F.4 Using Red Hat Linux

F.4.1 Why does Red Hat `adduser' put each user in his/her own group?

It's called the user group scheme, and it's described in the manual. What it basically does is allow you to use groups to allow multiple people to use a common set of files and edit them, transparently. It goes like this:

• You'd like to have a group of people work on a set of files in say, the ``/usr/lib/emacs/site-lisp'' directory. You trust a few people to mess around in there, but certainly not everyone.
• So you do ``chown -R root.emacs /usr/lib/emacs/site-lisp''. And you add the proper users to the group.
• To allow the users to actually create files in the directory you do ``chmod 775 /usr/lib/emacs/site-lisp''.
• This is fine, but when a user creates a new file it gets the group of the users default group (usually users).
• To prevent this you do `chmod 2775 /usr/lib/emacs/site-lisp' which causes everything in the directory to get created with the ``emacs'' group.
• This is fine, but the new file needs to be mode 664 for another user in the emacs group. To do this you make the default umask 002.
• Well, this all works good, except that if your default group is ``users'', every file you create in your home directory will be writable by everybody in ``users'' (usually everyone).
• To fix this, you make each user have a ``private group'' as their default group.

At this point, by making the default umask 002 and giving everyone a private default group, you can easily set up groups which users can take advantage of without doing any magic. Just create the group, add the users, and do the above chown and chmod on the group's directories.

F.4.2 Why doesn't the xmh shipped with Red Hat work properly?

We only ship xmh because it is part of the standard X11 distribution. xmh is basicaly shipped as-is from the X11 distribution, and is most likely broken. We've found that there are several better alternatives. If you want to use mh mail, install the mh RPM and the exmh RPM. exmh is a much better GUI mail reader than xmh.

F.4.3 I rebuilt my kernel, but I got vmlinux instead of vmlinuz. Why?

You need to do make boot instead of just make; this builds a compressed kernel and place it in /usr/src/linux/arch/i386/boot. You must copy it to /boot and run lilo yourself to use this one.

If you used make, you got a file called vmlinux. This is an uncompressed kernel image, and will NOT work! LILO will only boot a compressed kernel.

F.4.4 How do I make my own packages (RPMs)?

Simple. Read the RPM-HOWTO, available in the docs directory on any Red Hat Mirror.

F.4.5 I compiled a program, but I can't run it. What gives?

Lets say you do the following as root:

gcc -o hello hello.c
hello

You'll get ``hello: command not found''

Why?

By default, `.' is not in your path. You must run:

./hello

(dot, slash, h, e, l, l, o with no spaces)

For security reasons `.' should not be in your path.

F.4.6 Why doesn't xtexsh work?

xtexsh is based on older versions of Tcl/Tk than what we ship. Unfortunately, it has not been ported to the newer versions as of yet and it does not work at all.