s influence.

How Perl Uses Regex

Perl makes working with regex seamless by integrating it deeply into its syntax.

Here are some of the ways regex shows up in Perl:

1. Pattern Matching with `=~`

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my $string = "Hello, World!";
if ($string =~ /World/) {
    print "Match found!\n";
}

In Perl, you can use the `=~` operator to apply a regex pattern to a string:

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my $string = "Hello, World!";
if ($string =~ /World/) {
    print "Match found!\n";
}

Here, /World/ is the regex pattern, and Perl checks if $string contains it.

2. Substitutions with s///

Need to replace text? Perl makes it easy with the s/// substitution operator:

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my $text = "I love Java!";
$text =~ s/Java/Perl/;
print "$text\n";  # Output: I love Perl!

Take that, Java! (Just kidding, we love all languages here.)

3. Global Matching with g Modifier

Want to replace all occurrences? Just add g:

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my $sentence = "Perl is great. Perl is fun.";
$sentence =~ s/Perl/Rust/g;
print "$sentence\n";  # Output: Rust is great. Rust is fun.

4. Extracting Data with Capturing Groups

Perl’s regex engine lets you capture parts of a match using parentheses:

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my $date = "2024-02-01";
if ($date =~ /(\d{4})-(\d{2})-(\d{2})/) {
    print "Year: $1, Month: $2, Day: $3\n";
}

Boom! Now you have individual variables for year, month, and day.

Perl’s Influence on Modern Regex

Perl’s regex engine was so powerful and flexible that many programming languages borrowed heavily from it.

Languages like Python, JavaScript, and even modern versions of grep and sed owe a huge debt to Perl’s regex innovations.

Perl introduced features like:

• Non-greedy quantifiers (*?, +?)
• Lookaheads and lookbehinds ((?=...), (?<=...))
• Named capturing groups ((?<name>...))
• Extended regex with /x for readability

Many of these features became standard across other languages.

Conclusion: Perl and Regex—A Love Story for the Ages

Perl didn’t just adopt regex—it revolutionized it.

If regex were a rock band, Perl would be the electric guitar.

If regex were a superhero, Perl would be its origin story. You get the idea.

Even if you’re not a Perl programmer, every time you use regex in another language, you’re benefiting from Perl’s legacy.

So the next time you’re crafting a complex regex pattern, take a moment to thank Larry…

Also see Perl in a Nutshell

CHeck out:
https://imgur.com/t/perl

Regex Cheat Sheet

https://brianbraatz.github.io/tags/perl/