This Linux kernel change addresses a memory leak in the CIFS client code where auth_key.response was not being freed during session reconnection. The fix ensures that any existing authentication key response is released before setting up a new session, preventing memory exhaustion over repeated reconnect cycles. The Problem When a CIFS mount encounters a connection…
Linux kernel 4.19.70 is a stable release containing 95 fixes and improvements across multiple subsystems. This release addresses critical issues in audio, networking, storage, virtualization, DMA handling, and various device drivers. Major Fixes Audio and Sound ALSA USB Audio Improvements The release includes several USB audio enhancements. A quirk was added for Behringer UFX1604 to…
This commit addresses a recording issue on systems using the Realtek ALC256 audio codec where headphone microphone input wasn’t functioning properly. The Problem The ALC256 codec had its default PCBeep path configured in a way that interfered with headphone microphone recording. The audio input wasn’t being routed correctly when a microphone was connected to the…
The kernel commit “fs: handle SEEK_HOLE/SEEK_DATA properly in all fs’s that define their own llseek” (06222e4) by Josef Bacik ensures that all filesystems with custom llseek implementations properly handle the SEEK_HOLE and SEEK_DATA whence values introduced in Linux 3.1. Why This Matters When a filesystem implements a custom llseek handler, it bypasses the generic implementation….
Linux is a multi-user operating system where multiple users can run processes simultaneously. Groups provide a mechanism to efficiently manage permissions for collections of users without having to set individual permissions for each account. What are user groups? A user group is a collection of user accounts that can be assigned permissions as a unit….
PNG images already use DEFLATE compression (a combination of LZ77 and Huffman coding), but you can reduce file sizes further by optimizing the PNG’s internal structure and removing metadata. OptiPNG recompresses the image data without any quality loss by trying different compression strategies and selecting the best result. Install it on Ubuntu/Debian: sudo apt install…
Each process on Linux has its own environment variable namespace. While normally isolated, there are scenarios where you might need to modify a running process’s environment—usually for debugging, testing, or dynamic configuration changes. The standard approach uses GDB’s ability to call functions within a running process. This works by attaching GDB to the target process…
Start by viewing the GRUB menu entries that will be generated during the next boot: sudo grub-mkconfig | grep -E ‘submenu |menuentry ‘ This will output something like: menuentry ‘Ubuntu’ –class ubuntu –class gnu-linux –class gnu –class os $menuentry_id_option ‘gnulinux-simple-…’ { submenu ‘Advanced options for Ubuntu’ $menuentry_id_option ‘gnulinux-advanced-…’ { menuentry ‘Ubuntu, with Linux 6.8.0-45-generic’ –class…
When you chain multiple commands with pipes or line continuations in Bash, the resulting one-liner becomes hard to read. Adding comments inline—rather than just before the entire command—makes the script self-documenting and maintainable. Inline comments with pipe-delimited commands The cleanest approach for piped commands leverages Bash’s syntax: you can place a comment after the pipe…
Perl one-liners are powerful for text processing, but by default the -p and -n options process input line by line. When you need to match patterns across multiple lines, you’ll hit limitations because \s doesn’t match newlines by default, and the record separator is set to \n. The solution is the -0777 flag, which changes…
Hyperledger Fabric is a modular, enterprise-grade consortium blockchain platform. While its official documentation is comprehensive, deploying a test network from scratch requires configuring multiple dependencies and tools—a process that’s time-consuming for new users. This guide covers both automated and manual setup approaches to get a working Fabric network running quickly. Prerequisites You’ll need: Ubuntu 24.04…
grep processes input line-by-line by design, which makes matching patterns across multiple lines challenging. However, several approaches exist to search for consecutive lines as a single block, each with different tradeoffs. The problem You need to verify that a file contains two specific consecutive lines with nothing between them. For example, checking if ~/.bashrc has:…
When you need a specific Go version on Ubuntu, the default package manager often lags behind. Production systems like Kubernetes, Hyperledger Fabric, and other projects frequently require versions newer than what’s available in standard repositories. This guide covers system-level installation that allows multiple versions to coexist. Remove existing Go installations Start by cleaning up any…
GCC applies sophisticated optimizations to recursive functions, and recursive inlining is one of the most dramatic. When the compiler can’t use simple tail-call optimization—because a function has side effects like printf that reference stack parameters—it often unrolls multiple recursion iterations into a single function body. Understanding this behavior matters for performance tuning, debugging, and predicting…
Start with the official Bash manual—it’s comprehensive and essential before writing production scripts. Access it locally with: man bash Or online at the GNU Bash Manual. The density rewards careful reading; spend time on these sections: INVOCATION: How the shell starts and behaves Quoting: When to quote and when not to Parameter Expansion: Variable manipulation,…
RHEL and CentOS 8+ ship 64-bit only by default. Some Windows applications require 32-bit Wine or run better under it. Since the distribution repositories don’t provide prebuilt 32-bit Wine, you’ll need to compile from source. The process requires building 64-bit Wine first, then 32-bit, then rebuilding 64-bit to establish proper cross-architecture linking. Install Build Dependencies…
View all virtual machines registered with VirtualBox: vboxmanage list vms Output example: “ubuntu-server” {a1b2c3d4-e5f6-7890-abcd-ef1234567890} “debian-test” {b2c3d4e5-f6a7-8901-bcde-f12345678901} “centos-prod” {d6c938d8-0bec-57f0-9fd3-8e395ba3d218} Each VM appears with its name and UUID. The UUID uniquely identifies the VM in VirtualBox’s database. List running VMs only See only active virtual machines: vboxmanage list runningvms This is useful when you have many VMs…
Gmail requires OAuth2 authentication for SMTP access — direct passwords have been disabled entirely. This is the only supported method for sending mail through Gmail in Thunderbird, whether you’re using a personal or Workspace account. OAuth2 Setup Open Thunderbird and go to Account Settings → Outgoing Server (SMTP). Click Add and configure these settings: Server…
Insync is a third-party sync client that fills the gap left by Microsoft’s lack of native Linux support for OneDrive. It handles both personal OneDrive and OneDrive for Business accounts reliably and integrates cleanly with your desktop environment. Installation Debian/Ubuntu/Linux Mint sudo apt-key adv –keyserver keyserver.ubuntu.com –recv-keys ACCAF35C sudo add-apt-repository “deb http://apt.insync.io/debian $(lsb_release -cs) non-free…
git log is your primary tool for viewing repository history. These commands work across all Git hosting platforms (GitHub, GitLab, Gitea, etc.) and are essential for debugging, code review, and maintaining audit trails. Basic commit listing git log –oneline Each commit appears as a single line with the abbreviated hash and message. Add –reverse to…