In order to legally be called a "Unix" system, operating systems must undergo a rigorous and expensive certification procedure. "Unix-like" refers to systems that have an architecture similar to Unix, but have not undergone certification.
No difference, really. Unix is an OS (Operating System)
what are similarities and differences between linux and unix?
Unix is an operating system, Java is a language.
Since there isn't a UNIX 95 or UNIX 98 per se, I think you are referring to Windows 95 or Windows 98..
Unix is the name of an Operating System (software) and Cisco is the name of a technology company.
unix is a multiuser operating system but widows is a single user operating system.
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."
Unix is a multi user, multi processing and multi tasking operating system
Neither one of them is a "language translator."
Linux is a Unix-like system. This means that it is inspired or influenced by Unix in some shape or form (Linux started off from Minix), but it is not directly derived from Unix. However, BSD is based on Unix, and macOS is indirectly Unix-based because of its mixed heritage with BSD.
They are both administrator accounts and have privileges to do anything on the system.
su substitute user.. and su is a unix command used to run the shell of another user without logging off..