You could do something like:

sort fileName.txt | uniq > newfile.txt

Because Linux is "sort-of-a-copy-of-Unix" (which is not), and Unix was written in C.

C was created to write Unix. Most portable operating systems or serious embedded devices are written in some incarnation of C and C++. Including MS-DOS and earlier copies of Window$ (which I am sure still uses it)

The one I use most often is:

ls -lt

This sorts the files by most recent date first.

UUCP is the abbriviation of Unix to Unix copy. It is worldwide email system called UUCP or Unix to Unix copy.This email system was developed for the operating system called Unix.

No, but Linux is based on Unix since Linux is a Unix clone.