Shells, Aliases, and Scripts
Every Unix user has a shell, which interprets commands; actually there are several, in particular the original Bourne shell (sh), and the C-shell (csh).
Aliases are a feature of csh, and its advanced successor tcsh, while scripts are possible in both shells. You get your choice, though the vast majority of shell scripts are for sh, since it's a simpler programming language.
Virtually everything in Unix is designed to be automated, customized, or used in an alias or a script. You never have to remember arcane Unix commands or switches for longer than it takes you to think up an alias for them.