A Shell Script is a text file containing a series of commands that are executed by a command-line interpreter, known as a shell. It automates tasks in operating systems like Linux and Unix, allowing users to run multiple commands in sequence without manual input. Shell scripts can simplify complex processes, making them easier to manage and execute. These scripts are often used for system administration, file manipulation, and program execution. They can include variables, loops, and conditional statements, enabling more advanced functionality. By using shell scripts, users can save time and reduce the risk of errors in repetitive tasks.