While BIOS settings are the preferred way to disable USB 3.0, you can also force USB 2.0 mode on a running Linux system by manipulating the xHCI controller’s port routing register directly using setpci. How it works Intel xHCI controllers use the XUSB2PR (xHC USB 2.0 Port Routing Register) at offset 0xd0. Setting this register…
When running tree across multiple servers or sharing output with teammates, you’ll notice the formatting can vary significantly. Some systems display box-drawing characters while others use ASCII pipes and dashes, making diff comparisons and documentation inconsistent. Understanding the Charset Differences The tree command respects the system’s locale and character encoding settings. By default, it will…
SSD performance varies significantly based on drive model, interface (NVMe vs SATA), and workload characteristics. Understanding how to benchmark your drives is more useful than memorizing typical specs—here’s how to measure actual throughput on your hardware. Basic Throughput Testing with dd The dd utility is the simplest way to measure sequential I/O performance. Here’s a…
The git status command shows repository state visually, but when you need to detect it programmatically in bash — say, to fail a CI pipeline or prevent deployments — you need a different approach. Quick Method: Check Unstaged Changes The most reliable way to detect uncommitted changes is with git diff: if [[ -n $(git…
When working with file I/O in C on Linux, you’ll often need to convert between low-level file descriptors (returned by open(), socket(), etc.) and higher-level FILE pointers (returned by fopen()). This is common when integrating different libraries or mixing POSIX I/O with standard C I/O. Getting a FILE Pointer from a File Descriptor Use fdopen()…
gThumb’s preferences aren’t always obvious when you’re looking through the traditional menu bar. The location depends on your desktop environment and gThumb version. GNOME Desktop On GNOME 3 and later, preferences are accessed through the application menu rather than the window menu: Open gThumb Click the hamburger menu (☰) in the top-right corner of the…
When you need the commit hash of the latest commit, there are several ways to get it. The most direct approach is using git log with format options rather than parsing output with grep. Using git log with –format The cleanest method is to use git log with the –format option: git log -1 –format=”%H”…
When clients connect to your OpenWRT router via DHCP, they typically receive the router itself as the default gateway. Sometimes you need to advertise a different gateway — whether you’re running a proxy, load balancer, or multi-gateway setup on your network. This is done via DHCP option 3 (the router option in the DHCP specification)….
Chrome stores passwords encrypted in the system keyring (GNOME Keyring, KWallet, or Pass depending on your desktop environment). To export them in plain text, you’ll need to create a temporary Chrome profile with basic (unencrypted) password storage, sync your passwords from Google Cloud, then extract them from the SQLite database. Prerequisites Chrome or Chromium installed…
Once your HP printer is working on a Linux system, enabling the scanner requires installing SANE (Scanner Access Now Easy) and HP-specific backends. If wireless connectivity is already established for printing, the scanner should be discoverable on the same network. Install Required Packages On Fedora: sudo dnf install sane-backends sane-backends-devel hplip hplip-common On Ubuntu/Debian: sudo…
Finding reliable, free image hosting is essential for developers, bloggers, and content creators. Your choice depends on your use case — whether you need temporary sharing, permanent hosting with transformations, or stock imagery. Imgur Imgur remains the straightforward choice for quick image sharing and temporary hosting. You can upload without an account, get an instant…
When troubleshooting email delivery or verifying mail server configuration, you need to look up the MX (Mail Exchange) records for a domain. On Linux, two tools handle this: host and dig. Both are reliable, though dig is generally preferred for its flexibility and cleaner output format. Using dig to query MX records The dig command…
Virtual hosts allow you to serve multiple websites from a single Apache server and IP address. This is the standard approach for shared hosting and cost-effective server deployments. Basic Virtual Host Setup The foundation of multi-site hosting on Apache is the VirtualHost directive. Each domain needs its own block that specifies where its files live…
The AllowOverride directive controls whether Apache will process .htaccess files in a given directory. By default, many Apache installations disable this for security and performance reasons, so you need to explicitly enable it. Enable AllowOverride for a directory Add a <Directory> block to your Apache configuration file (typically /etc/apache2/apache2.conf, a file in /etc/apache2/sites-available/, or /etc/apache2/conf-available/):…
When an NFS server goes down or becomes unreachable, client mounts can end up in a “Stale NFS file handle” state. Standard umount and umount -f commands fail, leaving you stuck with an unusable mount point and no clean way to recover without rebooting. The solution is to use umount -l (lazy unmount), which immediately…
When you need writes to one or more files to automatically go to another file, you have several options depending on your exact use case. The most common scenario is capturing output from commands, monitoring file changes, or duplicating writes across multiple destinations. Using tee for Command Output Duplication The tee command duplicates standard input…
The nomodeset parameter disables kernel mode setting (KMS), which is useful when you’re experiencing GPU-related boot issues or using older graphics hardware that isn’t properly supported by the kernel’s modeset driver. Here’s how to add it permanently to GRUB2. Edit the GRUB configuration file GRUB2 generates its active configuration from /etc/default/grub. Open this file with…
Firefox uses a profile system to isolate settings, extensions, bookmarks, and browsing data. By default, Firefox only allows one instance per profile to run at a time—new instances redirect to the existing process. If you need multiple Firefox windows with different profiles open at once, you need to disable this behavior. The -no-remote Flag The…
When working with text files containing long lines, you often need to reformat them to fit within a specific column width—typically 80 characters for readability or compatibility. Linux provides several utilities to handle this, with fold being the most straightforward option. Using fold The fold command breaks lines to fit a specified width without requiring…
Skype periodically fails to start with a “system is unavailable” error when it can’t read or write to the user’s temporary directory. This typically happens when the temp folder becomes corrupted, has permission issues, or contains orphaned Skype cache files that prevent proper initialization. Understand the Problem On Windows, each user account has a temporary…