The Unix shell has been around longer than most of its users have been alive. It has survived so long because it's a power tool that allows people to do complex things with just a few keystrokes. More importantly, it helps them combine existing programs in new ways and automate repetitive tasks so that they don't have to type the same things over and over again.
filesystem
: filesystem used in "Files and Directories"creatures
: DNA data used in "Loops"finding
: data using in "Finding Things"molecules
: PDB files used in "Pipes and Filters"scripting
: files and directories used in "Shell Scripts"