Mastering Linux Security and Hardening

useradd on Debian/Ubuntu

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:

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

In this command:

• -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 ...