Can a user change groups? Instead of [s]et [u]ser - [s]et [g]roup

[cliff bedore]

In article <995 at twg.bc.ca> bill at twg.bc.ca (Bill Irwin) writes:
>I'm wondering if there is a way for a user to temporarily change
>their group.  That is, register a user as a member of more than
>one group in the /etc/group file, then have one of the group id
>numbers set in /etc/passwd, so that they belong to their main
>group when they log in.  If they later want to access some files
>that are not owned by them, nor their group, but are of a group
>that they are also a member of - they would change their group,
>work with the files, then return to their original group.
>
>The concept is exactly the way the su facility works.  Could it
>be called "sg" for "set group"?
>-- 
>Bill Irwin    -       The Westrheim Group     -    Vancouver, BC, Canada
>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>uunet!van-bc!twg!bill     (604) 431-9600 (voice) |     Your Computer  
>bill at twg.bc.ca            (604) 430-4329 (fax)   |    Systems Partner

See newgrp.  It does exactly what you want.  We use it extensively to maintain
security on our systems.  

Cliff