# Regular Expressions (Perl-Compatible)

- Introduction
- Installing/Configuring
  - Requirements
  - Installation
  - Runtime Configuration
  - Resource Types
- Predefined Constants
- Examples
- PCRE Patterns
  - PCRE regex syntax — Pattern Syntax
  - Possible modifiers in regex patterns — Pattern Modifiers
  - Differences From Perl — Perl Differences
  - Differences from POSIX regex
- PCRE Functions
  - preg_filter — Perform a regular expression search and replace
  - preg_grep — Return array entries that match the pattern
  - preg_last_error_msg — Returns the error message of the last PCRE regex execution
  - preg_last_error — Returns the error code of the last PCRE regex execution
  - preg_match_all — Perform a global regular expression match
  - preg_match — Perform a regular expression match
  - preg_quote — Quote regular expression characters
  - preg_replace_callback_array — Perform a regular expression search and replace using callbacks
  - preg_replace_callback — Perform a regular expression search and replace using a callback
  - preg_replace — Perform a regular expression search and replace
  - preg_split — Split string by a regular expression