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Linux POSIX character set


The Portable Operating System Interface (POSIX) is a standard that defines a set of APIs and command-line interfaces for software compatibility between Unix-like operating systems. One of the important components of POSIX is the character set. In Linux, the POSIX character set determines the characters that can be used in filenames, commands, and other system-related tasks. In this blog post, we will discuss the Linux POSIX character set and its components.

Components of POSIX character set

The POSIX character set consists of several components, each with a specific set of characters. Here are some of the most commonly used components in Linux:

[:alnum:]    Alphanumeric characters
[:alpha:]    Alphabetical characters
[:blank:]    Space and tab characters
[:cntrl:]    Control characters
[:digit:]    Numerical digits
[:graph:]    Printable and visible (excluding space) characters
[:lower:]    Lowercase characters
[:print:]    Printable characters (including whitespace)
[:punct:]    Punctuation characters
[:space:]    Whitespace characters
[:upper:]    Uppercase characters
[:xdigit:]   Hexadecimal characters