Know where startup and shutdown scripts reside.  What letter do startup
scripts all have in common?  Shutdown scripts?

Know how to write crontab commands and read them.

Know how to write lines that go into the syslog.conf file.

Know how to execute commands as the super user, and the format for lines
in the /etc/sudoers file

Know how to do useradd.  Remember the -k option to specify the location of
a "skeleton" directory other than the default one (which has what directory name?)

Similarly know how to use usermod and userdel.

Know how to kill processes and set their priority. Know how "nice" and "renice"
work.

Know the difference betwen UID and Effective UID, GID and Effective GID.

Know the chmod bits used to set UID and set GID, and also the sticky bit.

Know how to mount and unmount devices to the file system.