Every user working with Git needs an SSH key pair for authentication. Generate one if you don’t have it: ssh-keygen -t ed25519 -C “your-email@example.com” Ed25519 keys are preferred over RSA for better security and performance. The command creates ~/.ssh/id_ed25519 (private key) and ~/.ssh/id_ed25519.pub (public key). Share the public key with your Git server administrator to…
MPlayer reached end-of-life years ago. Its active fork, mpv, maintains all screenshot functionality with identical or simpler syntax. This guide covers mpv, which handles both single captures and burst sequences. Enable Screenshot Support Screenshot support is built into mpv by default — no filter loading required. However, you can customize behavior by adding configuration to…
pgrep and pkill are essential tools for finding and signaling processes by name and attributes. They’re far more precise than grepping ps output and should be your go-to for process management scripts and one-liners. pgrep: Find Process IDs pgrep searches running processes and outputs matching PIDs. All selection criteria must match unless you use alternatives…
LVM snapshots provide an efficient way to duplicate virtual machines in seconds rather than minutes. Instead of copying an entire filesystem, snapshots leverage copy-on-write semantics—physical blocks are only duplicated when the source or snapshot is modified. This approach works well for any LVM-backed virtualization platform, though Xen is used here as an example. Note: Xen…
Building and maintaining Linux clusters requires coordinated management of user accounts, storage, networking, and services across multiple machines. This guide covers practical approaches to common clustering challenges, from unified authentication to network isolation. Account and Storage Management Unified Authentication and Home Directories Centralizing user management across cluster nodes eliminates the overhead of maintaining individual user…
GNOME has hidden a few playful easter eggs in its desktop environment over the years. Two of the most well-known are “Free the Fish” and “Wanda the Fish” — small animated features that surprise unsuspecting users. Free the Fish (GNOME 2) In GNOME 2, pressing Alt+F2 and running this command: free the fish releases a…
A Fedora Live USB lets you boot directly into a Fedora environment without modifying your hard drive. You can use it to test Fedora, troubleshoot your system, or perform a fresh installation. This guide covers modern tools and workflows for creating bootable USB media. Back up any data on your USB stick first — the…
To find all available versions of a package in your repository, use the –showduplicates flag: dnf list –showduplicates kernel Or for other packages: dnf list –showduplicates <package-name> The output shows both installed and available versions with their release tags. For example: Installed Packages kernel.x86_64 6.8.1-1.fc39 @updates Available Packages kernel.x86_64 6.7.12-200.fc39 updates kernel.x86_64 6.6.25-1.fc39 updates kernel.x86_64…
Understanding and managing system time is crucial for logging, cron jobs, SSL certificates, and system synchronization. Here’s how to handle it properly on modern Linux systems. Unix Time (POSIX Time) Unix time represents seconds elapsed since 00:00:00 UTC on January 1, 1970, excluding leap seconds. Get the current Unix timestamp: $ date +%s 1735689600 This…
You may need to prevent certain packages from being updated during system maintenance—the kernel on production servers, or specific library versions you’ve carefully tuned. When you run dnf update or yum update, you want those packages skipped entirely. The solution is straightforward: add an exclusion to DNF or YUM’s configuration file. Configuration Syntax Add this…
Port forwarding allows external hosts to reach services inside a private network by mapping traffic from a public address to an internal one. On Linux, this is implemented through iptables rules that modify packet headers as they traverse the kernel’s netfilter framework. Common use cases include exposing HTTP/HTTPS servers from a private LAN to the…
Compiling LaTeX documents with BibTeX involves multiple passes—typically three runs of latex followed by one bibtex run to resolve citations. This sequence is identical across most documents, making it perfect for automation with a Makefile. Basic Makefile Template Here’s a practical Makefile for LaTeX with BibTeX support: FILENAME = main LATEX = pdflatex BIBTEX =…
On Fedora/RHEL-based systems: dnf install ecryptfs-utils On Debian/Ubuntu: apt-get install ecryptfs-utils Load the kernel module modprobe ecryptfs To ensure the module loads automatically on boot, add it to /etc/modules-load.d/: echo “ecryptfs” | sudo tee /etc/modules-load.d/ecryptfs.conf Create directories You’ll need two directories: one for encrypted storage (.private) and one as the mount point (private). The .private…
If you don’t already have a key pair, use Ed25519 — it’s faster and more secure than RSA: ssh-keygen -t ed25519 -C “your_email@example.com” For older systems that don’t support Ed25519, RSA with 4096 bits still works: ssh-keygen -t rsa -b 4096 Keys are stored in ~/.ssh/ by default: id_ed25519 (private) and id_ed25519.pub (public) for Ed25519,…
sshfs is the standard tool for mounting remote filesystems over SSH. It’s available in most distribution repositories. Debian/Ubuntu: sudo apt install sshfs RHEL/CentOS/Fedora: sudo dnf install sshfs Alpine: apk add sshfs On some systems you may need to ensure the fuse kernel module is loaded: sudo modprobe fuse Basic Mount Mount a remote directory to…
The mailx (or s-nail on modern distributions) command remains useful for scripted email delivery, particularly when you need to send alerts or notifications automatically. Gmail’s SMTP service works well for this, though it requires TLS authentication and specific configuration. Prerequisites Most Linux distributions include mailx or s-nail by default. On systems using s-nail (Ubuntu 20.04+,…
A SOCKS5 proxy tunneled through SSH provides encrypted communication between your client and a remote server. This is useful for bypassing network restrictions, securing connections on untrusted networks, or routing traffic through a trusted server. Basic Setup The simplest approach uses SSH’s dynamic port forwarding with the -D flag: ssh -D 8080 username@sshd_server This creates…
Xen remains in production use (AWS EC2, Citrix Hypervisor), though KVM has become the standard Linux hypervisor. This guide covers automating backups for file-backed Xen virtual machines. The approach adapts to other hypervisors like KVM with minimal modification. Architecture and Prerequisites The backup system assumes: Virtual machines stored in /lhome/xen/ with individual directories per VM…
When you need to start long-running commands while continuing to work in the shell, run them in the background. Bash and other modern shells maintain a job list and allow you to switch jobs between foreground and background execution. Only one job can run in the foreground at a time. Starting a Background Job Append…
Accessing a remote desktop environment on a Linux server securely requires proper tunneling. While SSH X11 forwarding works for single applications, VNC provides a full graphical desktop session. By combining VNC with an SSH tunnel, you encrypt all traffic and can work around firewall restrictions that only allow port 22. Why VNC Over SSH? VNC…