How to prevent users from renaming files while providing write permissions on Linux

Question

For some special purpose, I want to prevent non-root users of the Linux Server from changing the filenames. However, they can modify and write to the contents of the file. How to do this from command line.

Answer 1

as root:

> mkdir -m 0755 testdir
> touch testdir/testfile
> chmod 0666 testdir/testfile

as guest:

> echo test > testdir/testfile
> mv testdir/testfile testdir/foobar
mv: cannot move `testdir/testfile' to `testdir/foobar': Permission denied

Works for me.