[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: problem with chmod

On Thu, 2 Apr 2009, Christofer C. Bell wrote:

On Thu, Apr 2, 2009 at 6:55 AM, Bret Busby <bret@busby.net> wrote:

I know that is how the syntax used to be, because I remember a person (on a
UNIX system) losing his account, when he accidentally entered
chmod .
, which changed his . file permissions to zero, and not even the sysadmin
could save his account, so he had to be issued with a new account.

While this isn't specific to your issue (as I feel other responses in this
thread have answered your question adequately), there is nothing a user can
do with chmod to his or her home directory that the root account can't
recover.  For your friend's account, the following could have been performed
to get him started:
# find /home/username -type d -exec chmod 711 {} \;
# find /home/username -type f -exec chmod 640 {} \;

While this may not have set up everything exactly as your friend would have
preferred it, it would have made his account accessible to him again.  He
could then add appropriate permissions to things he wanted to grant public
access to (for example a public_html directory).

What our understanding was at the time, and this is going back about 20-odd years, now, and just starting to learn about UNIX, was that what the student had done (we were then students at a technical college, named in some countries, a polytechnic), was that he, by using
chmod . <CR>
had set the permissions on the . file of his account, to 000, and, as such, had made the . file on his account, completely inaccessible to everyone, including the superuser, and, as the . file is the root of the account, he had effectively made his account, totally inaccessible to everyone, including the superuser.

From memory, it was on a SCO UNIX System V system, running on a LabTam
minicomputer (it was a comparatively small technical college). The technical college also had a PDP 11/44, but that ran RSTS/e and, on occasion, RTS (I think it was), and was connected to the network of technical colleges, and to the VAX11/750, running VAX VMS (for FORTRAN and COBOL programming). I think that the network porotocol; was DECnet.

Bret Busby
West Australia

"So once you do know what the question actually is,
 you'll know what the answer means."
- Deep Thought,
  Chapter 28 of Book 1 of
  "The Hitchhiker's Guide to the Galaxy:
  A Trilogy In Four Parts",
  written by Douglas Adams,
  published by Pan Books, 1992


Reply to: