SUMMARY: Numeric username

From: Antonia Gomez <antonia_at_fib.upc.es>
Date: Fri, 06 Sep 1996 11:57:17 +0100

My original asking was:

> Do you think about only numeric username? Is posible to have the
> passwd file with numeric username? Are there any problem?



Thanks at :

Jorge Granjal
Alan Cox
Stephen Carpenter
Akihito 'ycos' Yakoshi"
David Pesticcio
Marc.Thoelen
Daniel Bowman
Scott Chaffin
Andrew Weston

The general answer is that is not recommend the using of numeric
username.
Some answers are:
"
The first character of a username must be an alpha character. I think
this is documented in the installation material (or ever adduser script)

The reasoning is that unix uses a number (the UID) for its operations
and the username is an 'alias' for the UID to make life easy for humans.
You can still use the UID number (instead of the username) for
operations (EG chown 0 filename will change the owner to "root" or
UID (User ID) 0). If you use a numeric username, how will these unix
utilities know that you are using the username and not the UID.

This also goes for groups and group ID (GID).Andrew Weston"
__________________________________________________________
"Because, any owner ship command work mistakes.
i.e.
        A command "chown 0 /etc/motd" mean "chown root /etc/motd"
    or username is all zero?

The unkown owner file in your disk via NFS, you can see that.
Akihito 'ycos' Yakoshi""

____________________________________________________________

"
We have been doing this for several years now without trouble. However
the
quota system on a Pre-V4.0 system interprets the username as a UID. The
workaround was to explicitly include the u-parameter, e.g. quota -u
950234.
Marc.Thoelen"
____________________________________________________________
 "It sort of works but we do not recommend using numeric usernames. One
problem
is that chown can take a username OR uid and if the username is numeric
will the
file ownership be set correctly?

Stephen."
____________________________________________________________
"programs like chown assume that a numeric username is the uid value.
You need to
start with a letter, the rest can be numbers.

Alan"
____________________________________________________________
"
We have been using numeric usernames on our Alpha 2100 for over a year
without major problems. DEC did have to rewrite their quota utilities
to handle the all numeric names and irc does not work properly, but,
other than user complaints, these are the biggest problems.

Originally, DEC said that a user name had to begin with a letter, but
when I pointed out that their documentation only specified
alphanumeric and that a number was, the last time I checked,
alphanumeric, they agreed to fix some problems.

We are currently runing Digital Unix 3.2C and I plan to run 4.0 within
the next month or so.

Although it is POSSIBLE to use all numeric usernames, I would, because
of the volume of complaints from our users (12,000+ students) avoid it
if at all possible.

Scott A. Chaffin"

Thanks at all.
Received on Fri Sep 06 1996 - 12:28:04 NZST

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