unix
A Unix shell provides a text-based user interface for Unix-like operating systems. The shell is both an interactive command language and a scripting language, and it is used by the operating system to control the execution of the system using shell scripts.
There are many Unix shell programs available to developers, including Bash and Z shell.
tutorials and guides
> software for unix
> useful unix commands
> absolute and relative paths
> shell profile and rc files
> unix shell scripts
> editing files in vi
resources and references
YouTube: CrashCourse - “Keyboards & Command Line Interfaces: Crash Course Computer Science #22”