• What is a regular expression?
  • A template for determining if a string has certain characteristics
  • $var =~ m/mushroom/
    • this is an expression
      • returns true if $var contains ‘mushroom’
      • false otherwise
• use re ‘strict’
  • can be used in perl 5.22+
  • can apply stricter rues than otherwise when compiling regex patterns
  • Finds things that may be legal but may not be what was intended

Operators

• m//
• s///
• qr//
• split

The basics

Simple word matching

• “Hello World” =~ /World/; # matches
• =~ is an operator to test if a string matches
• !~ negation matching operator

metacharacters

• { } [ ] ( ) ^ $ . | * + ? - \

• is a metacharacter only when \x is used

• } and ] are only metacharacters when paired with their corresponding opening character
• metacharacters can be matched as is by putting a backslash before it *

Other notes linking here:

Perl