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Sah::Schema::pathname::unix - Filesystem path name on a Unix system


This document describes version 0.031 of Sah::Schema::pathname::unix (from Perl distribution Sah-SchemaBundle-Path), released on 2024-02-16.


     "summary"      => "Filesystem path name on a Unix system",
     "prefilters"   => ["Path::expand_tilde", "Path::strip_slashes"],
     "match"        => "\\A(?:/|/?(?:[^/\\0]{1,255})(?:/[^/\\0]{1,255})*)\\z",
     "x.completion" => ["filename"],

Base type: str

Used prefilters: Path::expand_tilde, Path::strip_slashes

Used completion: filename


Sample data and validation results against this schema

 ""  # INVALID

 "/"  # valid

 "foo/bar"  # valid

 "foo//bar"  # valid, becomes "foo/bar"

 "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"  # INVALID (Path element too long)

 "foo\0"  # INVALID (Contains null character)

Using with Data::Sah

To check data against this schema (requires Data::Sah):

 use Data::Sah qw(gen_validator);
 my $validator = gen_validator("pathname::unix*");
 say $validator->($data) ? "valid" : "INVALID!";

The above validator returns a boolean result (true if data is valid, false if otherwise). To return an error message string instead (empty string if data is valid, a non-empty error message otherwise):

 my $validator = gen_validator("pathname::unix", {return_type=>'str_errmsg'});
 my $errmsg = $validator->($data);
 # a sample valid data
 $data = "/";
 my $errmsg = $validator->($data); # => ""
 # a sample invalid data
 $data = "";
 my $errmsg = $validator->($data); # => "Must match regex pattern \\A(?:/|/?(?:[^/\\0]{1,255})(?:/[^/\\0]{1,255})*)\\z"

Often a schema has coercion rule or default value rules, so after validation the validated value will be different from the original. To return the validated (set-as-default, coerced, prefiltered) value:

 my $validator = gen_validator("pathname::unix", {return_type=>'str_errmsg+val'});
 my $res = $validator->($data); # [$errmsg, $validated_val]
 # a sample valid data
 $data = "/";
 my $res = $validator->($data); # => ["","/"]
 # a sample invalid data
 $data = "";
 my $res = $validator->($data); # => ["Must match regex pattern \\A(?:/|/?(?:[^/\\0]{1,255})(?:/[^/\\0]{1,255})*)\\z",""]

Data::Sah can also create validator that returns a hash of detailed error message. Data::Sah can even create validator that targets other language, like JavaScript, from the same schema. Other things Data::Sah can do: show source code for validator, generate a validator code with debug comments and/or log statements, generate human text from schema. See its documentation for more details.

Using with Params::Sah

To validate function parameters against this schema (requires Params::Sah):

 use Params::Sah qw(gen_validator);

 sub myfunc {
     my @args = @_;
     state $validator = gen_validator("pathname::unix*");

Using with Perinci::CmdLine::Lite

To specify schema in Rinci function metadata and use the metadata with Perinci::CmdLine (Perinci::CmdLine::Lite) to create a CLI:

 # in lib/
 our %SPEC;
 $SPEC{myfunc} = {
     v => 1.1,
     summary => 'Routine to do blah ...',
     args => {
         arg1 => {
             summary => 'The blah blah argument',
             schema => ['pathname::unix*'],
 sub myfunc {
     my %args = @_;

 # in
 use Perinci::CmdLine::Any;

 # in command-line
 % ./ --help
 myapp - Routine to do blah ...

 % ./ --version

 % ./ --arg1 ...

Using on the CLI with validate-with-sah

To validate some data on the CLI, you can use validate-with-sah utility. Specify the schema as the first argument (encoded in Perl syntax) and the data to validate as the second argument (encoded in Perl syntax):

 % validate-with-sah '"pathname::unix*"' '"data..."'

validate-with-sah has several options for, e.g. validating multiple data, showing the generated validator code (Perl/JavaScript/etc), or loading schema/data from file. See its manpage for more details.

Using with Type::Tiny

To create a type constraint and type library from a schema (requires Type::Tiny as well as Type::FromSah):

 package My::Types {
     use Type::Library -base;
     use Type::FromSah qw( sah2type );

         sah2type('pathname::unix*', name=>'PathnameUnix')

 use My::Types qw(PathnameUnix);


This is like the pathname schema but with extra checks relevant to the Unix, (e.g. a path element cannot be longer than 255 characters) and prefilters (e.g. multipile consecutive slashes // will be normalized into a single one /).


Please visit the project's homepage at


Source repository is at


perlancar <>


To contribute, you can send patches by email/via RT, or send pull requests on GitHub.

Most of the time, you don't need to build the distribution yourself. You can simply modify the code, then test via:

 % prove -l

If you want to build the distribution (e.g. to try to install it locally on your system), you can install Dist::Zilla, Dist::Zilla::PluginBundle::Author::PERLANCAR, Pod::Weaver::PluginBundle::Author::PERLANCAR, and sometimes one or two other Dist::Zilla- and/or Pod::Weaver plugins. Any additional steps required beyond that are considered a bug and can be reported to me.


This software is copyright (c) 2024, 2023, 2020, 2019, 2018, 2016 by perlancar <>.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.


Please report any bugs or feature requests on the bugtracker website

When submitting a bug or request, please include a test-file or a patch to an existing test-file that illustrates the bug or desired feature.