When network interfaces fail or behave unexpectedly, you need to inspect driver details, hardware state, and kernel messages. Here’s the practical toolkit for diagnosing network hardware and driver issues. Kernel Messages and Logs Start by checking kernel logs where driver initialization and errors are recorded: dmesg | grep -i network dmesg | grep -i driver…
When you need to identify which package installed a command on your Fedora system, you have several reliable methods depending on whether the package is already installed. Quick lookup for installed commands The fastest approach combines which to locate the command with rpm to query the owning package: $ rpm -qf $(which ping) iputils-8.40-4.fc40.x86_64 The…
Fedora upgrades are straightforward with dnf system-upgrade, the standard tool for network-based distribution upgrades. This replaces the older fedup tool and handles everything from downloading packages to managing the upgrade environment. Pre-Upgrade Checklist Before starting any upgrade: Update your current system: sudo dnf upgrade Back up critical data — especially /etc, home directories, and application…
The most reliable one-liner to count files in the current directory is: find . -maxdepth 1 -type f | wc -l This counts only regular files (not directories or symlinks) and handles edge cases that trip up simpler approaches. Why Not Use ls | wc -l? The common ls | wc -l command has several…
The @ symbol in Makefiles suppresses the echo of the command itself before execution. When you run a target, make normally prints each command to stdout before running it. Adding @ before a command hides that echo, showing only the command’s output. Basic example Without @: all: echo “For correctness test of basic get and…
If you need direct control over your firewall rules, you can disable firewalld and use iptables instead. This guide covers the setup process and best practices for maintaining persistent rules. Stop and disable firewalld If firewalld is currently running, stop it and prevent it from starting on boot: sudo systemctl stop firewalld sudo systemctl disable…
Fedora uses FirewallD as its default firewall management service. If you’re running servers in a trusted internal cluster or isolated environment where network-level filtering isn’t needed, you can disable it entirely. Stop and Disable FirewallD To completely disable the firewall: sudo systemctl stop firewalld sudo systemctl disable firewalld The stop command halts the service immediately….
When your HP printer runs out of paper mid-job on Linux, the print queue pauses and won’t resume automatically once you reload paper. You need to either clear the error state physically or use CUPS commands to resume printing. Physical Reset Method The quickest approach for most HP printers is to trigger the paper-detect sensor:…
Exit codes are how programs communicate success or failure to the shell and parent processes. Understanding them is essential for writing reliable scripts and debugging applications. Linux and Windows handle these differently, so knowing both conventions matters if you work across platforms. Linux Exit Codes On Linux, the convention is simple: 0 means success, 1–255…
When you need to download large files faster, parallelizing across multiple connections can significantly improve throughput. Standard tools like wget and curl use single connections by default, but several alternatives support multi-connection downloads that can achieve 3-5x speedups on capable networks. aria2c aria2 is the most powerful option. It handles HTTP, HTTPS, FTP, BitTorrent, and…
Parsing directory and filename components from an absolute path is a common task in systems programming. Linux provides dirname() and basename() functions for this purpose, but they have implementation-specific behaviors that can cause bugs if you’re not careful. Using dirname() and basename() The POSIX standard defines both functions, though the implementations vary. Here’s the safest…
When converting PostScript to PDF using ps2pdf with certain PDFSETTINGS options, you may hit this error: GPL Ghostscript 9.10: Set UseCIEColor for UseDeviceIndependentColor to work properly. Unrecoverable error: stackunderflow in .setdistillerparams This occurs when Ghostscript’s internal stack runs out of expected values during PDF distiller parameter processing. The root cause is usually conflicting color space…
The lp command is the standard tool for printing from the Linux command line. It interfaces with CUPS (Common Unix Printing System), the printing backbone on virtually all modern Linux distributions. Basic Printing Send a file to your default printer: lp text-file.txt Specify a particular printer: lp -d printer-name text-file.txt List available printers and identify…
The nl command is purpose-built for adding line numbers to text files: nl text-file By default, nl numbers all non-empty lines and skips blank lines. This behavior is controlled by the body section style, which defaults to t (text only). Common nl options Number all lines including blanks: nl -ba text-file Start numbering at a…
Bash doesn’t have a goto statement, and that’s intentional. The language is designed to encourage cleaner control flow patterns that are easier to debug and maintain. When you feel the urge to jump around in your script, there’s almost always a better approach. Functions and Early Return The cleanest pattern is extracting logic into functions…
Thunderbird stores message filters in per-account configuration files, making it inconvenient to replicate filters across multiple accounts or installations. Rather than recreating filters manually, you can copy filter files directly or use symbolic links to keep filters synchronized. Where Thunderbird Stores Filters Thunderbird saves filter rules in msgFilterRules.dat, a plain text configuration file. Each account…
Line number displays in Emacs can feel cramped without proper spacing. Modern Emacs provides built-in control over line number formatting and width—no external packages needed. Using display-line-numbers-mode display-line-numbers-mode is the standard in Emacs 25+ and should be your default choice. It’s faster and more maintainable than the older linum-mode. Enable it globally: (global-display-line-numbers-mode t) To…
If xterm displays Chinese, Japanese, or Korean characters as empty boxes or rectangles, the problem is almost always a missing or improperly configured font with CJK glyphs. Configure fonts in ~/.Xresources xterm reads font configuration from ~/.Xresources. Add these lines: XTerm*utf8: 1 XTerm*locale: true XTerm*faceName: Noto Mono XTerm*faceSize: 11 XTerm*faceNameDoublesize: Noto Mono XTerm*dynamicColors: true The…
Emacs startup time matters when you’re opening files frequently from the command line or in scripts. A few targeted optimizations can reduce perceived startup overhead from seconds to near-instant. Run Emacs as a daemon with emacsclient The most effective optimization is the server/client architecture. Start Emacs once as a daemon, then reuse that instance for…
Backing up a complete IMAP account with thousands of messages across nested folders requires automation to preserve folder structure and avoid manual errors. This guide covers three modern tools and provides detailed setup for the most flexible option. Choosing your backup tool offlineimap — Most flexible for complex folder structures and label handling. Active maintenance…