Jeff Vance writes:
>  Validating the username is trickier, but could be done if you can search
> the HPUID.PUB.SYS file (which I don't know how to do), or if you do a
> LISTUSER @.@;format=brief to a file and do a binary search on this file.
>
> If a few folks are interested I can write a script.

Or just use a Perl/iX (http://www.cccd.edu/~markb/perlix.html) script:

picard:/TSS/MARK$ cat checkuid
#!/usr/contrib/bin/perl
getpwnam($ARGV[0]) ? print "Valid user\n" : print "Bogus user\n";

picard:/TSS/MARK$ ./checkuid MANAGER.SYS
Valid user

picard:/TSS/MARK$ ./checkuid FOOBAR.SYS
Bogus user
--
Mark Bixby                      E-mail: [log in to unmask]
Coast Community College Dist.   Web: http://www.cccd.edu/~markb/
District Information Services   1370 Adams Ave, Costa Mesa, CA, USA 92626-5429
Technical Support               Voice: +1 714 438-4647
"You can tune a file system, but you can't tune a fish." - tunefs(1M)