Debian/Ubunt Package Installation from Default Repositories.

Before you Begin

Note: This is meant to be a building upon the previous posts with minimal repetition, the previous post has relevant information,

Your chosen distribution will have a default package depository in which the "apt" (or apt-get) will retrieve packages maintained by the fine folks who maintain your Linux distro. I am using Ubuntu Server 18.04 LTS to create this post, if your experience may vary with different versions and distributions. Also remember to update your package list and upgrade your existing packages: with the "sudo apt update" and "sudo apt upgrade" commands  Alsot note: This is meant to be a building upon the previous posts with minimal repetition, the previous post has relevant information,

Finding Packages Names

"apt list <argument>".

The argument can include full names or partial names with a * character at the beginning and/or end of the partial word.

To Install Packages

"sudo apt install <package name>"

To Remove Packages

'apt remove <package name>"

 

Note: I used Telnet simply as an example, I do not suggest using telnet outside of legacy situations or during the configuration process.  It is a rather insecure protocol and old protocol that should only be used when there are no other options or in a learning lab environment.

Updating Debian Based Linux Installs

The Package Management System

Applications and the operating system itself is broken down in to piece of software called packages. Packages can be installed, uninstalled, and updated independently of each other.  Packages are held in depositories.  Depository's must be configured by URL, although a there will be a default depository per-configured for your Distro's Make and Model. Th default depository maintained by Ubuntu developers with stock packages that they maintain, regardless of the organization or team that wrote the software. This ensures everything you install has been compiled and tested for your specific version of Linux.  Third party developers can and do maintain their own independent depositories, which can added or removed bu the user/administrator, Although that will be covered in a future post.

APT

For Ubuntu and most other Debian based distributions to install software updates the command you need to know is  "apt".  apt is a a command that streamlines the use of two other commands "apt-get" and "apt-cache" into a single and more user friendly command. This command uses a the Debian Package Management System. "apt" is a front end command for both  "apt-get" and "apt-cache" commands into a single more user friendly command.

General Usage Structure:

"sudo apt  [options] <commands/argument>" - as usual you can get more information via "apt --help" and "man apt"

Update Package lists.

"sudo apt update"  - This updates the package lists.  It downloads fresh package lists and compares it to the system's own list of installed packages. It does NOT download or install any actual updates!

"sudo apt upgrade" - downloads and installs new versions of installed packages. It does not install any new dependencies.

"sudo apt full-upgrada"  will upgrades to the new version of the packages and install new dependencies.

"sudo apt autoremove"  - Removes unused packages, freeing up storage space.

Getting information with apt. 

 "apt list" - lists all packages, probably will fill buffer.

"apt list --installed" - lists installed packages.

"apt show <package name>"  - shows information about specific package(s).  Can use * symbol to list multiple matching.

The Basic Linux Commands

The inspiration for starting the Linux-centric series of post is finding the follow image posted on r/Ubuntu by u/Tunliar 

This is most of the core commands to using the Bash to administrate a Linux system with the command line.

How ever great the --help and man files are, they are were written and updates by someone who knows much more about Linux than you and often omit key basic definitions of abbreviations , lack explanations of concepts, and have abrupt descriptions for the arguments requires for the command. I find the best way to understand CLI commands is to create a written lab journal in a composition book, that can be used to jog your memory date, weeks, or months from now.  A well configured server shouldn't need constant administration.  A great problem with technology, you will always remember that you did something, but not the specifics of how you did it.  Ron Popeil once said. "Set it and forget it", creating a journal is a great way to better memorize and create your ultimate offline documentation. 

Write an entry for each command written in your own words, .  Sit down at and spend the time to digest the command's --help and man outputs, practice using the command's options, and then write down in your own words how to use the options and create valid arguments to achieve tasks. When I say, in you own words, try to avoid copying the man or --help word for word,  list the options and define them using words and explain the arguments in a manner that you best understand and customized for your specific reading level.

Keep this journal near your workstation.