50.3. Who Will Own a New File?
you share files with other users, it's good to be
able to tell who will own each file. On many systems, this is even
more important because only the superuser can
change file ownership (Section 50.14, Section 50.15).
When you create a new file, it belongs to you.
When you append to a file with
>>file, the owner
doesn't change because Unix doesn't
have to create a new file.
When you rename a file with mv,
the ownership doesn't change.
Exception: if you use mv to move a file to another
filesystem, the moved file will belong to you, because to move across
filesystems, mv actually has to copy the file and
delete the original.
When you copy a file, the copy belongs to you because you created it
When you edit a file:
With an editor like vi (Section 17.2), the file keeps its original owner because a
new file is never created.
An editor like Emacs (Section 19.1), which makes a backup copy, can be different.
The backup copy could belong to you or to the original owner. If you
replace the edited file with its backup, the file's
ownership might have changed:
% emacs filea
...Edit a lot, then decide you don't want your changes...
% mv filea~ filea
If you aren't sure, use ls
-l (Section 50.2).
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