| PERLCRITIC(1p) | User Contributed Perl Documentation | PERLCRITIC(1p) |
"perlcritic" - Command-line interface to critique Perl source.
perlcritic [-12345 | --brutal | --cruel | --harsh | --stern | --gentle]
[--severity number | name] [{-p | --profile} file | --noprofile]
[--top [ number ]] [--theme expression] [--include pattern]
[--exclude pattern] [{-s | --single-policy} pattern]
[--only | --noonly] [--profile-strictness {warn|fatal|quiet}]
[--force | --noforce] [--statistics] [--statistics-only]
[--count | -C] [--verbose {number | format}] [--allow-unsafe]
[--color | --nocolor] [--pager pager] [--quiet]
[--color-severity-highest color_specification]
[--color-severity-high color_specification]
[--color-severity-medium color_specification]
[--color-severity-low color_specification]
[--color-severity-lowest color_specification]
[--files-with-violations | -l]
[--files-without-violations | -L]
[--program-extensions file_name_extension]
{FILE | DIRECTORY | STDIN}
perlcritic --profile-proto
perlcritic { --list | --list-enabled | --list-themes | --doc pattern [...] }
perlcritic { --help | --options | --man | --version }
"perlcritic" is a Perl source code analyzer. It is the executable front-end to the Perl::Critic engine, which attempts to identify awkward, hard to read, error-prone, or unconventional constructs in your code. Most of the rules are based on Damian Conway's book Perl Best Practices. However, "perlcritic" is not limited to enforcing PBP, and it will even support rules that contradict Conway. All rules can easily be configured or disabled to your liking.
This documentation only covers how to drive this command. For all other information, such as API reference and alternative interfaces, please see the documentation for Perl::Critic itself.
Before getting into all the gory details, here are some basic usage examples to help get you started.
# Report only most severe violations (severity = 5)
perlcritic YourModule.pm
# Same as above, but read input from STDIN
perlcritic
# Recursively process all Perl files beneath directory
perlcritic /some/directory
# Report slightly less severe violations too (severity >= 4)
perlcritic -4 YourModule.pm
# Same as above, but using named severity level
perlcritic --stern YourModule.pm
# Report all violations, regardless of severity (severity >= 1)
perlcritic -1 YourModule.pm
# Same as above, but using named severity level
perlcritic --brutal YourModule.pm
# Report only violations of things from "Perl Best Practices"
perlcritic --theme pbp YourModule.pm
# Report top 20 most severe violations (severity >= 1)
perlcritic --top YourModule.pm
# Report additional violations of Policies that match m/variables/xms
perlcritic --include variables YourModule.pm
# Use defaults from somewhere other than ~/.perlcriticrc
perlcritic --profile project/specific/perlcriticrc YourModule.pm
The arguments are paths to the files you wish to analyze. You may specify multiple files. If an argument is a directory, "perlcritic" will analyze all Perl files below the directory. If no arguments are specified, then input is read from STDIN.
Option names can be abbreviated to uniqueness and can be stated with singe or double dashes, and option values can be separated from the option name by a space or '=' (as with Getopt::Long). Option names are also case-sensitive.
SEVERITY NAME ...is equivalent to... SEVERITY NUMBER
--------------------------------------------------------
--severity gentle --severity 5
--severity stern --severity 4
--severity harsh --severity 3
--severity cruel --severity 2
--severity brutal --severity 1
$> perlcritic --theme='bugs && pbp' MyModule.pm
Unless the "--severity" option is explicitly given, setting "--theme" silently causes the "--severity" to be set to 1. You can set the default value for this option in your .perlcriticrc file. See "POLICY THEMES" in Perl::Critic for more information about themes.
perlcritic --include=layout my_file.pl
This would cause "perlcritic" to apply all the "CodeLayout::*" policies even if they have a severity level that is less than the default level of 5, or have been disabled in your .perlcriticrc file. You can specify multiple "--include" options and you can use it in conjunction with the "--exclude" option. Note that "--exclude" takes precedence over "--include" when a Policy matches both patterns. You can set the default value for this option in your .perlcriticrc file.
perlcritic --exclude=strict my_file.pl
This would cause "perlcritic" to not apply the "RequireUseStrict" and "ProhibitNoStrict" Policies even though they have the highest severity level. You can specify multiple "--exclude" options and you can use it in conjunction with the "--include" option. Note that "--exclude" takes precedence over "--include" when a Policy matches both patterns. You can set the default value for this option in your .perlcriticrc file.
perlcritic --single-policy=nowarnings my_file.pl
This would cause "perlcritic" to apply just the "ProhibitNoWarnings" Policy, regardless of the severity level setting. No other Policies would be applied.
This is equivalent to what one might intend by...
perlcritic --exclude=. --include=nowarnings my_file.pl
... but this won't work because the "--exclude" option overrides the "--include" option.
The equivalent of this option can be accomplished by creating a custom profile containing only the desired policy and then running...
perlcritic --profile=customprofile --only my_file.pl
Verbosity Format Specification
----------- -------------------------------------------------------
1 "%f:%l:%c:%m\n",
2 "%f: (%l:%c) %m\n",
3 "%m at %f line %l\n",
4 "%m at line %l, column %c. %e. (Severity: %s)\n",
5 "%f: %m at line %l, column %c. %e. (Severity: %s)\n",
6 "%m at line %l, near '%r'. (Severity: %s)\n",
7 "%f: %m at line %l near '%r'. (Severity: %s)\n",
8 "[%p] %m at line %l, column %c. (Severity: %s)\n",
9 "[%p] %m at line %l, near '%r'. (Severity: %s)\n",
10 "%m at line %l, column %c.\n %p (Severity: %s)\n%d\n",
11 "%m at line %l, near '%r'.\n %p (Severity: %s)\n%d\n"
Formats are a combination of literal and escape characters similar to the way "sprintf" works. See String::Format for a full explanation of the formatting capabilities. Valid escape characters are:
Escape Meaning
------- ------------------------------------------------------------
%c Column number where the violation occurred
%d Full diagnostic discussion of the violation
%e Explanation of violation or page numbers in PBP
%F Just the name of the file where the violation occurred.
%f Path to the file where the violation occurred.
%l Line number where the violation occurred
%m Brief description of the violation
%P Full name of the Policy module that created the violation
%p Name of the Policy without the Perl::Critic::Policy:: prefix
%r The string of source code that caused the violation
%C The class of the PPI::Element that caused the violation
%s The severity level of the violation
The purpose of these formats is to provide some compatibility with text editors that have an interface for parsing certain kinds of input. See "EDITOR INTEGRATION" for more information about that.
Setting a pager turns off color by default. You will have to turn color on explicitly. If you want color, you'll probably also want to tell your pager to display raw characters. For "less" and "more", use the -R switch.
--program-extensions .pl
The matching is case-sensitive, and the option may be specified as many times as desired, e.g.
--program-extensions .pl --program-extensions .cgi
The above can also be done by quoting the file name extensions:
--program-extensions '.pl .cgi'
Files whose name ends in '.PL' will always be considered programs.
Most of the settings for Perl::Critic and each of the Policy modules can be controlled by a configuration file. The default configuration file is called .perlcriticrc. "perlcritic" will look for this file in the current directory first, and then in your home directory. Alternatively, you can set the "PERLCRITIC" environment variable to explicitly point to a different file in another location. If none of these files exist, and the "--profile" option is not given on the command-line, then all Policies will be loaded with their default configuration.
The format of the configuration file is a series of INI-style blocks that contain key-value pairs separated by "=". Comments should start with "#" and can be placed on a separate line or after the name-value pairs if you desire.
Default settings for perlcritic itself can be set before the first named block. For example, putting any or all of these at the top of your .perlcriticrc file will set the default value for the corresponding command-line argument.
severity = 3 #Integer or named level
only = 1 #Zero or One
force = 0 #Zero or One
verbose = 4 #Integer or format spec
top = 50 #A positive integer
theme = (pbp + security) * bugs #A theme expression
include = NamingConventions ClassHierarchies #Space-delimited list
exclude = Variables Modules::RequirePackage #Space-delimited list
The remainder of the configuration file is a series of blocks like this:
[Perl::Critic::Policy::Category::PolicyName]
severity = 1
set_themes = foo bar
add_themes = baz
arg1 = value1
arg2 = value2
"Perl::Critic::Policy::Category::PolicyName" is the full name of a module that implements the policy. The Policy modules distributed with Perl::Critic have been grouped into categories according to the table of contents in Damian Conway's book Perl Best Practices. For brevity, you can omit the 'Perl::Critic::Policy' part of the module name.
"severity" is the level of importance you wish to assign to the Policy. All Policy modules are defined with a default severity value ranging from 1 (least severe) to 5 (most severe). However, you may disagree with the default severity and choose to give it a higher or lower severity, based on your own coding philosophy. You can set the "severity" to an integer from 1 to 5, or use one of the equivalent names:
SEVERITY NAME ...is equivalent to... SEVERITY NUMBER
----------------------------------------------------
gentle 5
stern 4
harsh 3
cruel 2
brutal 1
"set_themes" sets the theme for the Policy and overrides its default theme. The argument is a string of one or more whitespace-delimited alphanumeric words. Themes are case-insensitive. See "POLICY THEMES" for more information.
"add_themes" appends to the default themes for this Policy. The argument is a string of one or more whitespace-delimited words. Themes are case- insensitive. See "POLICY THEMES" for more information.
The remaining key-value pairs are configuration parameters that will be passed into the constructor of that Policy. The constructors for most Policy modules do not support arguments, and those that do should have reasonable defaults. See the documentation on the appropriate Policy module for more details.
Instead of redefining the severity for a given Policy, you can completely disable a Policy by prepending a '-' to the name of the module in your configuration file. In this manner, the Policy will never be loaded, regardless of the "--severity" given on the command line.
A simple configuration might look like this:
#--------------------------------------------------------------
# I think these are really important, so always load them
[TestingAndDebugging::RequireUseStrict]
severity = 5
[TestingAndDebugging::RequireUseWarnings]
severity = 5
#--------------------------------------------------------------
# I think these are less important, so only load when asked
[Variables::ProhibitPackageVars]
severity = 2
[ControlStructures::ProhibitPostfixControls]
allow = if unless # My custom configuration
severity = cruel # Same as "severity = 2"
#--------------------------------------------------------------
# Give these policies a custom theme. I can activate just
# these policies by saying "perlcritic --theme 'larry || curly'"
[Modules::RequireFilenameMatchesPackage]
add_themes = larry
[TestingAndDebugging::RequireTestLabels]
add_themes = curly moe
#--------------------------------------------------------------
# I do not agree with these at all, so never load them
[-NamingConventions::Capitalization]
[-ValuesAndExpressions::ProhibitMagicNumbers]
#--------------------------------------------------------------
# For all other Policies, I accept the default severity,
# so no additional configuration is required for them.
Note that all policies included with the Perl::Critic distribution that have integer parameters accept underscores ("_") in their values, as with Perl numeric literals. For example,
[ValuesAndExpressions::RequireNumberSeparators]
min_value = 1_000
For additional configuration examples, see the perlcriticrc file that is included in this examples directory of this distribution.
Damian Conway's own Perl::Critic configuration is also included in this distribution as examples/perlcriticrc-conway.
A large number of Policy modules are distributed with Perl::Critic. They are described briefly in the companion document Perl::Critic::PolicySummary and in more detail in the individual modules themselves. Say "perlcritic --doc PATTERN" to see the perldoc for all Policy modules that match the regex "m/PATTERN/ixms"
There are a number of distributions of additional policies on CPAN. If Perl::Critic doesn't contain a policy that you want, some one may have already written it. See "SEE ALSO" in Perl::Critic for a list of some of these distributions.
Each Policy is defined with one or more "themes". Themes can be used to create arbitrary groups of Policies. They are intended to provide an alternative mechanism for selecting your preferred set of Policies. For example, you may wish disable a certain set of Policies when analyzing test programs. Conversely, you may wish to enable only a specific subset of Policies when analyzing modules.
The Policies that ship with Perl::Critic are have been divided into the following themes. This is just our attempt to provide some basic logical groupings. You are free to invent new themes that suit your needs.
THEME DESCRIPTION
------------------------------------------------------------------------
core All policies that ship with Perl::Critic
pbp Policies that come directly from "Perl Best Practices"
bugs Policies that that prevent or reveal bugs
certrec Policies that CERT recommends
certrule Policies that CERT considers rules
maintenance Policies that affect the long-term health of the code
cosmetic Policies that only have a superficial effect
complexity Policies that specifically relate to code complexity
security Policies that relate to security issues
tests Policies that are specific to test programs
Say "perlcritic --list" to get a listing of all available policies and the themes that are associated with each one. You can also change the theme for any Policy in your .perlcriticrc file. See the "CONFIGURATION" section for more information about that.
Using the "--theme" command-line option, you can create an arbitrarily complex rule that determines which Policies to apply. Precedence is the same as regular Perl code, and you can use parentheses to enforce precedence as well. Supported operators are:
Operator Altertative Example
-----------------------------------------------------------------
&& and 'pbp && core'
|| or 'pbp || (bugs && security)'
! not 'pbp && ! (portability || complexity)'
Theme names are case-insensitive. If the "--theme" is set to an empty string, then it evaluates as true all Policies.
Perl::Critic takes a hard-line approach to your code: either you comply or you don't. In the real world, it is not always practical (or even possible) to fully comply with coding standards. In such cases, it is wise to show that you are knowingly violating the standards and that you have a Damn Good Reason (DGR) for doing so.
To help with those situations, you can direct Perl::Critic to ignore certain lines or blocks of code by using annotations:
require 'LegacyLibaray1.pl'; ## no critic
require 'LegacyLibrary2.pl'; ## no critic
for my $element (@list) {
## no critic
$foo = ""; #Violates 'ProhibitEmptyQuotes'
$barf = bar() if $foo; #Violates 'ProhibitPostfixControls'
#Some more evil code...
## use critic
#Some good code...
do_something($_);
}
The "## no critic" annotations direct Perl::Critic to ignore the remaining lines of code until a "## use critic" annotation is found. If the "## no critic" annotation is on the same line as a code statement, then only that line of code is overlooked. To direct perlcritic to ignore the "## no critic" annotations, use the "--force" option.
A bare "## no critic" annotation disables all the active Policies. If you wish to disable only specific Policies, add a list of Policy names as arguments just as you would for the "no strict" or "no warnings" pragma. For example, this would disable the "ProhibitEmptyQuotes" and "ProhibitPostfixControls" policies until the end of the block or until the next "## use critic" annotation (whichever comes first):
## no critic (EmptyQuotes, PostfixControls);
# Now exempt from ValuesAndExpressions::ProhibitEmptyQuotes
$foo = "";
# Now exempt ControlStructures::ProhibitPostfixControls
$barf = bar() if $foo;
# Still subject to ValuesAndExpression::RequireNumberSeparators
$long_int = 10000000000;
Since the Policy names are matched against the "## no critic" arguments as regular expressions, you can abbreviate the Policy names or disable an entire family of Policies in one shot like this:
## no critic (NamingConventions)
# Now exempt from NamingConventions::Capitalization
my $camelHumpVar = 'foo';
# Now exempt from NamingConventions::Capitalization
sub camelHumpSub {}
The argument list must be enclosed in parentheses and must contain one or more comma-separated barewords (i.e. don't use quotes). The "## no critic" annotations can be nested, and Policies named by an inner annotation will be disabled along with those already disabled an outer annotation.
Some Policies like "Subroutines::ProhibitExcessComplexity" apply to an entire block of code. In those cases, "## no critic" must appear on the line where the violation is reported. For example:
sub complicated_function { ## no critic (ProhibitExcessComplexity)
# Your code here...
}
Some Policies like "Documentation::RequirePodSections" apply to the entire document, in which case violations are reported at line 1. But if the file requires a shebang line, it is impossible to put "## no critic" on the first line of the file. This is a known limitation and it will be addressed in a future release. As a workaround, you can disable the affected policies at the command-line or in your .perlcriticrc file. But beware that this will affect the analysis of all files.
Use this feature wisely. "## no critic" should be used in the smallest possible scope, or only on individual lines of code. And you should always be as specific as possible about which policies you want to disable (i.e. never use a bare "## no critic"). If Perl::Critic complains about your code, try and find a compliant solution before resorting to this feature.
For ease-of-use, "perlcritic" can be integrated with your favorite text editor. The output-formatting capabilities of "perlcritic" are specifically intended for use with the "grep" or "compile" modes available in editors like "emacs" and "vim". In these modes, you can run an arbitrary command and the editor will parse the output into an interactive buffer that you can click on and jump to the relevant line of code.
The Perl::Critic team thanks everyone who has helped integrate Perl-Critic with their favorite editor. Your contributions in particular have made Perl- Critic a convenient and user-friendly tool for Perl developers of all stripes. We sincerely appreciate your hard work.
Joshua ben Jore has authored a minor-mode for emacs that allows you to run perlcritic on the current region or buffer. You can run it on demand, or configure it to run automatically when you save the buffer. The output appears in a hot-linked compiler buffer. The code and installation instructions can be found in the extras directory inside this distribution.
Scott Peshak has published perlchecker.vim, which is available at <http://www.vim.org/scripts/script.php?script_id=1731>.
Fritz Mehner recently added support for "perlcritic" to his fantastic gVIM plugin. In addition to providing a very Perlish IDE, Fritz's plugin enables one-click access to "perlcritic" and many other very useful utilities. And all is seamlessly integrated into the editor. See <http://lug.fh-swf.de/vim/vim-perl/screenshots-en.html> for complete details.
EPIC is an open source Perl IDE based on the Eclipse platform. Features include syntax highlighting, on-the-fly syntax check, content assist, code completion, perldoc support, source formatting with Perl::Tidy, code templates, a regular expression editing tool, and integration with the Perl debugger. Recent versions of EPIC also have built-in support for Perl::Critic. At least one Perl::Critic contributor swears by EPIC. Go to <http://e-p-i-c.sourceforge.net> for more information about EPIC.
Josh Clark has produced an excellent Perl-Critic plugin for BBEdit. See <http://globalmoxie.com/projects/bbedit-perl-critic/index.shtml> for download, installation, and usage instructions. Apple users rejoice!
Komodo is a proprietary IDE for Perl and several other dynamic languages. Starting in version 5.1.1, Komodo has built-in support for Perl-Critic, if you have the Perl::Critic and criticism modules installed. Free trial copies of Komodo can be obtained from the ActiveState website at <http://www.activestate.com>.
ActivePerl includes a very slick graphical interface for configuring and running Perl-Critic called "perlcritic-gui". A free community edition of ActivePerl can be obtained from the ActiveState website at <http://www.activestate.com>.
Visual Studio Code is a lightweight but powerful source code editor which runs on your desktop and is available for Windows, macOS and Linux.
The perlcritic extension can be found here: <https://marketplace.visualstudio.com/items?itemName=sfodje.perlcritic>
The steps to install the perlcritic extension:
Open a Perl file. Save it and perlcritic should fire. There is a triangle with an exclamation point on the status bar. Click it and it will open the issues that perlcritic has found.
If "perlcritic" has any errors itself, exits with status == 1. If there are no errors, but "perlcritic" finds Policy violations in your source code, exits with status == 2. If there were no errors and no violations were found, exits with status == 0.
The modular design of Perl::Critic is intended to facilitate the addition of new Policies. You'll need to have some understanding of PPI, but most Policy modules are pretty straightforward and only require about 20 lines of code. Please see the Perl::Critic::DEVELOPER file included in this distribution for a step-by-step demonstration of how to create new Policy modules.
If you develop any new Policy modules, feel free to send them to "<team@perlcritic.com>" and I'll be happy to consider putting them into the Perl::Critic distribution. Or if you would like to work on the Perl::Critic project directly, you can fork our repository at <https://github.com/Perl-Critic/Perl-Critic.git>.
The Perl::Critic team is also available for hire. If your organization has its own coding standards, we can create custom Policies to enforce your local guidelines. Or if your code base is prone to a particular defect pattern, we can design Policies that will help you catch those costly defects before they go into production. To discuss your needs with the Perl::Critic team, just contact "<team@perlcritic.com>".
You are encouraged to subscribe to the mailing list at <https://groups.google.com/d/forum/perl-critic>. At least one member of the development team is usually hanging around in <irc://irc.perl.org/#perlcritic> and you can follow Perl::Critic on Twitter, at <https://twitter.com/perlcritic>.
There are a number of distributions of additional Policies available. A few are listed here:
Perl::Critic::More
Perl::Critic::Bangs
Perl::Critic::Lax
Perl::Critic::StricterSubs
Perl::Critic::Swift
Perl::Critic::Tics
These distributions enable you to use Perl::Critic in your unit tests:
Test::Perl::Critic
Test::Perl::Critic::Progressive
There is also a distribution that will install all the Perl::Critic related modules known to the development team:
Task::Perl::Critic
Scrutinizing Perl code is hard for humans, let alone machines. If you find any bugs, particularly false-positives or false-negatives from a Perl::Critic::Policy, please submit them at <https://github.com/Perl-Critic/Perl-Critic/issues>. Thanks.
Adam Kennedy - For creating PPI, the heart and soul of Perl::Critic.
Damian Conway - For writing Perl Best Practices, finally :)
Chris Dolan - For contributing the best features and Policy modules.
Andy Lester - Wise sage and master of all-things-testing.
Elliot Shank - The self-proclaimed quality freak.
Giuseppe Maxia - For all the great ideas and positive encouragement.
and Sharon, my wife - For putting up with my all-night code sessions.
Thanks also to the Perl Foundation for providing a grant to support Chris Dolan's project to implement twenty PBP policies. <http://www.perlfoundation.org/april_1_2007_new_grant_awards>
Jeffrey Ryan Thalhammer <jeff@imaginative-software.com>
Copyright (c) 2005-2021 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.
| 2023-01-15 | perl v5.36.0 |