login name length limit?

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5 total messages Started by Phil Tsao Tue, 21 Oct 1997 00:00

#841

Author: Phil Tsao
Date: Tue, 21 Oct 1997 00:00

11 lines
933 bytes

Hi,

Does anyone know what the length limit is for an Unix login
name in general?

Thank you.

--
Phil Tsao
e-mail: philt@technologist.com

Re: login name length limit?

#842

Author: Tom Fritz
Date: Tue, 21 Oct 1997 00:00

32 lines
2059 bytes

Phil Tsao (philt@technologist.com) wrote:
: Hi,

: Does anyone know what the length limit is for an Unix login
: name in general?

I would limit it to the normal 8 chars... more may cause problems with other
network services.  It is an old standard, but it never fails.

--tlf


: Thank you.

: --
: Phil Tsao
: e-mail: philt@technologist.com




--
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Re: login name length limit?

#843

Author: Eric Levenez
Date: Tue, 21 Oct 1997 00:00

19 lines
1806 bytes

abuse@netcom.com (Tom Fritz) wrote:
 > Phil Tsao (philt@technologist.com) wrote:
 > : Does anyone know what the length limit is for an Unix login
 > : name in general?
 > 
 > I would limit it to the normal 8 chars... more may cause problems with other
 > network services.  It is an old standard, but it never fails.

At the very beginning, it was 7 characters. Now all unix use 8 characters,
and the newer ones use 32 characters. See LOGNAME_MAX in <limits.h>.

-- 

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Re: login name length limit?

#844

Author: Jean-Guillaume Hamelin
Date: Fri, 24 Oct 1997 00:00

33 lines
1762 bytes

Phil Tsao wrote:
> 
> Hi,
> 
> Does anyone know what the length limit is for an Unix login
> name in general?
> 
> Thank you.
> 
> --
> Phil Tsao
> e-mail: philt@technologist.com



8 characters


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Re: login name length limit?

#845

Author: Richard L. Hamilton
Date: Sat, 25 Oct 1997 00:00

38 lines
2372 bytes

In article <abuseEIF2IF.3J7@netcom.com>,
	abuse@netcom.com (Tom Fritz) writes:
> Phil Tsao (philt@technologist.com) wrote:
>: Hi,
> 
>: Does anyone know what the length limit is for an Unix login
>: name in general?
> 
> I would limit it to the normal 8 chars... more may cause problems with other
> network services.  It is an old standard, but it never fails.

The minimum upper limit for the login name plus a terminating null
is _POSIX_LOGIN_NAME_MAX, which is 9 (i.e. 8 + the null terminator).

The maximum upper limit is sysconf(_SC_LOGIN_NAME_MAX), which on Solaris 2.5.1
is the same.

More traditionally, there is L_cuserid in /usr/include/stdio.h, which is
also typically 9 (including the null).

So a program should support 8 plus the terminator (or
sysconf(_SC_LOGIN_NAME_MAX), whichever is larger) but never require
that anything longer than 8 plus the terminator be entered.  No account
name longer than sysconf(_SC_LOGIN_NAME_MAX)-1 should be created, and
if you want your account names standard across a variety of Unix systems,
they should be limited to 8 characters.  And if you also want them standard
to older MVS systems (although for the POSIX requirements Open MVS may
have had to raise this to 8), you'd better limit your account names to
seven (7) characters.

-- 
ftp> get |fortune
377 I/O error: smart remark generator failed

Bogonics: the primary language inside the Beltway

mailto:rlhamil@mindwarp.smart.net  http://www.smart.net/~rlhamil

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