In this part of RHCSA exam preparation you will learn how to manually change into a different boot targets. This article will also teach you how to set a default boot targets to automatically boot into graphical or multi-user target on Red Hat Enterprise Linux system.

In this tutorial you will learn:
  • How to check default boot target
  • How to manually switch between different targets
  • How to set default boot to multi-user target
  • How to set default boot to graphical target

In this part of RHCSA exam preparation we will turn our attention to links. There are two types of link, hard links and soft links. In this article we will talk about how to create and remove links and will also discuss some basic background behind both, the hard links and the soft links.

In this tutorial you will learn:
  • What are symbolic (soft) links
  • What are hard links
  • How to create a symbolic link
  • How to create a hard link
  • How to remove link

RHCSA is a must have certification for anyone serious about getting a Linux system administration job. This RHCSA Exam Preparation Guide is currently under construction but is regularly updated with new topics. Please check back later.

If you are a beginner or somewhat new to GNU/Linux do not waste time by waiting but get started with a GNU/Linux command line basics before you do anything else. Understanding the GNU/Linux command line is an absolute must and will take you a long way on your RHCSA exam.

Understand and use essential tools

Operate running systems

  • Boot, reboot, and shut down a system normally
  • Boot systems into different targets manually
  • Interrupt the boot process in order to gain access to a system
  • Identify CPU/memory intensive processes and kill processes
  • Adjust process scheduling
  • Locate and interpret system log files and journals
  • Preserve system journals
  • Start, stop, and check the status of network services
  • Securely transfer files between systems

Configure local storage

  • List, create, delete partitions on MBR and GPT disks
  • Create and remove physical volumes
  • Assign physical volumes to volume groups
  • Create and delete logical volumes
  • Configure systems to mount file systems at boot by universally unique ID (UUID) or label
  • Add new partitions and logical volumes, and swap to a system non-destructively

Create and configure file systems

  • Create, mount, unmount, and use vfat, ext4, and xfs file systems
  • Mount and unmount network file systems using NFS
  • Extend existing logical volumes
  • Create and configure set-GID directories for collaboration
  • Configure disk compression
  • Manage layered storage
  • Diagnose and correct file permission problems

Deploy, configure, and maintain systems

  • Schedule tasks using at and cron
  • Start and stop services and configure services to start automatically at boot
  • Configure systems to boot into a specific target automatically
  • Configure time service clients
  • Install and update software packages from Red Hat Network, a remote repository, or from the local file system
  • Work with package module streams
  • Modify the system bootloader

Manage basic networking

  • Configure IPv4 and IPv6 addresses
  • Configure hostname resolution
  • Configure network services to start automatically at boot
  • Restrict network access using firewall-cmd/firewall

Manage users and groups

  • Create, delete, and modify local user accounts
  • Change passwords and adjust password aging for local user accounts
  • Create, delete, and modify local groups and group memberships
  • Configure superuser access

Manage security

  • Configure firewall settings using firewall-cmd/firewalld
  • Configure key-based authentication for SSH
  • Set enforcing and permissive modes for SELinux
  • List and identify SELinux file and process context
  • Restore default file contexts
  • Use boolean settings to modify system SELinux settings
  • Diagnose and address routine SELinux policy violations
The hostname of your CentOS 7 Linux is defined by the file /etc/hostname thus setting a new hostname for your system is just a matter of editing this file and replace a current hostname definition line with new one. However, doing so will not update your system;s hostname immediately thus a preferred way of changing a hostname on CentOS 7 Linux is to use nmtui and more specifically its child nmtui-hostname. Using nmtui-hostname tool will make the process of changing your hostname rather simple as executing a single command. The following linux command will change the hostname to
# nmtui-hostname
hostname change centos 7 linux command
Hit the "OK" button on the pop-up dialog and you are done.

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