Linux Tutorials and Command Line Guides - Page 2

Install cURL on Ubuntu 26.04, 24.04, or 22.04 with APT, verify HTTPS access and package versions, understand curl vs libcurl, and safely update or remove curl.

Install Caddy on Ubuntu 26.04 or 24.04 from the official APT repository, verify caddy.service, serve a static site with a Caddyfile, open UFW ports 80 and 443, and enable automatic HTTPS for a public domain or localhost.

Install CMake on Ubuntu 26.04, 24.04, or 22.04 with apt, Kitware's repository, Snap, or official binaries, and verify which CMake version your project needs with cmake --version and a minimal C++ build.

Install ClamAV on Ubuntu 26.04, 24.04, and 22.04, keep malware signatures current with FreshClam, verify detection with the EICAR test file, and choose clamscan or clamdscan for on-demand scans.

Install Boost C++ on Ubuntu 22.04, 24.04, or 26.04 with libboost-dev, libboost-all-dev, or component packages from apt, or build Boost 1.92 from archives.boost.io, verify with a compile test, and link with g++ or CMake …

Install chkrootkit on Ubuntu 26.04, 24.04, and 22.04 from Universe, run rootkit scans with chkrootkit -q, read INFECTED and PACKET SNIFFER output safely, enable daily scans (systemd timer or packaged cron), and optional …

Install AWS CLI v2 on Ubuntu 26.04, 24.04, and 22.04 using the official AWS installer, ZIP, Snap, or Ubuntu APT. Compare release-specific package availability, verify aws --version, authenticate securely, update, and fix …

Ubuntu volume too low? Learn how to increase sound above 100% on Ubuntu 26.04 and 24.04 using Over-Amplification or the PipeWire wpctl command.

Update Flameshot on Ubuntu 26.04 and 24.04 from APT, see why apt upgrade stops at 13.3 or 12.1, and move to Flameshot 14 with Flatpak or the latest AppImage without mixing release repositories.

Install PhotoQt on Ubuntu 26.04, 24.04, or 22.04 with APT, Flatpak, Snap, or the PhotoQt PPA. Includes version checks, launch, update, and removal.

Uninstall software on Ubuntu 26.04 by matching the install method—apt remove or purge for Deb packages, snap remove, flatpak uninstall, App Center Manage, and safe autoremove simulation before you confirm dependency …

Install HPLIP on Ubuntu 26.04 and 24.04 with apt first, check your printer minimum HPLIP version against Ubuntu packages, use hp-setup and hp-plugin when needed, and only consider HP SourceForge .run when upstream …

Install the Google Dart programming language SDK on Ubuntu 26.04 and 24.04 from the official APT repository, verify with dart --version, run Hello World, upgrade through apt, and know when Flutter already includes Dart.

Ubuntu does not ship Windows-style real-time antivirus. Learn when a home desktop can skip AV, when file or mail servers should scan with ClamAV, what AppArmor and updates already provide on Ubuntu 26.04, and where to …

Check whether an x86 CPU supports 2 MB or 1 GB HugePages, find the current HugeTLB default size, and change default_hugepagesz persistently with grubby on RHEL.

Increase or shrink tmpfs on Linux with size=, /etc/fstab, and mount -o remount. Covers /dev/shm, /run, and systemd /run/user limits on RHEL-family systems.

Authenticate vsftpd FTP logins with Active Directory on RHEL 10 through PAM and SSSD, with deprecation notes, SELinux, passive ports, and tests—prefer SFTP for new deployments.

Let Active Directory users transfer files over SFTP on RHEL 10 after a realmd and SSSD join: sshd, PAM, home directories, optional chroot, and verification from Linux clients.

Learn how to check whether SSH is using protocol 1 or 2, what OpenSSH version strings such as OpenSSH_7.4p1 mean, and how to read SSH-2.0 banners and verbose SSH output.

Automate password-based SSH and SCP in Linux using sshpass, Expect, and SSH_ASKPASS, with safer password input, host-key handling, and key-based alternatives.

Mount a remote Linux directory over SSH with SSHFS on RHEL, Ubuntu, and Windows. Covers install, user mounts, permissions, fstab, jump hosts, SSHFS-Win UNC paths, and troubleshooting.

Configure OpenSSH host-based authentication on Linux with HostbasedAuthentication, ssh-keysign, shosts.equiv, and verified host keys—plus hostname/DNS checks and safer alternatives.

Test SSH connectivity in Linux step by step: check port 22, verify that sshd responds, test authentication, inspect server-side sshd status, and troubleshoot common SSH errors.

Connect to private Linux servers through an SSH jump or bastion host using ProxyJump, ssh -J, ProxyCommand, and scp -J, with multi-hop routes and troubleshooting examples.

SSH from your host into a Linux VirtualBox VM using NAT port forwarding (recommended), host-only networking, or a bridged adapter — with a mode decision table, guest SSH checks, and troubleshooting for 10.0.2.15 and VPN …

Use OpenSSH host certificates so clients trust one host CA through @cert-authority in known_hosts instead of enrolling every server host key — create a host CA, sign with ssh-keygen -h, configure HostCertificate on sshd, …

Understand sshd ssh-rsa algorithm is disabled on RHEL 9 and 10, when RSA-SHA2 logins still work, and when to upgrade clients or allow a scoped ssh-rsa exception.

Sign files with ssh-keygen -Y sign, verify them with an allowed_signers file, signer identity, namespace, and stdin — no sshd or GPG required on OpenSSH 8.2 and later.

Fix SSH no matching key exchange method found by reading Their offer:, enabling the required KEX algorithm safely, and resolving follow-on host-key or cipher errors.

Fix SSH "Bad server host key: Invalid key length" caused by 1024-bit RSA host keys, RequiredRSASize, RHEL crypto policies, or stale known_hosts entries.