On UNIX and UNIX-like systems, the shell is the section of the operating system that interprets text commands for the computer execute. It is a command-line interface which means that any commands have to be in text form only. The shell is just one layer above the operating system and hence is a very powerful tool that can be used to do things that would normally be difficult with a GUI. In the right hands, the shell can be used to do perform powerful tasks like modifying files and folders; conversely, in the wrong hands, it could be devastating for your system. The shell in Windows is the DOS prompt that is still available for die-hard command-line fans.