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Cheatsheet

Introduction to Linux

Linux is a fully multitasking (i.e., multiple threads of execution are performed simultaneously), multiuser operating system with built-in networking and service processes known as daemons in the UNIX world.

Linux is an operating system and its core is just a kernel. It talks to the hardware makes the hardware work. It makes it able for you to run programs and do what you want to do.

how to use the command line; how to use the graphical interface.

keep in mind most of the documentation in Linux is actually already on your system in the form of man pages

NOTE: Linux was inspired by UNIX, but it is not UNIX.

Common Terminology

  • Kernel: The kernel is considered the brain of the Linux operating system. It controls the hardware and makes the hardware interact with the applications.

  • Distribution: A distribution also known as Distros is a collection of programs combined with the Linux kernel to make up a Linux-based operating system. Some common examples of a distribution are Red Hat Enterprise Linux, Fedora, Ubuntu, and Gentoo.

    Distribution consists of the kernel plus a number of other software tools for file-related operations, user management, and software package management.

  • Bootloader: The boot loader, as the name implies, is a program that boots the operating system. Two examples of a boot loader are GRUB and ISOLINUX.

  • Services: A service is a program that runs as a background process. Some examples of the service are httpd, nfsd, ntpd, ftpd and named.

  • Filesystem: A filesystem is a method for storing and organizing files in Linux. Some examples of filesystems are ext3, ext4, FAT, XFS and Btrfs.

  • X window system: The X Window System provides the standard toolkit and protocol to build graphical user interfaces on nearly all Linux systems.

  • Desktop Environment: The desktop environment is a graphical user interface on top of the operating system. GNOME, KDE, Xfce and Fluxbox are some examples of the desktop environment.

  • Command Line: The command line is an interface for typing commands on top of the operating system.

  • Shell: The Shell is the command line interpreter that interprets the command line input and instructs the operating system to perform any necessary tasks and commands. For example, bash, tcsh and zsh.