This is a list of the shellcommands of the most recent version of the Portable Operating System Interface (POSIX) –IEEE Std 1003.1-2024 which is part of the Single UNIX Specification (SUS). These commands are implemented in many shells on modern Unix, Unix-like and other operating systems. This list does not cover commands for all versions of Unix and Unix-like shells nor other versions of POSIX.
As is typical in the context of a POSIX system, the term file refers to an item of a file system which can be a regular file, a directory or several other more specialized types.
Columns:
Command
The text one enters to launch the command.
Category
Functional categorization.
Optionality
Indicates whether the command is mandatory or optional in order to achieve conformance. If the latter, then a code indicates the optional functionality group to which the command belongs.