Words to go: learn basic Linux terminology
The Linux operating system is a community-developed, open-source operating system for computers and servers, and is one of the most widely used and supported operating systems. It manages hardware resources and applications and provides a user interface for use by administrators and developers.
For administrators new to using Linux, some of the terminology can seem daunting. However, knowing key Linux terms can help anyone better understand this commonly used operating system.
A Linux distribution – or distro – represents a specific version of the Linux operating system bundled with other components, including installers, management tools, or other software. Linux distributions are designed for easier deployment than the basic open source version of Linux, as they eliminate additional manual completion of the operating system. Each Linux distribution targets specific users or systems, and most are out of the box.
Popular Linux distributions include Red Hat Enterprise Linux (RHEL), OpenSUSE, Ubuntu, and Oracle Linux. Some commercial distributions charge users for support, but the open source nature of Linux prevents vendors from charging Linux itself.
Linux swaps pages based on inactivity rather than waiting for all available memory to be used. Linux swapping describes the rate at which a Linux kernel can move pages in and out of active memory. Users can fine-tune the swapping by adjusting the swapping parameter, which is set on a scale between 0 and 100. Linux servers automatically default to 60.
A Linux stream refers to data traveling from one process to another in a Linux shell. Create a Linux stream by entering characters from a keyboard. Edit the stream by editing the stream text with Linux commands such as sed. Stream characters are either standard input or standard output of a process or file. From the CLI, the pipe and redirect commands control input and output streams.
Xen is the open source hypervisor that the Linux kernel uses by default. It comes with all Linux distributions and consists of several different parts. Domain 0 refers to the host operating system, which accesses drivers and handles coordination. The U domain refers to other virtual machines running on Xen. It offers two varieties of virtualization: paravirtualization and full virtualization. Paravirtualization runs a modified version of the operating system with more efficient communication between the operating system and the hardware, but requires a modified guest operating system that many vendors do not provide. Full virtualization uses unmodified guest operating systems and requires the processor to support virtualization extensions.
KVM is another open source hypervisor for Linux distributions. Unlike Xen, KVM uses the Linux kernel as a type 2 hypervisor, which creates VM environments and coordinates processor memory, hard disk, and network resources through the host operating system. It works with a variety of guest operating systems and can be installed with the Linux kernel.
Rsync is a software utility for Linux users that copies files and directories from one host to another. It transfers files incrementally and provides offsite backups by synchronizing data outside a firewall. Use it to update directory trees and file systems or to preserve links, file ownership, permissions, devices and times. It is available on most Linux distributions by default.
SUSE Manager is an infrastructure management tool for Linux systems. It performs various tasks, including automating Linux server provisioning; configuration and patches; inventory management and asset tracking for hardware and software; server monitoring and reporting; and compliance and security monitoring. SUSE Manager can manage on-premises and cloud workloads. It can also manage Linux distributions on different hardware platforms and virtualization environments. A variety of other hardware and software management tools integrate with SUSE Manager to provide even more comprehensive management across an entire Linux environment.
Cygwin is a collection of tools that allows Linux applications to run on a Windows operating system and create a Linux-like experience on Windows. This allows applications to be migrated from Linux-based systems to Windows-based systems without requiring developers to make major changes to the source code of those applications. Cygwin is based on the dynamic link library, which acts as an emulation layer, but Cygwin also comes with a collection of free tools. Users can access the Cygwin environment through the Windows command shell or through the Unix shell, and issue Unix commands the same way they would on a Unix or Linux operating system.