What is Shell and Sub Shell in Bash Script

Shell: Shell scripting is a powerful tool for automating tasks and simplifying the management of systems and applications. One important concept in shell scripting is the use of subshells, which allow you to execute commands within a separate shell environment.
Subshell: A subshell is a child shell that is spawned by the main shell (also known as the parent shell). It is a separate process with its own set of variables and command history, and it allows you to execute commands and perform operations within a separate environment.