Linux Tutorials and Command Line Guides - Page 7

Kickstart %post script examples on RHEL 10: chrooted post-install tasks, --nochroot log copy, --interpreter for Python and Bash, systemctl enable, and lab verification script.

Learn how Linux umask masks permissions at file creation: calculate modes from typical 0666 and 0777 requests, set session and persistent umask, configure systemd UMask, and troubleshoot common mistakes.

Build a Kickstart PXE boot server on RHEL 10 with Apache HTTP, dnsmasq DHCP and TFTP, BIOS pxelinux and HTTP iPXE, local inst.stage2 from DVD, and inst.ks delivery for automated netboot installs.

Get RHEL at no cost with the Red Hat Developer Subscription for Individuals: create an account, activate the subscription, pick the Boot or DVD ISO, and verify the download.

Register RHEL with subscription-manager, verify Simple Content Access, enable BaseOS and AppStream repositories, configure a proxy, and unregister.

Configure SELinux port labels and booleans on Linux: read name_bind denials, add a port to http_port_t with semanage port, use -m when a port is already defined, and switch optional behaviour with getsebool and setsebool …

Manage SELinux modes and file contexts on Linux: getenforce and setenforce, ls -Z, matchpathcon, restorecon, semanage fcontext, AVC denials, and an httpd content fix without disabling SELinux.

Learn how Linux resolves hostnames through NSS, /etc/hosts, and DNS: use getent hosts and getent ahosts, dig and host, configure DNS servers and search domains with nmcli, and troubleshoot resolution failures.

Configure GRUB2 on RHEL with grubby and BLS entries: list kernels, set the default boot kernel, add or remove kernel parameters, use /etc/default/grub with grub2-mkconfig, and recover from bad boot arguments.

Schedule recurring and boot-relative jobs with systemd timers: pair a timer unit with a service unit, use OnCalendar and monotonic triggers, enable with systemctl, inspect list-timers and journalctl, and compare timers …

Manage TuneD profiles in Linux with tuned-adm: list and read profiles, apply throughput-performance, check the recommendation, verify applied settings, inspect tuned.conf inheritance, and revert cleanly.

Reset a forgotten root password on RHEL 10 from the GRUB menu with rd.break, remount /sysroot, chroot, passwd, and SELinux autorelabel before you log in again.

Learn systemd targets as boot synchronization points: get-default, set-default, isolate multi-user or graphical, rescue and emergency mode, and one-boot overrides with systemd.unit=.

Reboot, power off and shut down Linux with systemctl and shutdown. Schedule or cancel reboots, notify users, and verify the new boot.

Install Flatpak on Linux, configure remotes, search Flathub or vendor catalogs, install update and remove sandboxed apps with flatpak run, permissions, and troubleshooting.

Learn Linux file permissions and ownership: rwx for files vs directories, chmod symbolic and octal modes, chown and chgrp, umask, SUID SGID sticky bit, and permission denied diagnosis.

Create and edit Linux text files with Vim, Nano, touch, redirection, search and replace, backups, and safe configuration edits from the command line.

Learn Linux stdin, stdout and stderr redirection with >, >>, 2>&1, pipes, tee, /dev/null, here documents, PIPESTATUS and pipefail.

Learn Linux command line basics: how the shell parses commands, navigate with paths, use quoting and expansion, find help with man and --help, and practice safe identity checks before you move on to file management and …

Understand the Linux filesystem hierarchy—what /etc, /var, /usr, and /home contain—and navigate with absolute and relative paths using pwd, cd, ls, file, stat, and find.

Manage Linux processes with ps, pgrep, top, jobs, signals, and systemctl. Find high-CPU tasks, inspect process states, and stop processes safely.

Install DVWA on Kali Linux with the native dvwa package, Docker Compose, or a manual Apache and MariaDB stack, then verify port 42001 or 4280 and fix common setup errors.

Install OWASP Juice Shop on Kali Linux using the native package, Docker, or Node.js source, then verify access, connect Burp Suite, and fix common errors.

Learn the Linux boot process from UEFI or BIOS through GRUB, the kernel, initramfs, and systemd, with inspection commands and troubleshooting.

Create coordinated LVM snapshot sets with snapm, boot into a snapshot through Boom and GRUB, inspect an earlier system state, revert failed changes, monitor snapshot capacity, and delete snapshot sets on Rocky Linux …

Convert an existing dhcpd.conf to Kea JSON with KeaMA, correct unsupported directives, test reservations and leases on an isolated lab, compare DHCP offers, and cut over from ISC DHCP to Kea with a tested rollback path.

Install and configure the Kea DHCPv4 server on Rocky Linux 10, RHEL 10, or AlmaLinux 10 with a JSON address pool, gateway and DNS options, MAC reservation, and lease verification on an isolated lab network.

Reset or change the Directory Manager password in 389 Directory Server with online dsconf over LDAPS, offline pwdhash and dse.ldif editing, verification, rollback, and per-replica rollout.

Troubleshoot slow LDAP searches in 389 Directory Server using client timing, access-log metrics, unindexed-filter notes, indexes, caches, and replica comparison.

Fix missing or stale memberOf in 389 Directory Server by checking group data, plug-in scope, fix-up filters, shared configuration, and replication.