The POSIX shell, also known as the Portable Operating System Interface (POSIX) shell, is a standard for command-line shells in Unix-like operating systems. It is defined by the POSIX standard, which specifies a set of interface conventions and functions for operating systems to follow in order to ensure interoperability and portability of applications.
The POSIX shell is a command-line interpreter that allows users to enter commands to perform tasks on a Unix-like system. It includes a number of built-in commands for navigating the file system, running programs, and performing basic system tasks. It also supports variables, control structures, and other programming constructs that can be used to create shell scripts for automating tasks.
The POSIX shell is designed to be compatible with a wide range of Unix-like systems, including Linux, macOS, and other systems that follow the POSIX standard. Many Unix and Linux systems include a POSIX-compliant shell as the default shell, such as the Bourne shell (sh) or the Korn shell (ksh).
In summary, the POSIX shell is a standard for command-line shells in Unix-like operating systems that is designed to ensure interoperability and portability of applications. It is a command-line interpreter that provides a number of built-in commands and programming constructs for performing tasks and automating tasks on a Unix-like system.