Linux comes closest to mind.
Commands you use in a Unix based computer OS to achieve certain things. Similar to MS/DOS commands in Windows. Mostly used in computers running the Linux OS. unix command
The reason for the exec functions being same/similar is because the Mac OS has its roots in variants of the Unix kernel.
No difference, really. Unix is an OS (Operating System)
unix.
UNIX is a command-based OS. In contrast, Windows is a menu-based OS.
kernel is everything in unix os
Why do you believe this is necessary? What OS are you talking about?
LINUX and UNIX are vendor independent OS
Hewlett-Packard Unix. It is a series of computers that runs the Unix OS. Most people recognize the HP as a computer company in the acronym. This their version with the Unix OS.
Unix is a specification. Mac OS X is a certified implementation of Unix. This like asking "What is the difference between a turtle and a red-eared slider."
Yes.
It is a UNIX made.