All kinds of programs or updates that are currently used in Ubuntu are installed exclusively from the repositories. However, many users do not even know what it is and what its main purpose is.
What it is?
The repository is a special place from which the user of the Ubunty operating system can install all kinds of updates or programs. If you used to use the Mac and Windows operating systems, then you probably already got used to the fact that the software is one or several installation files that are provided to the user on certain media or can be downloaded via the Internet. For the Ubuntu operating system, this option of software distribution is also provided, but this applies more to specialized proprietary or proprietary programs.
The repository is the place where most of the Ubuntu software is contained, which is packaged in specialized .deb files containing the required libraries. Such files can often be found on the Internet or on any portable media, even on the CD from which the operating system itself is installed.
Repository as Ubuntu Universal Storage
However, seeing such files, many users may not even know what the repository is. This is a specialized storage server on which such files are located. In other words, repositories can be called a kind of application source, since users from their computers connect to them through the Network or the Internet using specialized utilities, after which they can see which packages are already on the computer and which can be installed. It is worth noting that the vast majority of utilities supports the simple search by keywords, and can also break packages into several groups by categories.
The use of the “program-repository” bundle is the ability to use a fairly simple, and at the same time, centralized installation or removal of various software, as well as for users, it is much easier to upload various updates. The newly installed operating system may already contain the required repositories, but at the same time no one forbids using third-party data storages either .
Ubuntu repositories contain a huge amount of various software, so often there is nothing difficult in finding the utility you are interested in. Of course, you can simply download a package of .deb files from the Internet or even try to compile the program yourself from the sources, but you should understand that this option is more time-consuming and does not always end up being effective.
How to search and install various programs?
Initially, using the Ubuntu repositories, you should proceed from the fact that there is a certain task that must be solved with the help of the utility, but you may not even know if it exists and what it is called. However, it is likely that you know analog programs that are used in other operating systems.
Using some kind of Internet search engine, you find the variants of the program you are interested in, for example, typing the name of a similar utility in Windows, but adding “for Ubuntu” to the query. In the predominant majority of cases, the search engine will give you several names of programs, while it is worth noting the fact that they can be represented in a fairly large number, but you can choose the most optimal one according to the reviews of those users who have already managed to use it. Almost every modern utility has its own page on the Internet where you can familiarize yourself with additional features or view screenshots.
Where to download the program?
After you decide on the name of the program you are interested in, you will need to start the Ubuntu application center, and then find it in the available list. Most likely, you will be able to find it and install it in a fairly short time. In addition, it is likely that the developers have their own repositories for iOS 7 or other operating systems. In most cases, in such repositories are the latest versions of the program you are interested in, so if you are interested in maximum productivity, then you should carefully examine the site and use the search.
Only if you were not able to find the right program using repositories for iOS 7 or other OSs, you should try other installation options. It often happens that those versions of the software that are in the repositories are outdated options, but in fact there are often situations where they are better integrated into Ubuntu, and in certain situations they are also more stable .
Sections
In Ubuntu, the best repositories are divided into four sections, which are called components and are intended to reflect the page both in the license and in the level of user support available. Packages are divided into components as follows:
- Main is completely free software supported by Canonical.
- Restricter is a proprietary software that includes mainly various device drivers. All utilities are also supported by Canonical.
- Universe is also free software, which is not officially supported by Canonical, but is controlled by the community of users of the operating system.
- Multiverse is proprietary software that does not have Canonical support.
Repository Types
There are also 5 main repositories:
- Release - packages that were released at the time of release.
- Release-security - packages in which there are some critical security updates.
- Release-updates - packages containing system updates, including also various more modern versions of software that were released after the official release.
- Release-backports - all kinds of backports that belong to new versions of certain software, which is available exclusively in unstable versions of the Ubuntu operating system.
- Partner is a repository containing various software from Canonical partner companies.
It is worth noting that, in addition to the official ones, there are also other repositories for iOS 8 and other operating systems. They can be created by the authors of certain utilities, as well as by people who simply decided to compile a complete package from the source, and then release it in the public domain for other users.
Adding via Launchpad
If you do not know how to add a repository, Launchpad will help you with this, providing the ability to create PPA repositories. These storages are relatively small packages in which the owner puts various source codes, and users receive a full deb-document at the output.
How to connect?
If a person does not find a utility of interest to him, he can independently figure out how to add a repository, and then load the necessary software into it. Indeed, quite often it happens that in the repositories of Ubuntu there are simply no various utilities that may be needed to solve certain problems. For this reason, there is a fairly large number of third-party repositories, when connected, you can access the necessary software. This can be done using the graphical interface or through the console.
Immediately it is worth noting the fact that in some repositories, in addition to the packages that you need, there can also be all kinds of experimental assemblies of various software, including also kernels that contain Linux repositories. Since the version of such packages is in most cases higher than those that you use, the Update Manager may try to update the system on its own. It will do this through free repositories, which can damage your system. For this reason, in any case, you need to carefully read the descriptions of the connected storage, as well as the information that is in the "Update Manager".
Using graphical interface
In this case, repositories for iOS 8 and other operating systems are connected as follows:
- Ubuntu Application Center opens.
- Next, go to the "Edit" / "Application Sources" item.
- In the new window, select the "Other software" tab, and then click on the "Add" button.
- In the new window, fill in the field “ART String:”, click the “Add Source” button.
- Now the source is added and turned on, you can close the window.
Since you have connected a new software source, you will need to update the package information. In the predominant majority of cases, after connecting, a window appears in which the user is prompted to update this data. In the window you just need to click on the "Update" button.
After you have updated all the information about the packages, the "Application Sources" window will be closed, and most likely you will get an error that the application source is unsigned. However, you can install the utilities of interest to you, which are contained in the repository you have connected, using standard tools. To resolve an unsigned repository error, you should already understand the security system.
Using console
This option is the most optimal of all existing methods. It’s best to add a local repository or other types of storage using the console. This is done quite simply, because the storage is added with just one command, such as, for example: sudo apt-add-repository ppa: ripps818 / coreavc.
If necessary, you can also delete the repository through the console in the same way.
Protection system
Since in most cases repositories are located on the Internet, it is likely that attackers can replace the repository with their own, which contains various modified packages. Thus, by installing modified software on your computer, the user can put his system at real risk. However, many repositories provide protection against spoofing. This protection option is implemented by comparing the digital signatures of the client and the repository. In the event that the repository has a digital signature, a key is present on the user computer that is public for this repository.
In Ubuntu, the storages located on the installation disks are generally trusted. If there are several connected repositories on the user computer at the same time, it is trusted stores that are preferred.
How to add a key?
By connecting the storage, which is protected by a digital signature, you will need to download a specialized public key, which must be added to the system. Quite often, a package available for installation can be provided for downloading, which will completely register the repository key on its own. If you download the key directly from the repository site, then in this case you will be provided with a regular file with the extension .gpg, .key or some other. You can add this file to the system using the console command sudo apt-key add repo.key, but instead of .key, the repository key that you received is indicated.
Adding a key through the server
The best option is to add the key through a specialized server that is protected. Quite often, when it comes to a key, its alphanumeric identifier is given, which at first glance the user may be completely incomprehensible, but this is a unique name. Such keys are located on special servers, from where anyone can get them.