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0.1.1 • Public • Published

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POSIX character classes for creating regular expressions.


Install with npm:

$ npm install --save posix-character-classes

Install with yarn:

$ yarn add posix-character-classes


var posix = require('posix-character-classes');
//=> 'A-Za-z'

POSIX Character classes

The POSIX standard supports the following classes or categories of charactersh (note that classes must be defined within brackets)[1]:

POSIX class Equivalent to Matches
[:alnum:] [A-Za-z0-9] digits, uppercase and lowercase letters
[:alpha:] [A-Za-z] upper- and lowercase letters
[:ascii:] [\x00-\x7F] ASCII characters
[:blank:] [ \t] space and TAB characters only
[:cntrl:] [\x00-\x1F\x7F] Control characters
[:digit:] [0-9] digits
[:graph:] [^[:cntrl:]] graphic characters (all characters which have graphic representation)
[:lower:] [a-z] lowercase letters
[:print:] [[:graph] ] graphic characters and space
[:punct:] [-!"#$%&'()*+,./:;<=>?@[]^_`{ | }~] all punctuation characters (all graphic characters except letters and digits)
[:space:] [ \t\n\r\f\v] all blank (whitespace) characters, including spaces, tabs, new lines, carriage returns, form feeds, and vertical tabs
[:upper:] [A-Z] uppercase letters
[:word:] [A-Za-z0-9_] word characters
[:xdigit:] [0-9A-Fa-f] hexadecimal digits


  • a[[:digit:]]b matches a0b, a1b, ..., a9b.
  • a[:digit:]b is invalid, character classes must be enclosed in brackets
  • [[:digit:]abc] matches any digit, as well as a, b, and c.
  • [abc[:digit:]] is the same as the previous, matching any digit, as well as a, b, and c
  • [^ABZ[:lower:]] matches any character except lowercase letters, A, B, and Z.



Pull requests and stars are always welcome. For bugs and feature requests, please create an issue.

Building docs

(This project's is generated by verb, please don't edit the readme directly. Any changes to the readme must be made in the readme template.)

To generate the readme, run the following command:

$ npm install -g verbose/verb#dev verb-generate-readme && verb

Running tests

Running and reviewing unit tests is a great way to get familiarized with a library and its API. You can install dependencies and run tests with the following command:

$ npm install && npm test


Jon Schlinkert


Copyright © 2017, Jon Schlinkert. Released under the MIT License.

This file was generated by verb-generate-readme, v0.5.0, on April 20, 2017.

  1. table and examples are based on the WikiBooks page for [Regular Expressions/POSIX Basic Regular Expressions](, which is available under the [Creative Commons Attribution-ShareAlike License](