Hello again.

No problemo.

Good.

Way to go.

No it's not - "equivalent to using the chgrp and chown commands".
If you suid/sgid an executable and run it as another user the "efective
user/group id" of the process will be that of the user/group owning the
file (not the one running it).

To illustrate, copy and paste the following in a file "get_sugid.c":
-----------------------------------------------------

#include <stdio.h>
/* We need this for getuid()/sgid() */
#include <unistd.h>
#include <sys/types.h>

int main(void){

        printf("Real UID\t= %d\n", getuid());
        printf("Effective UID\t= %d\n", geteuid());

        printf("Real GID\t= %d\n", getgid());
        printf("Effective GID\t= %d\n", getegid());

        return 0;

-------------------------------------------------------

And compile it using:
gcc get_sugid.c -o get_sugid

Now try out some differend user/group permission combinations and fire it up as
differend users (setting the first bit to "0" "2", "4" and "6")

There is a use for the "sgid" bit on non executable files also. As it is
used for (System V style) mandatory file locking as well. You will
probaply never have to use this (applications set it for you).

That is the way i go about it, as well. If some user needs accesse just
stick 'am in the group(s).

I always rip the rights for "others" of of any suid-binarys as well
(of couse "chgrp"ing those files to new groups and putting users that need
the functionality in those groups).

You can "find" suid files using:
find / -type f -perm +4000 -ls 2>/dev/null

man find

--
-Menno.