Book Image

Red Hat Enterprise Linux 8 Essentials

By : Neil Smyth
1 (1)
Book Image

Red Hat Enterprise Linux 8 Essentials

1 (1)
By: Neil Smyth

Overview of this book

Red Hat Enterprise Linux 8 is one of the most secure and dependable operating systems available. For this reason, the ambitious system or network engineer will find a working knowledge of Red Hat Enterprise 8 to be an invaluable advantage in their respective fields. This book, now updated for RHEL 8.1, begins with a history of Red Enterprise Linux and its installation. You will be virtually perform remote system administration tasks with cockpit web interface and write shell scripts to maintain server-based systems without desktop installation. Then, you will set up a firewall system using a secure shell and enable remote access to Gnome desktop environment with virtual network computing (VNC). You’ll share files between the Red Hat Enterprise Linux 8 (RHEL 8) and Windows System using Samba client and NFS. You will also run multiple guest operating systems using virtualization and Linux containers, and host websites using RHEL 8 by installing an Apache web server. Finally, you will create logical disks using logical volume management and implement swap space to maintain the performance of a RHEL 8 system. By the end of this book, you will be armed with the skills and knowledge to install the RHEL 8 operating system and use it expertly.
Table of Contents (32 chapters)
32
Index

8.12 Environment Variables

Shell environment variables provide temporary storage of data and configuration settings. The shell itself sets up a number of environment variables that may be changed by the user to modify the behavior of the shell. A listing of currently defined variables may be obtained using the env command:

$ env

SSH_CONNECTION=192.168.0.19 61231 192.168.0.28 22

MODULES_RUN_QUARANTINE=LD_LIBRARY_PATH

LANG=en_US.UTF-8

HISTCONTROL=ignoredups

HOSTNAME=RHEL-pc.ebookfrenzy.com

XDG_SESSION_ID=15

MODULES_CMD=/usr/share/Modules/libexec/modulecmd.tcl

USER=demo

ENV=/usr/share/Modules/init/profile.sh

SELINUX_ROLE_REQUESTED=

PWD=/home/demo

HOME=/home/demo

SSH_CLIENT=192.168.0.19 61231 22

SELINUX_LEVEL_REQUESTED=

.

.

.

Perhaps the most useful environment variable is PATH. This defines the directories in which the shell will search for commands entered at the command prompt, and the order in which it will do so. The PATH environment...