Complete Red Hat System Administration Boot Camp - RHCSA 9

Learn the linux directory tree from the root slash, and how essential folders like /home, /etc, /tmp, /boot, and /var/log organize users, configurations, and logs.

Explore the linux root directory at the top level and the root home at /root, and note /home/tom, /home/mary, /home/john. Root has full privileges; ordinary users access only their homes.

Learn how absolute and relative paths work in linux, using root-based paths and the cd command, and how command options and arguments may be written in short or long notation.

Use the pwd command to print the current working directory and the cd command to navigate directories, including home with tilde and the previous directory via cd -.

Learn to use the ls command to list directory contents with -l for long format, -a for hidden files, -h for human readable, -R for recursive, and -t for time.

Learn to use the date, cal, and uptime commands to display the current date, monthly or specific calendars, and system uptime with user counts and load averages.

Use lscpu to display processor information and CPU architecture, and use free to show memory with human-readable output, version, low/high memory stats, and total columns.

Use df and du to display disk usage and partitions. Show file system types with -T/--print-type and render human readable output with -h, and use -c for a total.

Use the history command to view, replay, and delete specific entries with history -d, clear the history with history -c, clear the screen with clear, and exit the terminal.

Explore how to use the whatis command to display one-line manual page descriptions. Learn how type shows the command type and how the man command accesses the online reference manuals.

Learn to use the w and last commands to show who is logged in and what they're doing, with short or long output, version info, headers, and full user names.

Learn to use uname to print system information and specific kernel details such as name, release, version, processor, and machine. Use hostname to view or change the host name.

Learn to create files with touch, set modification times with -m, use -c to avoid creation, and build nested directories with mkdir -p, then verify with ls -l.

Learn to use the cp command to copy files and directories, including recursive copies with -r, and the env command to move and rename items, with verification via ls -l.

Remove directories and files with rmdir for empty dirs and rm for files. Use -r for recursive deletion, -i to prompt, and -f to force; apply star dot txt patterns.

Learn to use the tar command to create, list (-t), extract (-x) archives, with -c, -v, -f and compression options -z, -j, or -J.

Demonstrate using the cat and echo commands to display and combine file content, redirect output, format lines with -n, and consult the man pages for options.

Learn to use head, tail, and sort commands to view first or last lines of files, customize with -n, and sort numbers using -n, examples include /etc/passwd, /etc/group, and fruit.txt.

Demonstrate using the pipe to chain commands like cat, grep, wc, and sort, and count lines, words, and characters with options and head/tail examples.

Use diff to compare f1.txt and f2.txt line by line, view results in two columns with -y, and track deletes, adds, and changes.

Learn how to use sudo for single root-privilege commands and su to switch users, including dash login shells and practical examples like viewing the shadow file and running fdisk.

Master the find command to locate files and directories from the current directory or /home, using -name, -type, -size, -user, -group, -perm, and -iname, with -exec or -delete.

Create hard links and soft links with ln and ln -s; hard links share inodes and content, soft links point to the original file and directories cannot be hard linked.

Learn to use gedit and nano editors on Linux, including syntax highlighting, fonts and colors, undo and redo, and search and replace, plus basic file creation, saving, and viewing.

Master the vi and vim editors, including command mode and insert mode, and learn essential editing commands, navigation, search and replace, and saving and quitting.

Create and delete Linux users with useradd and userdel, configuring uid, shell, expiry, and comments under /home. Manage password expiry with change age to enforce expiry rules.

Create users with specific IDs, shells, comments, and expiry dates using useradd. Delete users safely with userdel and verify details in /etc/passwd, and enforce password changes on first login.

Create groups with group add, list them with cat /etc/group, and delete with group del; use user mode to add users and modify attributes, distinguishing primary from secondary groups.

Create groups with groupadd, assign primary and secondary groups using usermod, and delete nonprimary groups with groupdel, while reviewing user IDs and group memberships.

Identify how Linux denotes file types with d, -, and L. Map read, write, and execute to 4, 2, 1 to control access and execution for files and directories.

Explore how Linux permission levels divide access among user, group, and others, using read, write, and execute values to form numeric permissions and file-type indicators.

Explore permission modes in Linux, using symbolic and absolute chmod methods to add, remove, or set rwx permissions for user, group, and others with the change mode command.

Learn to change file ownership and group membership using chown and chgrp, including changing only the owner, only the group, or both for files and directories.

Demonstrates managing file ownership and permissions with chmod, chown, and chgrp, using ls -l to read owner, group, and other rights, and changing owner or group.

Learn how umask determines default file and directory permissions with a four-digit mask (typically 0022), and how to view, set, and persist changes in .bashrc or /etc/profile.

Explore how the umask sets default permissions for files and directories, with examples like 0002 for users and 0022 for root, and observe how changes like 0026 affect created items.

Explore the three Linux special permissions—setuid, setgid, and the sticky bit—and how chmod assigns them on executables, scripts, and directories to control privileged access, with security considerations.

Explore the three special permissions, set user id, set group id, and sticky bit, and learn how they let users run executables as owners or group members, and protect files.

Learn how to change file attributes in Linux with the chattr command. Apply append only and immutable attributes to files and directories, adding or removing them with plus and minus.

Learn to manage file attributes with chattr and lsattr, using plus and minus to add or remove attributes such as append only and immutable. These attributes prevent edits or deletions.

Learn to grant superuser privileges with sudo and safely edit the sudoers file using visudo to validate syntax. Explore examples granting per-command and group privileges, passwordless access and root switching.

This demo shows how to use the superuser and sudo through visudo edits to grant passwordless privileges to users Tom and Mary, including group-based access with wheel.

Use access control lists to grant specific users and groups access to files and directories, with default ACLs for inheritance, and manage permissions via getfacl and setfacl -m for user Tom rwx.

Apply access control lists recursively to a directory and all subdirectories and files, modify user permissions to read and write, and set or remove default ACLs to control access.

Apply access control lists on files and directories to grant specific users and groups permissions, and use setfacl and getfacl for recursive and default ACL inheritance and removal.

Demonstrates adding a DNS server IP address by inspecting resolv.conf, using nslookup, and implementing a permanent DNS via the interface configuration file.

Learn to add a host with an alias by editing the /etc/hosts file, enter IP address 172.16.1.101 and a nickname, save, and verify connectivity with ping.

learn to use nmcli to control network manager, create and modify connections, view devices and active interfaces, and configure IPv4 addresses, gateway, and DNS, then activate the desired connection.

Demonstrates using nmtui, a text user interface for controlling network manager, nmcli for managing connections, to create, edit, delete, activate ethernet connections, and configure IP addresses, gateway, and DNS.

Learn to configure ntp on Red Hat 8 systems by installing the krone package, editing krone conf on server and client, enabling firewall rules, and starting chrony.

Learn how SELinux, a security enhanced Linux kernel module, enforces access control policies and how to check status, switch to permissive, and save changes via the configuration file.

Install and start the Apache httpd server, configure the document root, adjust SELinux contexts for the new directory, and enable port 81 with verification using curl.

Learn to configure Linux firewalld, view the default zone, and manage open ports and SSH service. Reload rules after changes and verify active surfaces and ports.

Explore Linux process concepts and learn to use the ps and top commands to view running processes, display all processes, filter by user, and interpret status codes.

Explore Linux process signals, list signal names with kill -l, and manage processes with pgrep, kill, and pkill. See how interrupts and term signals stop or terminate a Firefox process.

Demonstrates using scp, the secure copy protocol, to transfer files between local and remote machines, and using ssh for encrypted remote access, including ssh key pairs and passwordless login.

Explore how to switch between linux runlevel targets using systemd: list and view runlevel targets, check the current default, switch between graphical and multi-user targets, and isolate targets without reboot.

Learn how to use systemctl to manage systemd services and units, list all units, check status, start, stop, restart, enable, and disable services for reliable Linux administration.

Schedule tasks in Linux using cron by viewing, editing, and creating crontab entries with crontab commands, and automate actions with touch and rm commands for specific users.

Modify the GRUB configuration in /etc/default/grub to control the boot menu timeout and default kernel, then generate a new /boot/grub2/grub.cfg with grub2-mkconfig and reboot to load the kernel.

Learn to manage tuned profiles on Red Hat by installing tuned, checking the service, listing and switching profiles, validating the active profile, and consulting the man page for details.

Learn to install and manage package modules in Red Hat AppStream, exploring modules, streams, and profiles; use yum/dnf to list, show info, install, enable, disable, and remove modules.

Configure local Red Hat repositories for base os and app stream, define repository ids and urls, enable or disable gpg checks, and verify with repo lists.

learn to reset a forgotten root password by interrupting boot, editing grub, entering emergency mode, remounting rw, and using touch /.autorelabel to trigger relabels, then log in with new password.

Learn to create temporary files and directories using the system temp files service, configure temp dot com, and manage lifecycle with create, remove, and clean commands.

Create three partitions on /dev/sdb with fdisk, then save and inform the OS of changes with partprobe. Format sdb1, sdb2 (ext4), and sdb3 (ext fs) and update the /etc/fstab entries.

Create and configure a new swap partition on Linux by using fdisk, change type to 82, run partprobe, make swap, update /etc/fstab, and swap on.

Learn to create physical volumes, construct a volume group, and define two logical volumes with fixed size or remaining space, format with ext4, and configure mounts in fstab.

Master permanent and temporary mounts with lsblk, /etc/fstab, and mount commands, then mount and unmount partitions and logical volumes like /dev/sdb1 and vg1 lv_department1.

Learn to resize and extend logical volumes, extend volume groups with new disks, and remove physical volumes, volume groups, and logical volumes using LVM commands.

Install and configure Stratus, create a pool from multiple disks, provision file systems, snapshot and manage them, and mount them persistently while adding and removing disks as needed.

Explore video disk compression, a kernel module that saves disk space with zero-block elimination, deduplication, and data compression on any block storage device, learn to install, start, and configure.

Configure remote file systems with NFS by setting up a server and client, exporting a shared directory via /etc/exports, and mounting it on the client.

install and start autofs, configure the master map and auto.misc to mount a device on demand at /get with ext4, and observe automatic unmount after a ten second timeout.

Explore how container images provide isolated environments that run apps quickly, share the host kernel, and manage containers with Podman or Docker, including rootless execution on Red Hat systems.

Master Podman by learning to search, pull, inspect, tag, and run container images, map ports, use daemon mode, and manage environment variables for MariaDB.

Learn two methods to auto start container images under systemd user services: enable container cgroup and enable linger for per-user containers with podman.

Learn two methods to add persistent storage to container images by mounting host directories, configuring permissions, and using SELinux options, with a MySQL/MariaDB example.