what is the difference between Linux and Unix "in general" and "command-line"?

Question

if anyone can Summarized the difference between Linux and Unix in general and in command-line in particular

Answer 1

• Licences differ from GPL (Linux) to BSD (*BSD variants) to some other (whatever licences Solaris, HP-UX etc use)

• Kernel differs.

• System libraries differs; Linux distributions tend to use GNU userland, BSD, Solaris has their own. In my opinion for example FreeBSD feels much more like a finished product with more comprehensive and up-to-date documentation and system tools written for it, whereas Linux distributions are more like a puzzle where every piece is fetched from a different source. Linux works fine and is a nice system, though. :-)

• Package management differs, but that can be said between Linux distributions, too.

Other than that they are pretty much the same. Apache, MySQL, and all the other common software can be run on all of them.

Answer 2

UNIX specifically means compliant with the UNIX98 standard, which Linux isn't. In practice it doesn't matter very much these days; it did when there were dozens of different Unixes in common usage and people worried about compatibility.

Of course these days a program that runs on Red Hat might not run on Debian; have we really made progress?

Answer 3

"UNIX" is actually a copyright which I've sort of lost track of; but I believe is currently owned by SCO? They attempted to sue "Linux" (somewhat impossible to find a particular target there) and lost in a big time flame-war which was pretty much the last-gasp for SCO. Don't know that "UNIX" exists any longer except as a legal vagary.

The name was originally a joke. Thompson and Richie were playing around with an operating system for a PDP-11 at Bell Labs while the parent company was struggling to develop a multi-machine OS called "MULTICS". The powers-that-be did not realize that they had something good; so when asked by the developers if it was OK to share, they said "yes." BSD came from that part of the OS that was shared to UC Berkely (Berkely Software Distribution) before ATT realized it was hot and clamped down. Linux came much later when Linus Torvalds (may his name long be remembered) wrote a UNIX-like kernel in imitation of the ATT System V kernel. ALL of the Linux distros share their roots in Linus's kernel. BSD does not. BSD forked off from ATT many years earlier.

The differences (which still presist) are legal/political/philosophical. There are MANY discussions of the differences outside of StackExchange. They come from different starting points. Most (if not all) of the significant differences occur in core. The general OpenSource world is somewhat agnostic (you can run MariaDB/Apache/PHP on any of them).

Personally, I use FreeBSD. Have done for almost 15 years after BSDi failed.