The useradd utility is there, but Debian and Ubuntu don't come with the handy preconfigured defaults as Red Hat and CentOS do. If you were to just do sudo useradd frank on a default Debian/Ubuntu machine, Frank would have no home directory and would be assigned the wrong default shell. So, to create a user account with useradd on a Debian or Ubuntu system, the command would look something like this:

sudo useradd -m -d /home/frank -s /bin/bash frank

In this command, we have the following:

• -m creates the home directory.
• -d specifies the home directory.
• -s specifies Frank's default shell. (Without the -s, Debian/Ubuntu would assign to Frank the /bin/sh shell.)

When you look at the home directories, you'll see that they're wide open, with execute and read privileges for everybody:

 donnie@packt:/home$ ls -l
 total 8
 drwxr-xr-x 3 donnie donnie 4096 Oct 2 00:23 donnie
 drwxr-xr-x 2 frank frank 4096 Oct 1 23:58 frank
 donnie@packt:/home$

As you can see, Frank and I can get into each other's stuff. (And no, I don't want Frank getting into my stuff.) Each user could change the permissions on his or her own directory, but how many of your users would know how to do that? So, let's fix that ourselves:

 cd /home
 sudo chmod 700 *

Let's see what we have now:

 donnie@packt:/home$ ls -l
 total 8
 drwx------ 3 donnie donnie 4096 Oct 2 00:23 donnie
 drwx------ 2 frank frank 4096 Oct 1 23:58 frank
 donnie@packt:/home$

That looks much better.

To change the default permissions setting for home directories, open /etc/login.defs for editing. Look for the following line:

UMASK 022

Change it to this:

UMASK 077

Now, new users' home directories will get locked down on creation, just as they do with Red Hat.