Essentials of UNIX Administration with FreeBSD 12.1

In this module you are going to learn all about using the CLI environment of FreeBSD like a BOSS!

Learn to identify the default shell and current shell before changing the shell.

The command ls can be used to list contents of the file system. Learn how to use the command and options and create an alias for common options.

The cd command is used to navigate the file system. To understand the file system hierarchy we can read the man page, man 7 hier. This explains the purpose of each directory.

The find command is really important in locating files.

Read file with a multitude of commands: cat, cut, head and tail. We can write data with redirection using the > or >> operators.

You will love command piple-lines and learning how you can create bespoke behaviour for you own applications.

Let's make a quick and easy start in understanding how to add and remove software in FreeBSD

The starting point with software management in FreeBSD is the command pkg

Learn to use the which and whereis command

So what is with these editors, why more than one!

Vi is the default editor iin FreeBSD so a good starting point

If you are new to the command line than you may prefer nano, although still working at the CLI you have a menu in nano to make life more simple

Learning vim start with vimtutor

As a modal editor we have 3 modes to work in:

• normal

• insert

• ex

So what can vi improved or vim actually do?

Let's start to understand what we will cover when managing files.

You can download these slides as a learning resource as well as following the demonstrations

Here, we can learn the difference between moving and copying files

By reading the hard-link count of a directory we can work out really quickly how many subdirectories exist in that directory. We teach you how

We can use the ln command to create hard links ourselves but we are more likely to create soft links with ln -s

Soft link are separate files and point to the target location

A named pipe is a special file type use to marshal data between processes.

The slides introduce the file permissions and can be downloaded a a reference for the topic

Take a look at how we can manage file permissions in FreeBSD

The default permissions are controller through the current umask value of the shell

Using the command chmod we can set permissions of files

The execute permission is needed to work with directories but we can skip the read permission if we know the file we need.

Using chown we can change the user owner and chgrp to change the group owner

Users that can write to a directory can delete from the directory. Control this with the sticky bit

Control assignment of permissions via the SGID permission.

Similarly, we can use the SUID to control access to secure files

ACLs really add to your security being able to add more than a single user and group

Let's run through the slides so we know what we will be looking at and don't forget to download the PDF as part of your learning resources

Working with UFS filesystems we need to enable the acls option.

Let's start to introduce ACLs and how we can see they are set using ls and read them using the getfacl command. As a quick example we will also set an ACL with setfacl

The setfacl command can be used to create and modify ACLs

A default ACL can be set on directories. This default is then applied to all new files and directories created in the directory.

In this clip I introduce to you the topic of user management

These slides help signpost the topics that we look at and become a resource that you can download and keep.

The simplest way to create users in with the adduser interactive script

If you have many users to create then you will use pw useradd

Learn how to set and configure user defaults

We have a myriad of tools to manage users from chpass to finger

We look at how we pass encrypted and unencrypted passwords to the pw command and how to create your own simple C program to encrypt passwords

Having looked at users we now turn our attention to group management

As an alternative to su we can install sudo as a mechanism to raise privileges.

Learn what we cover in this module

Using the sysctl command we can learn more about the hardware

Using commands like uptime and top we can see the system load

Using the ps command we can manage the processes

The shutdown command can control users logins and well as rebooting the system