Linux Tutorials and Command Line Guides - Page 13

Install OpenSSL on Ubuntu with apt (openssl and libssl-dev), verify with openssl version, understand when the distro package is enough versus building from source, and generate a test TLS key and certificate.

Generate a self-signed SSL certificate with OpenSSL in one command or via CSR: RSA 2048/4096, EC, Ed25519, SAN for localhost and IP addresses, encrypted keys, and nginx-ready PEM files. Copy-paste examples with real …

Should you disable Transparent HugePages on Linux? Compare enabled always, madvise, and never, understand the defrag knob, see benchmark results for THP collapse and fork COW, and get workload-specific guidance for …

Do you need swap on Linux? Learn when swap adds value under memory pressure, what happens without it (OOM killer), how vm.swappiness differs for servers and desktops, swapfile vs partition, and how to tune sysctl safely.

Compare Ubuntu 26.04 LTS and Linux Mint 22.3 in 2026: downstream Mint on Noble vs Canonical Ubuntu, GNOME vs Cinnamon, snap vs Flatpak policy, Mint tools, support timelines, hardware, developers, and which to install.

Compare Ubuntu 26.04 LTS and Fedora Linux 44 in 2026: Debian-derived APT vs RHEL-upstream DNF, five-year LTS vs 13-month releases, snap vs Flatpak, AppArmor vs SELinux, cloud and enterprise fit, and practical desktop …

Compare Ubuntu 26.04 LTS Server and Desktop in 2026: same archive and kernel, different metapackages, RAM and disk requirements, installers, headless vs GNOME, cloud images, adding a GUI, and when to pick each edition.

Unsupported two-hop downgrade Ubuntu 26.04 LTS to 25.04 via 25.10 using apt pinning and aptitude—no data loss under /home on our VirtualBox VM—reboot between hops, Python and GRUB failures, libc6 hybrid state, and when …

Upgrade Ubuntu 25.04 to 26.04 LTS with do-release-upgrade via the required 25.10 hop—no data loss on /home in our VirtualBox test—apt full-upgrade and reboot checks, and fixes when the upgrader blocks on a pending reboot …

List obsolete packages on Ubuntu with apt list ?obsolete, preview removal with apt-get -s, purge safely after do-release-upgrade, and distinguish obsolete packages from autoremove and rc config cleanup.

Downgrade Ubuntu 21.04 (Hirsute Hippo) to 20.04 LTS (Focal Fossa) with apt pinning, sources.list retargeting, and aptitude dist-upgrade—no data loss under /home when the run completes, plus dpkg recovery, reboot checks, …

Learn how to check Ubuntu version from the command line or GUI. Use lsb_release, /etc/os-release, hostnamectl, /etc/issue, or Settings to find your Ubuntu release, version number, codename, and kernel.

Compare Kubuntu 26.04 LTS and Ubuntu MATE 24.04/25.10 in 2026: KDE Plasma vs MATE desktop, support timelines, hardware fit, customization, Wayland, applications, and which official Ubuntu flavor to pick for your PC.

Compare Debian 12 Bookworm and Ubuntu 24.04 LTS Noble for servers: release cycles, security support, package freshness, Snap vs pure APT, cloud images, resource use, and when to pick each distro for production workloads.

Compare Debian 12 Bookworm and Debian 11 Bullseye in 2026: full support vs LTS timelines, OpenSSL 3 and Python 3.11 jumps, package versions, upgrade paths to Trixie, and when to stay on each release.

Compare Arch Linux and Ubuntu 26.04 LTS in 2026: rolling release vs LTS cadence, pacman vs APT, AUR vs snap, DIY minimal install vs GNOME desktop, cloud and enterprise fit, security defaults, and practical guidance.

Compare openSUSE Leap 16 and Tumbleweed with Debian 13 Trixie: fixed vs rolling release, zypper vs APT, SELinux vs AppArmor, btrfs and Snapper, Agama and Cockpit, support timelines, servers, and practical guidance for …

Compare Linux Mint 22.x and LMDE 7 with Debian 13 Trixie: Ubuntu-based vs pure Debian, Cinnamon desktop polish, snap vs Flatpak, support timelines, servers, upgrades, and practical guidance for choosing between them.

Compare Arch Linux and Debian 13 Trixie: rolling release vs stable, pacman vs APT, AUR vs official repos, install philosophy, security defaults, server fit, upgrades, and practical guidance for choosing between them.

Install AWS CLI on Debian 11, 12, or 13 with the official awscli-exe-linux bundle, apt install awscli on Trixie, or legacy pip awscli. Verify with aws --version, configure credentials, fix PATH conflicts, and uninstall …

Install Flatpak on Debian 11, 12, or 13 with apt install flatpak, add the Flathub remote, install sandboxed apps with flatpak install, update with flatpak update, and remove Flatpak cleanly from system or user scope.

Install Go on Debian 11, 12, or 13 with apt install golang-go, the official go.dev Linux tarball under /usr/local/go, PATH and GOPATH setup, go mod init, verify with go version, and uninstall without mixing two …

Install ifconfig on Debian 11, 12, or 13 with apt install net-tools, fix ifconfig command not found on minimal images, compare with ip from iproute2, verify interfaces, and uninstall net-tools cleanly.

Install netstat on Debian 11, 12, or 13 with apt install net-tools, fix netstat command not found on minimal images, compare listening ports and routes with ss from iproute2, and remove net-tools cleanly.

Install PostgreSQL on Debian 11, 12, or 13 with apt install postgresql, verify systemd and psql, create users and databases, add the PGDG repository for other majors, and remove clusters cleanly with pg_dropcluster.

Install curl on Debian 11, 12, or 13 with sudo apt install curl, verify with curl --version and an HTTPS request, fix curl command not found and libcurl4t64 dependency errors, install php-curl when PHP needs libcurl, and …

Install Java on Debian 11, 12, or 13 with apt install openjdk-21-jdk or openjdk-25-jdk, default-jdk metapackages, Eclipse Temurin from Adoptium, and update-java-alternatives. Set JAVA_HOME, verify java -version, compile …

Install Wine on Debian 11, 12, or 13 with apt install wine and i386 multiarch, add the WineHQ repository for winehq-stable or staging, initialize a WINEPREFIX with wineboot, use winetricks for runtimes, and uninstall …

Install Firefox on Debian 11, 12, or 13 with firefox-esr from Debian, the official Mozilla APT repository for the latest release, Snap, Flatpak, or a .tar.xz from firefox.com. Verify versions, set the default browser, …

Install the latest Python on Debian 11, 12, or 13 without breaking system python3: use apt for the distro version, uv or pyenv for upstream releases, or make altinstall from python.org. Create a venv, verify with python …