If you need to restart GNOME while keeping your applications open, you have several options depending on your GNOME version and setup. Quick restart with Alt+F2 The fastest method is to use GNOME’s run dialog: Press Alt + F2 Type r and press Enter This restarts the GNOME shell while preserving your running applications and…
Fedora uses RPM packages managed by DNF, but you’ll occasionally encounter software distributed only as .deb files (Debian format). You have several options: convert the .deb to RPM, extract and repackage it, or use containerization. Here’s what works in practice. Using alien to convert .deb to RPM The simplest approach is alien, a tool designed…
When managing many systems, manually confirming host keys for each new connection gets tedious fast. You can configure SSH to automatically add unknown hosts to ~/.ssh/known_hosts without prompting. The Risk Trade-off Before implementing this, understand what you’re doing: disabling strict host key checking opens you to man-in-the-middle attacks. Only use this in trusted networks where…
When you’re editing code in Vim and press Enter after a comment line, Vim automatically continues the comment on the next line. This is useful sometimes, but often gets in the way. Here’s how to disable it. The Basic Approach Add this to your ~/.vimrc: au FileType c,cpp setlocal comments-=:// comments+=f:// This works by: comments-=://…
Archiving or copying a 1TB sparse file containing only 32MB of actual data is impractical with naive approaches—you’ll waste time and I/O bandwidth copying zeros. The solution is using SEEK_HOLE and SEEK_DATA flags with lseek(), which allow tools to skip over hole regions entirely. How SEEK_HOLE and SEEK_DATA work The Linux kernel provides two additional…
Before encoding instructions, you need to understand the two assembly syntaxes you’ll encounter—they differ fundamentally in operand order and addressing format. Intel syntax (Intel/AMD manuals): Operand order: destination, source Memory addressing: [base+offset] Example: add r8, [rdi+0xa] AT&T syntax (GNU toolchains on Linux): Operand order: source, destination Memory addressing: offset(%base) Example: addq 0xa(%rdi), %r8 For most…
Most popular task monitoring tools (top, iotop, procfs) sample disk I/O information at granularity limited by kernel timer frequency—typically once per second. This sampling rate misses short-lived I/O bursts and makes it difficult to accurately measure which tasks are truly I/O bound. eBPF and kernel tracepoints let you capture microsecond-level accuracy without heavy overhead. Why…
vimtutor is the most practical way to learn Vim. It’s an interactive lesson built directly into your editor that teaches through practice rather than passive reading. You launch it from the terminal with no setup required, and you get immediate feedback on every command you type. Running vimtutor From any terminal: vimtutor This opens an…
Filtering a dependent lookup field based on another lookup field’s value is a core requirement in Dynamics 365 and Power Apps. The classic example: a Lead entity with Branch and Sub Branch fields where Sub Branch options should only display records matching the selected Branch. The form editor handles this natively—no plugins or JavaScript required….
Running commands across multiple servers is fundamental to cluster management and infrastructure automation. While orchestration tools like Ansible and Terraform dominate modern deployments, sometimes you need lightweight solutions that work without dependencies—or you’re already invested in SSH-based infrastructure. When managing clusters, you typically work in two modes: serial execution (one node at a time) and…
When verifying file integrity on Linux, you’ll typically reach for one of several checksum utilities. A natural question: which one is fastest? The answer depends heavily on whether I/O or CPU is your bottleneck. Disk I/O Dominates on Most Systems In realistic scenarios with typical storage, disk I/O is almost always the limiting factor. Test…
Watching for filesystem changes and triggering actions is essential for development workflows—recompiling after source edits, restarting services when configs update, or running tests during coding. Linux’s inotify subsystem provides kernel-level file monitoring, and inotifywait makes it accessible from the command line. Installation Install inotify-tools on your system: Fedora/RHEL/CentOS: sudo dnf install inotify-tools Debian/Ubuntu: sudo apt…
When you repurpose disks from one RAID array to another system, Linux keeps the old RAID metadata intact as a safety measure. This prevents accidental data corruption, but it also blocks you from reusing the disk until the signatures are cleared. RAID metadata isn’t stored in one place — it’s scattered across the disk by…
When SSH fails but the daemon still runs, or when kernel panics strike, you need automated recovery without physical access. This guide covers three essential techniques: forcing reboots when the system is unresponsive, auto-recovery from kernel panics, and alerting you when it happens. Force a reboot when SSH is unresponsive If a server stops responding…
The Linux kernel handles video mode configuration through bootloader parameters and kernel graphics drivers. Modern UEFI systems use Kernel Mode Setting (KMS) automatically, but you can override modes when needed. Legacy BIOS systems still use older mechanisms if you’re maintaining older hardware. UEFI Systems: Modern Video Mode Configuration On UEFI systems with GRUB2, add video…
Hadoop 2.x reached end-of-life in 2016. This guide covers setup for learning purposes and legacy system maintenance only. For production deployments, use Hadoop 3.x or later, which includes performance improvements, better YARN scheduling, HDFS erasure coding, and improved security. Cloud-managed options like AWS EMR, Google Dataproc, and Azure HDInsight eliminate most operational overhead. This guide…
git merge and git rebase both integrate changes from one branch into another, but they handle history differently. Merge creates a new commit that ties together the histories of both branches. Your feature branch history remains intact, and the main branch gains a merge commit. This is safer for shared branches because it doesn’t rewrite…
Sending email notifications when commits are pushed to a central Git repository helps teams stay coordinated and maintains audit trails. This is handled through Git hooks—scripts triggered by repository events. How Post-Receive Hooks Work When a client pushes to your Git server, the post-receive hook executes automatically. This hook lives at GIT_DIR/hooks/post-receive in your bare…
Resource management and error handling are critical in systems programming. RAII (Resource Acquisition Is Initialization) originated in C++ and ties resource lifecycles to object scope, with destructors automatically cleaning up resources. C lacks destructors and exceptions, but you can achieve similar semantics using established patterns that are battle-tested in production systems. The goto-based cleanup pattern…
Static linking embeds all library code directly into your binary. On Linux, this sounds straightforward but glibc introduces complications that pure static binaries don’t truly exist — the C library still loads dynamic features at runtime like NSS (Name Service Switch), locale data, and character set converters. Understanding these constraints is essential before committing to…