Title: Competency 3 Introduction
Course: UNIX Operating System I (13673) > Section: Competency Modules

The Linux Shells are more than command interpreters. Each has a programming language of its own that can be used to write shell programs for performing various tasks that cannot be performed by any existing command. A shell program, commonly known as a shell script, consists of shell commands to be executed by a shell and is stored in an ordinary Linux text file. The shell allows use of a read/write storage place, known as a shell variable, for users and programmers to use as a scratch pad for completing a task. The shell also contains program control flow commands that allow nonsequential execution of the commands in a shell script and repeated execution of a block of commands similar to programming languages like C++, Java, and Visual BASIC.