What does `ls --author` mean?

What exactly means

ls --author

It really returns writer of a file or owner? How to set author for a file? I have to implement this part (ls --author), so need to know what exactly it is.

The Ubuntu manual page for "ls" neither explains what the "author" is and it also does not mention that the option only applies to long format. From a GNU/Hurd man page:

--author List each file's author when producing long format directory listings. In GNU/Hurd, file authors can differ from their owners, but in other operating systems the two are the same.

Example:

ls -l --author
total 0
lrwxrwxrwx 1 rinzwind rinzwind rinzwind 20 2011-06-18 19:33 Desktop

will shows 3 names instead of 2 (owner, group, author).

I found some good information on this on an old mail archive for gnu from 2002 but in Ubuntu it is the same as the user name.

If you need to set 'author' the idea is you create a man page for your function and add an author tag in the man page. Unless you use something other than Ubuntu and actually can set this.

On Ubuntu (and apparently any GNU/Linux) "author" is the same as owner.

See the info page (not the manpage) for coreutils/ls (info ls), or http://lists.centos.org/pipermail/centos/2006-March/019813.html.

Digression follows.

I have to implement this part(ls --author)

For what? Sounds like homework. I don't have a problem helping someone with homework, but I was a little bummed to find the answer after about 30 seconds of searching the web.

Maybe a "homework" tag on askubuntu.com would be useful, just for full disclosure.