INTRO

As a sysadmin, one of your key tasks is to install new software as required. You’ll also need to be very familiar with the layout of the standard directories in a Linux system.

You’ll be getting practice in both of these areas in today’s session.

YOUR TASKS TODAY

Install a new application from the online repositories
Become familiar with some of the standard directories
Look at the format and content of some configuration files.

If you’ve used a smartphone "app store " or “market”, then you’ll immediately understand the normal installation of Linux software from the standard repositories. As long as we know what the name or description of a package (=app) is, then we can search for it:

 apt search "midnight commander"

This will show a range of matching “packages”, and we can then install them with apt install command. So to install package mc (Midnight Commander) on Ubuntu:

 sudo apt install mc

(Unless you’re already logged in as the root user you need to use sudo before the installation commands - because an ordinary user is not permitted to install software that could impact a whole server).

Now that you have mc installed, start it by simply typing mc and pressing Enter.

This isn’t a “classic” Unix application, but once you get over the retro interface you should find navigation fairly easy, so go looking for these directories:

/root /home /sbin /etc /var/log

…and use the links in the Resources section below to begin to understand how these are used. You can also read the official manual on this hierarchy by typing man hier.

Most key configuration files are kept under /etc and subdirectories of that. These files, and the logs under /var/log are almost invariably simple text files. In the coming days you’ll be spending a lot of time with these - but for now simply use F3 to look into their contents.

Some interesting files to look at are: /etc/passwd, /etc/ssh/sshd_config and /var/log/auth.log

Use F3 again to exit from viewing a file.

F10 will exit mc, although you may need to use your mouse to select it.

(On an Apple Mac in Terminal, you may need to use ESC+3 to get F3 and ESC+0 for F10)

Now use apt search to search for and install some more packages: Try searching for “hangman”. You will probably find that an old text-based version is included in a package called bsdgames. Install and play a couple of rounds…

Posting your progress

Post your progress, comments and questions to the forum.

EXTENSION

Use mc to view /etc/apt/sources.list where the actual locations of the repositories are specified. Often these will be “mirror” sites that are closer to your server than the main Ubuntu servers.
Read Repositories - CommandLine for more of the gory details.

RESOURCES