How many cron fields are there for specifying the time to execute a cron job?

CORRECT TEXT
If you need to view per-user disk space usage on a filesystem, the ______ command can provide that information if the kernel is built to support it.

What is a well-known service that binds port 25 and is it required on all hosts?

You’ve been reviewing your security checklist and one of the items calls for reviewing the
/etc/passwd file. You cat the file and notice that, while most users have an x in the second column, a few have a 14 character string in the second column. What
action, if any, should you take?

You want to change the aging information in the /etc/shadow file. What is the best utility to use to do this?

To increase system security, it is often desirable to run daemons for system services with nonroot user ids. Which one of the following services can be run as a
non-root user?

You’ve just rebooted your server. Users complain that the server is refusing secure connections.
Which of the following is most likely causing this problem?

The files /etc/hosts.allow, /etc/hosts.deny and /etc/nologin all exist on your computer and the sshd daemon is running. What will happen when users try to connect
with ssh?

This is the file /etc/named.boot from the computer named tellus with IP address 128.66.12.10.
directory/etc
secondarycompany.com128.66.12.company.com.hosts
secondary66.128.IN-ADDR.ARPA128.66.12.5128.66.rev
primary0.0.127.IN-ADDR.ARPAnamed.local
cachenamed.ca
From this file, you know that:

In what file do you change default shell variables for all users?