Terms

shell prompt: It's the display when you open linux or unix-like terminal

Verbose mode: Verbose mode is an option available in many computer operating systems, including Microsoft Windows, Mac OS and Linux that provides additional details as to what the computer is doing and what drivers and software it is loading during startup. This level of detail can be very helpful for troubleshooting problems with hardware or software, if errors are occurring during startup or after the operating system has loaded. There are several ways to enable Verbose Mode. During startup, the screen may display which key(s) to press on the keyboard to enable Verbose Mode. Typically users would press the escape (Esc) key for Linux, Ctrl+V keys for Microsoft Windows, and Command-V keys for Mac OS.

POSIX: POSIX (Portable Operating System Interface) is a set of standard operating system interfaces based on the Unix operating system. The need for standardization arose because enterprises using computers wanted to be able to develop programs that could be moved among different manufacturer's computer systems without having to be recoded. Unix was selected as the basis for a standard system interface partly because it was "manufacturer-neutral." However, several major versions of Unix existed so there was a need to develop a common denominator system.