When writing C programs on Linux that handle file paths, you need to allocate buffers safely. The kernel defines maximum path and filename lengths through standard macros in <linux/limits.h>. Getting the limits On Linux systems, <linux/limits.h> provides two key macros: NAME_MAX — maximum length of a single filename component (255 characters) PATH_MAX — maximum length…
When you have a password-protected RSA private key (indicated by the Proc-Type: 4,ENCRYPTED header), you’ll need to decrypt it before using it with most applications. The openssl command handles this straightforwardly. Basic decryption Use openssl rsa to decrypt the key: openssl rsa -in encrypted_key.pem -out decrypted_key.pem You’ll be prompted to enter the password for the…
By default, Git doesn’t automatically configure your local branch to track its remote counterpart. You need to explicitly set up this tracking relationship so that git pull and git push know which remote branch to synchronize with. Setting Up Tracking for an Existing Branch If you already have a local branch and want it to…
Cinnamon on Fedora offers solid theming options through the official repositories. Here’s a practical approach to building a cohesive desktop environment with matching window borders, icons, controls, and cursor themes. Installing Theme Packages Start by installing available theme packages from the Fedora and Cinnamon repositories: sudo dnf install cinnamon-themes cinnamon-control-center sudo dnf install papirus-icon-theme adwaita-icon-theme…
When you try to redirect output from a sudo command to a file using >, you’ll hit a permission error: $ sudo echo “echo hello” > /usr/local/bin/hello bash: /usr/local/bin/hello: Permission denied This happens because the shell processes the redirection operator > before sudo runs. The redirection happens in your unprivileged shell context, not as root….
Forcing HTTPS on your website protects visitor data and improves SEO. The most common method is using .htaccess with Apache’s mod_rewrite module to redirect all HTTP requests to HTTPS. Basic HTTPS redirect Add this to your .htaccess file in the document root: RewriteEngine On RewriteCond %{HTTPS} !=on RewriteRule ^ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301] This performs a permanent…
If you need to scan documents on Windows, several solid open-source options exist. Here are the most practical choices. NAPS2 (Not Another PDF Scanner 2) NAPS2 remains the top recommendation for Windows scanning. It’s straightforward, actively maintained, and handles most scanner hardware without headaches. What it does: Scans from WIA and TWAIN-compatible scanners Saves to…
When a hard drive fails physically, data recovery becomes challenging but sometimes possible. If the drive isn’t recognized by the system or showing signs of mechanical failure, professional recovery services may be necessary—but they’re expensive. Before going that route, you can attempt recovery yourself using open-source tools. When to attempt DIY recovery You can safely…
GNU Screen is a terminal multiplexer that lets you manage multiple shell sessions within a single window. If you’re new to it, here are the best resources to get up to speed, plus practical tips for getting started. Getting Started with Screen For an introduction to the basics, start with A quick tutorial on screen….
Connecting your application to a MySQL database is fundamental to most backend systems. Rather than shelling out to the mysql command-line client, you’ll use language-specific connectors that provide proper connection pooling, error handling, and prepared statements. Language-Specific MySQL Drivers The best approach depends on your tech stack: Python Use mysql-connector-python for straightforward connections or PyMySQL…
Managing a cluster of servers, you’ll want to be notified when they come back online after restarts or unexpected reboots. Email notifications on boot let you track infrastructure changes and catch potential issues early. Using crontab @reboot The simplest approach is a crontab @reboot entry that runs once at startup. This executes before most services…
The core problem here is legitimate: if you’re running multiple jobs on the same dataset where the mapper phase produces identical intermediate results, recomputing those results is wasteful. However, skipping the mapper phase entirely breaks MapReduce’s processing model. There are better approaches. Why You Can’t Just Skip the Mapper MapReduce assumes data flows through map…
The standard crontab -e command opens an interactive editor, which doesn’t work in automated scripts. To add crontab entries non-interactively, you need to pipe a list of cron jobs directly to crontab -. Basic approach The simplest method reads the existing crontab, appends your new entry, and writes it back: (crontab -l 2>/dev/null; echo “@reboot…
HDFS doesn’t natively support directory-level replication factor inheritance. Even if you set a specific replication factor on a directory and its files, new files created in that directory will default to the cluster’s global dfs.replication setting (typically 3). This limitation can complicate multi-tier storage strategies where you want temporary or low-priority data on fewer replicas…
Finding files that match a pattern is straightforward with ls *string* or find . -name ‘*string*’. But excluding files with a certain string in their filename requires a different approach. Using find with negation The most reliable method is find with the ! (or -not) operator: find . -type f ! -name ‘*string*’ This finds…
RPM Fusion provides packages that Fedora and RHEL can’t ship by default due to patent, licensing, or trademark restrictions. This includes multimedia codecs, proprietary drivers, and other software. Here’s how to enable it on RHEL 9 and Rocky Linux. Enable RPM Fusion Free and Non-Free # Enable EPEL first (required dependency) sudo dnf install epel-release…
The sed stream editor is the go-to tool for deleting lines from files in Linux. It’s fast, works on large files without loading everything into memory, and handles complex patterns easily. Delete a Single Line by Line Number To delete the 4th line from a file: sed -i ‘4d’ ./file The -i flag edits the…
Fedora’s default repositories don’t include musl libc, but you have two practical options: install it from a community repository if available, or build from source. Building from source gives you full control and is the most reliable approach across Fedora versions. Option 1: Build from Source (Recommended) Start by installing the build dependencies: sudo dnf…
Converting between Simplified Chinese (SC) and Traditional Chinese (TC) characters on Linux is straightforward with OpenCC, a mature open-source tool designed specifically for this task. Installing OpenCC Most distributions include OpenCC in their standard repositories: # Debian/Ubuntu sudo apt install opencc # RHEL/CentOS/Fedora sudo dnf install opencc # Arch sudo pacman -S opencc Alternatively, build…
Merging branches is one of the most common Git workflows. The basic process is straightforward, but understanding the different merge strategies and when to use them prevents silent mistakes and keeps your history clean. The Basic Merge Flow To merge a feature branch into another branch: git checkout rc git merge dev-harry This checks out…