Operating System 4/4

In computing, a file system or filesystem is used to control how data is stored and retrieved. Without a file system, information placed in a storage medium would be one large body of data with no way to tell where one piece of information stops and the next begins.
By separating the data into pieces and giving each piece a name, the information is easily isolated and identified. Taking its name from the way paper-based information systems are named, each group of data is called a "file". The structure and logic rules used to manage the groups of information and their names is called a "file system".

There are many different kinds of file systems. Each one has different structure and logic, properties of speed, flexibility, security, size and more. Some file systems have been designed to be used for specific applications. For example, the ISO 9660 file system is designed specifically for optical discs.

File systems can be used on numerous different types of storage devices that use different kinds of media. The most common storage device in use today is a hard disk drive. Other kinds of media that are used include flash memory, magnetic tapes, and optical discs. In some cases, such as with tmpfs, the computer's main memory (random-access memory, RAM) is used to create a temporary file system for short-term use.

Some file systems are used on local data storage devices; others provide file access via a network protocol (for example, NFS, SMB, or 9P clients). Some file systems are "virtual", meaning that the supplied "files" (called virtual files) are computed on request (e.g. procfs) or are merely a mapping into a different file system used as a backing store. The file system manages access to both the content of files and the metadata about those files. It is responsible for arranging storage space; reliability, efficiency, and tuning with regard to the physical storage medium are important design considerations.







A path, the general form of the name of a file or directory, specifies a unique location in a file system. A path points to a file system location by following the directory tree hierarchy expressed in a string of characters in which path components, separated by a delimiting character, represent each directory. The delimiting character is most commonly the slash ("/"), the backslash character ("\"), or colon (":"), though some operating systems may use a different delimiter. Paths are used extensively in computer science to represent the directory/file relationships common in modern operating systems, and are essential in the construction of Uniform Resource Locators (URLs). Resources can be represented by either absolute or relative paths.

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Operating System 3/4

THERE ARE SEVERAL WAYS TO INSTALL SOFTWARE:

1. "Ubuntu Software Center"

It is the most simple and intuitive of all and as the new versions of Ubuntu are coming out, you will be implementing more functionalities. It is an authentic software store, with more than a thousand applications at your disposal.

To open it, click on the "Software Center" icon in the Launcher bar on the left or we can also click on the first launcher of the bar with the Ubuntu logo, open the Dash and write / Search: Software Center.

The application is divided into:

   1. In the upper tabs we have the following options "All applications", "Installed" and "History".
   2. On the left we have the applications divided into subcategories.
   3. In the Center the applications divided into "Most recent" and "Best rated".
   4. Top right we have the Search option.



Once the package or application is chosen, we can install it directly by clicking on the "Install" button. If we want to know more in detail what is the application, plugins to install and user ratings and comments, click on "More information".

Once the application is installed, the "Install" button will become "Uninstall", for the uninstallation of the application.


2. Synaptic Package Manager

Synaptic is an advanced system to install or remove applications from your system. The environment is graphic and very powerful. With Synaptic you have complete control of the packages (applications) installed in your system, its dependencies and from here you can select the different versions of the packages to be installed as needed.

From Ubuntu 12.04 is not installed by default and if you want to use it you have to install it from the Software Center, looking for "Synaptic".

To open Synaptic, click on the first launcher of the bar with the Ubuntu logo, to open the Dash and to type / search: Synaptic Package Manager.

This package manager will allow us to install, reinstall and remove packages in a very simple graphical way.

The Synaptic screen is divided into 4 sections.

The two most important are the list of categories (1) on the left side and the list of categories (3) on the right side.

Selecting a package from the list will show a description of the package (4).



To install a package you can select a category, right-click the desired package and select "mark to install" or double-click on the package name.

Tag this way all the packages you want to install on the system and press Apply to proceed with its installation. Synaptic will now download the necessary packages from the repositories on the internet or from the installation CD.

You can also use the Search button to find the packages you want to install.

By clicking on the search button, we can search for programs by name or description. Once located the program that we want to install we double click on it to install it. If you want to delete a program just right click on it and select delete or delete completely.

In order to apply the changes it is necessary to click on the Apply button.

The software installation system in Ubuntu is very powerful and versatile. Within the repositories the applications are organized into "packages". Each package has others that it depends on for its correct operation. Synaptic is responsible for solving these dependencies and installing the necessary packages for you. But not only that. In the packages of applications also indicate other packages that although they are not necessary for that the application that we want to install that they are useful if they are useful. These are the "recommended packages".

We can configure Synaptic to consider these "recommended" packages as if they were dependencies and so will automatically install them as well.

Start Synaptic and go to Settings -> Preferences, in the General tab check the box "Consider the recommended packages as if they were dependencies".


3. apt-get (apt) and aptitude commands in a terminal or console

Although we can install programs graphically as we have seen in the previous points, we can always use the terminal to install any program.

To many novice users this option may seem a bit more complicated and somewhat cryptic. Nothing is further from reality; When you get used to it, it's much more comfortable, easy, powerful and fast.

Note: Most of the application installation guides in this blog are explained with the use of the Terminal.

There are two commands to install text-mode programs: with apt-get (apt) or with aptitude.

Both programs are very similar, but we're going to focus on apt-get.

Update: As of Ubuntu 14.04 you can substitute "apt-get" for simply "apt".

The installation of software is an administrative task and therefore it is necessary to use the command "sudo", putting it before "apt-get" or "aptitude".

Usage: Open a terminal click on the first launcher of the bar with the Ubuntu logo, to open the Dash and to write / search: Terminal. It is also opened by pressing the key combination Ctrl + Alt + T

Note: packets with compound names carry a dash between words: eg: compizconfig-settings-manager

* Install packages:

Sudo apt-get install package_name


* Install several packages at a time leaving a blank space between them eg.

Sudo apt-get install gnome-do pidgin amsn


* Uninstall packages:

Sudo apt-get remove package_name


* Uninstall packages (including configuration files):

Sudo apt-get remove - purge package_name


* Update the list of available packages:

Sudo apt-get update


* Update the system with available package updates:

Sudo apt-get upgrade


* Get a list of command options:

Sudo apt-get help


After putting the command: We give the "Enter" and we put the password, that for security will not see when typing it, but YES it is being written and we give to the "Enter" again.

We will ask if we want to continue, we say YES and we give the "Enter".

4. Packages with .deb extension
Another way to install applications in the system is through the packages already ready to be installed and with .deb extension.
To install these packages just double click on the file in the Nautilus browser and will automatically launch the "Software Center" or gdebi application (if we have installed it), which will install the package and look for the dependencies of Other packages you may need for proper installation.

If you prefer, you can also install it using the command line, using the command dpkg:

Sudo dpkg -i package_name.deb


The same command can also be used to uninstall the package:

Sudo dpkg -r package_name


Convert .rpm files to .deb

Some Linux distributions, such as Red Hat and Mandriva, use .rpm packages, arranged differently than Debian and Ubuntu .deb packages. To install these packages, you must first convert them to .deb. This is done using the "alien" application. It can be installed via Synaptic or Terminal with apt-get.

Usage: Open a terminal (Applications → Accessories → Terminal) and execute the following command:

Sudo alien package_name.rpm


In this way the program creates a file with the name of the package, but with extension .deb, which can be installed following the explanation Packages with .deb extension

5. Files with .bin extension
Files with .bin extension are binary files. They do not contain a set of programs or libraries like packages, but they are the program itself.

Usually commercial programs are distributed under this system, which may or may not be free, but normally not free.

When you download a file of this type of internet and save it to your system, you will not have permission to run it. To give them:

The first thing you must do, therefore, is to give that file permission to run. To do this, right click on it and choose Properties. In the Permissions tab, you will see that the file has read and write permissions for the owner but not for execution. Check the box "allow the file to run as a program" and close the window.

Now that you have already given permission to the file to be able to execute it double click. When you do this you will get a window giving you several options.
Choose Execute.

To do this same from a terminal:

We give execute permissions with the command.

Sudo chmod + x [binary_name] .bin


Install the binary file with the command:

Sudo ./[binary_name


6. Packages with .sh extension

The .sh files are scripts and to execute them in the system, we double click on them and select "execute from terminal" and if some does not work we execute in a terminal the command:

Bash package-name.sh


Traditional way for all GNU-Linux:

Open a terminal, we located in the folder where the file is with the following command:

Cd address


We give permissions with:

Chmod + x packagename.sh


And we run the script with:

./numberpack.sh


If we need to do it as root, we add "sudo" to the command:

Sudo ./nombrepackage.sh



7. .run extension files
.run files are wizards, usually graphics, that help with installation. To execute them simply enter in the terminal:

Sh ./[file.run file


Normally in case you need superuser permissions (administrator) will ask for the password; Otherwise it is enough to execute in the terminal:

Sudo sh ./[file.run


8. Install from Source Code (Compile)

Packages with extension (.tar.gz) (.tar.bz2)

Sometimes there are applications that do not provide installation packages, and you have to compile them from the source code. To do this, the first thing to do in Ubuntu is to install a meta-package called build-essential. To do this, open a terminal and execute the following commands:

Sudo apt-get update
Sudo apt-get install build-essential

We may also need to install the kernel development libraries, which are required for certain packages:

Sudo apt-get install linux-headers-`uname -r`


Note: we must bear in mind that these packages may have different forms of packaging (with different files) and therefore different ways of installation, so if there is any file like "readme, leadme or txt", we must read it before Nothing in case tells us how to install.

In general, the steps to compile an application are the following:

1. Download the source code (.tar.gz or .tar.bz2).

2. As we see, by the extension .gz or .bz2 are compressed files, so we unzip the code with right click on it and choose "extract here", creating a folder with the code.

3. Enter the created directory when unzipping the code with the cd command. For example if we downloaded it in the Desktop, we put in the terminal ->

Cd Desktop / uncompressed_folder_name

Note: We put the exact name of the unzipped folder.

4. Run the "configure" script to check the system characteristics that affect the compilation, configure the compilation according to these values, and create the makefile (some packages already have it) ->

./configure


5. Run the make command, in charge of the compilation.

Make


6. Run the command, which installs the application on the system:

Sudo make install


Or better yet, install checkinstall with the command:

Sudo apt-get install checkinstall

And we can already execute:

Sudo checkinstall


The use of checkinstall also has the advantage that the system will be aware of the programs installed in that way, also facilitating their uninstallation.

Here is a complete example of this procedure:
We downloaded the package sensors-applet-0.5.1.tar.gz on the Desktop:

We decompress and get the folder sensors-applet-0.5.1

In the terminal we placed in the folder decompressed:

Cd Desktop / sensors-applet-0.5.1

We compile and install:

./configure
Make
Sudo make install

This last command we can change it by:

Sudo checkinstall

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