I am neither a lawyer or programmer and have a hard time understanding how programs like gnu and even the linux kernel are significantly different from AT&tT's unix code. I wonder how different the code has to be to called "rewritten from scratch" to satisfy copyright laws. I remember some of the court fights over supposed plagiarism that examine a song to the nth degree and I wonder how much difference can be in the orignal of say the "ls" command from the gnu version.
I have been wondering about this for years and just finally got around to asking. Thanks for your consideration.

The "ls" command's source code is released under an open source license.

The songs in question are not.

There is no set rule. There are court cases that one may look at to decide how good their claim may be.

Plenty of companies reverse engineer things but the process they use is designed to help avoid legal issue. They may have one team create a set of rules or requirements that may describe how the command ls works but has no references to that. Then a complete new team may try to write code that will do what the first team described.

Hi,

I can remember when IBM was too release AIX and all the trouble at that time. Heck, from a Personal computer standpoint I can remember all the issues and problems from Microsoft for IBM and DOS. That is why at the time we ended up with IBM-DOS. Also started earlier with IBM and Microsoft with CP/M and DOS. That was a major lose for CP/M when Gary Kildall of Digital Research, Inc was not available to talk about the sale. Always been some form of complaint when a new OS is introduced.

Now that we have Gnu/Linux with open source then everything is on the table for some one to look at.

Do any of you remember Apples complaints against Microsoft for the mouse and who designed it? Some major arguments between the two.

Looking at the history of computers and operating systems brings out some old memories for me.

Hope this helps.
Have fun & enjoy!

Or - remember the lawsuit in the late 80's between Stack Technologies and Microsoft? Microsoft literally stole Stack's data compression code and incorporated it into DOS. Stack proved their case and won the lawsuit, but so much time had passed that Microsoft was the big winner in terms of sales and market share, while Stack, I think, went out of business.

Anyone remember this https://en.wikipedia.org/wiki/SCO_Gr..._Machines_Corp. ?
(All about Linux ownership - sort of....)