SSA1.pdf

IT1917 Linux Environment An operating system (OS) is the sum of all programs which are required to operate a computer. It is also used to control and monitor application programs. UNIX has been o...

IT1917 Linux Environment An operating system (OS) is the sum of all programs which are required to operate a computer. It is also used to control and monitor application programs. UNIX has been originally written in the programming language C, and it is mainly used for scientific-technical applications on mainframes and workstations but has also become perfectly suited for application in networks. Originally, it is command-line oriented, but can be used via a graphical user interface. Linux is a family of UNIX-like open-source operating system developed by Linus Torvalds. As an open-source operating system, there are instances that the source code of the Linux Kernel (main component of a Linux OS) is used to form another operating system. A Linux distribution (distro) is a collection of software on top of a Linux kernel. It can bundle server software, system management tools, documentation, and many desktop applications in a central, secure software repository. A distro aims to provide a common look and feel, secure and easy software management, and often a specific operational purpose. Linux Environment Shells are interfaces to the operating system, the kernel of the host. It provides the necessary instruction and operation that an operating system may process. It can be in two forms: A GUI (Graphical User Interface) is a graphical representation in which the users can interact with software or devices through graphical icons. A CLI (Command Line Interface) is a console or text-based representation in which the user types the commands to operate the software or devices. When it comes to ease of use, the new users will pick up a GUI much faster than a CLI. New users of CLI will have some difficulty operating it because they are not familiar with the commands. When it comes to controlling the system, CLI users will have all the control over the file system and operating system, and the tasks become simple through scripting, while GUI users can do only simple and limited tasks not flexible enough for controlling the system. Linux Desktop Environments (GUI) GNOME was once the most popular Linux desktop environment and was used by default on Ubuntu, Fedora, Debian, and most other big Linux distributions. It was a simple, fairly lightweight desktop environment. KDE has always been more complex than GNOME, packing in many more configuration options and features. It’s a bit more Windows-like than the other desktop environments here, coming with a single taskbar on the bottom of the screen that includes a menu, quick launch-type icons, a taskbar, a notification area, and a clock — the typical layout of a Windows taskbar. Xfce is a more lightweight desktop environment, very similar to GNOME. This option is ideal if you want a more traditional desktop environment without full-screen application launchers, overdone graphical effects, and desktop widgets. It’s also more lightweight than the other options, making it ideal for older computers or ones without stable 3D graphics drivers that can’t handle the effects in Unity and GNOME. Cinnamon was developed for Linux Mint in which it is based on GNOME. It uses up-to-date libraries and other software — but it takes that software and tries to create a more traditional-looking desktop with it. This modern desktop environment offers nice graphical effects and a rethought application menu. 01 Handout 1 *Property of STI  [email protected] Page 1 of 4  IT1917 Basic Linux Commands with Syntaxes Commands Description Example Output: man displays user manual of any (Manual) command on the terminal file determines the type of a file. (Filetype) whatis displays short descriptions of program whereis locates files and pages of a command whoami displays the current user ls displays the list of files and (List) directory 1st col. - permissions 2nd col. - no. of links 3rd col. – file/dir. owner 4th col. - file/dir. group 5th col. - size 6th col. - date stamp 7th col. - timestamp 8th col. - name tree displays the contents of the working directory recursively showing sub-directories and files, and a summary of the total number of sub-directories and files pwd displays parent working (Parent directory Working Directory) cd changes the current directory (Change - cd.. - previous folder Directory) - cd / - root folder - cd ~ - shortcut 01 Handout 1 *Property of STI  [email protected] Page 2 of 4  IT1917 mkdir creates directory (Make Directory) rmdir removes directory (Remove Directory) cp copies a file to a specified (Copy File) location mv moves a file to a specified (Move File) location rm removes a file. (Remove File) File Management and Structure All files are organized into directories. These directories are organized into a tree-like structure called the filesystem. In Linux, there are three basic types of files: Ordinary Files − An ordinary file is a file on the system that contains data, text, or program instructions. Directories − Directories store both special and ordinary files. For users familiar with Windows or Mac OS, Unix directories are equivalent to folders. Special Files − Some special files provide access to hardware such as hard drives, CD-ROM drives, modems, and Ethernet adapters. Other special files are similar to aliases or shortcuts and enable you to access a single file using different names. Linux Directories / (root directory) refers to the root directory. The /dev contains device files. Many of these are root directory is the one from which all other generated at boot time or even on the fly. directories branch off from. /etc. is the dumping ground for system files /bin is the directory that contains binaries, that administrators were not sure where else to put. is, some of the applications and programs you /home is where you will find your users’ can run. personal directories. /boot directory contains files required for /lib is where libraries live. Libraries are files starting your system. containing code that your applications can use. 01 Handout 1 *Property of STI  [email protected] Page 3 of 4  IT1917 They contain snippets of code that applications command that temporarily concedes you use to draw windows on your desktop, control superuser powers on many distributions. peripherals, or send files to your hard disk. /usr directory was where users’ home /opt directory is often where the software you directories were originally kept back in the early compile. Applications will end up in the /opt/bin days of UNIX. It contains a mish-mash of directory and libraries in the /opt/lib directory. directories, which in turn contain applications, /proc and /dev are virtual directory in which it libraries, documentation, wallpapers, icons, and contains information about your computers, a long list of other stuff that needs to be shared such as information about your CPU and the by applications and services. kernel your Linux system is running. It is a /tmp contains temporary files, usually placed directory in which it contains the files and there by applications that you are running. The directories are generated when your computer files and directories often (not always) contain starts, or on the fly, as the system is running data that an application doesn’t need right now, and things change. but may need later on. /sbin is similar to /bin, but it contains /var was originally given its name because its applications that only the superuser will need. contents were deemed variable in which it You can use these applications with the sudo contains files to which the system writes data during the course of its operation. References: Brown, P. (2018). The Linux Filesystem Explained. Retrieved on December 18, 2019 from https://www.linux.com/tutorials/linux-filesystem-explained/ File Permissions in Linux/Unix with Example. In Guru99.com. Retrieved on December 18, 2019 from https://www.guru99.com/file-permissions.html Hoffman, C. (July 11, 2017). Linux Users Have a Choice: 8 Linux Desktop Environments. Retrieved on December 18, 2019 from https://www.howtogeek.com/163154/linux-users-have-a-choice-8-linux-desktop-environments/ LaCroix, J. (2015). Mastering Linux Network Administration. Birmingham, UK: Packt. Limoncelli, T., et. al. (2017). The Practice of System and Network Administration (3rd ed.). USA: Addison-Wesley. Matotek, D. et. al. (2017). Pro Linux System Administration – Learn to Build Systems for Your Business Using Free and Open Source Software (2nd ed.). New York: Apress. Nemeth, E. et. al. (2018). Unix and Linux System Administration Handbook (5th ed.). USA: Addison-Wesley. System Administration: Configure, Deploy, Maintain and Audit. (2012). System Administration Book. Retrieved on October 2019 from http://www.ansatt.hig.no/erikh/sysadm/wikipedia-sysadm-book- 30072012.pdf Unix / Linux - File Management. In Tutorialspoint.com. Retrieved on December 18, 2019 from https://www.tutorialspoint.com/unix/unix-file-management.html Verma, A. (April 4, 2019). In Fossbytes.com: 12 Best Text Editors For Linux And Programming In 2019. Retrieved on December 18, 2019 from https://fossbytes.com/9-best-text-editors-linux-programming-2017/ 01 Handout 1 *Property of STI  [email protected] Page 4 of 4