---
name: "Perl::Critic::Policy::RegularExpressions::RequireLineBoundaryMatching"
section: "3pm"
platform: "linux"
package: "perl-perl-critic"
version: "1.156-3"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/Perl::Critic::Policy::RegularExpressions::RequireLineBoundaryMatching"
---

# Perl::Critic::Policy::RegularExpressions::RequireLineBoundaryMatching(3pm)

Always use the "/m" modifier with regular expressions.

## NAME

Perl::Critic::Policy::RegularExpressions::RequireLineBoundaryMatching - Always use the "/m" modifier with regular expressions.

## AFFILIATION

This Policy is part of the core Perl::Critic distribution.

## DESCRIPTION

Folks coming from a `"sed"` or `"awk"` background tend to assume that `'$'` and `'^'` match the beginning and end of the line, rather than then beginning and end of the string.  Adding the '/m' flag to your regex makes it behave as most people expect it should.

```
    my $match = m{ ^ $pattern $ }x;  #not ok
    my $match = m{ ^ $pattern $ }xm; #ok
```

## CONFIGURATION

This Policy is not configurable except for the standard options.

## NOTES

For common regular expressions like e-mail addresses, phone numbers, dates, etc., have a look at the Regexp::Common module. Also, be cautions about slapping modifier flags onto existing regular expressions, as they can drastically alter their meaning.  See \<http://www.perlmonks.org/?node\_id=484238\> for an interesting discussion on the effects of blindly modifying regular expression flags.

## AUTHOR

Jeffrey Ryan Thalhammer  \<jeff@imaginative-software.com\>

## COPYRIGHT

Copyright (c) 2005-2011 Imaginative Software Systems. All rights reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.  The full text of this license can be found in the LICENSE file included with this module.