When backing up with rsync, you often need to skip directories like cache/, node_modules/, or .git/ that appear at multiple levels in your directory tree. Listing every instance individually is impractical, but rsync’s exclude patterns handle this elegantly. Basic exclude syntax The simplest approach uses –exclude with a directory name pattern: rsync -avxP –exclude=cache/ /path/to/src/directory/…
When you need to audit disk usage or understand directory structure, counting files in each subdirectory is a common task. This is especially useful when dealing with large directory trees where you need a quick overview of distribution. The Basic Approach The simplest method uses a loop with find and wc: for i in */;…
When you create a new branch locally and try to git pull, you’ll hit this error if the branch doesn’t have upstream tracking configured: You asked me to pull without telling me which branch you want to merge with, and ‘branch.dev-harry.merge’ in your configuration file does not tell me, either. This happens because Git doesn’t…
When you run cat /etc/resolv.conf on a modern Linux system, you’ll often see nameserver 127.0.0.1 or 127.0.1.1 pointing to localhost. This doesn’t mean you’re actually using your ISP’s DNS directly — it usually means your system is running a local DNS stub resolver or caching service like systemd-resolved or dnsmasq. To find out which actual…
A USB drive that’s mounted as read-only is frustrating — you can read files but can’t write, delete, or modify anything. This usually happens due to filesystem issues, hardware problems, or missing drivers. Check the Current State First, identify how the drive is mounted and what filesystem it uses: lsblk -f Look for your USB…
MPlayer is largely unmaintained as of 2026. For playing 3D movies on standard displays, mpv is the modern replacement and offers better stereo rendering support. Using mpv for 3D Playback The most straightforward approach with mpv is to use the stereo3d filter to convert side-by-side or other 3D formats to anaglyph (color-separated) stereo: mpv –vf=stereo3d=sbsl:arced…
fdisk -l displays partition information in sectors by default, which isn’t practical for most sysadmin tasks. While fdisk itself lacks options to change the unit display, parted shows partition sizes in GB/MB/KB automatically and is the better tool for this job. Using parted for readable partition output Run parted with the -l flag to list…
Spark SQL doesn’t have a separate DDL/DML specification distinct from Hive QL — it inherits its SQL dialect directly from Hive. If you’re designing a SQL engine or looking to understand Spark SQL’s data definition and manipulation capabilities, you need to reference Hive’s DDL and DML documentation. Why Spark SQL Uses Hive QL Spark SQL…
A sequence point is a point in execution where all side effects from previous evaluations are guaranteed to be complete and visible. Understanding sequence points is critical for writing correct C code, especially when dealing with expressions that modify variables. The C standard defines side effects as changes to the state of the execution environment…
When you need to change the commit message of a past commit that isn’t HEAD, git commit –amend alone won’t help. You’ll need to use interactive rebase to stop at that commit, amend it, and then continue. Interactive Rebase to Edit a Commit The core approach is git rebase -i with the commit hash. Say…
Linux Mint’s Cinnamon desktop automatically mounts removable media like USB drives and external hard drives by default. If you prefer manual control over when and how storage devices are mounted, you can disable this behavior through Nemo, the Cinnamon file manager. Disable Auto-Mounting via Nemo Preferences The simplest approach is to configure Nemo’s mounting behavior…
If you’re running Google AdSense on your site, you might want to show ads only to desktop visitors and hide them on mobile devices. This reduces clutter on smaller screens and can sometimes improve user experience—though test your bounce rates to confirm it actually helps your metrics. Using CSS Media Queries The cleanest approach is…
Attaching storage to a running Xen DomU without rebooting is straightforward using the xl toolstack. This is useful when you need to add capacity, attach backup storage, or provision new volumes without downtime. Basic Disk Attachment To attach a logical volume or physical disk to a running DomU, use xl block-attach on Dom0: xl block-attach…
A database schema is the blueprint that defines how data is organized and stored in a database. Think of it as the architectural plan for your database—it specifies tables, columns, data types, relationships, constraints, and rules that govern how data can be stored and accessed. Core Components of a Schema A schema encompasses several key…
When working with codebases that use non-standard file extensions for C source files, ctags won’t recognize them by default. You can configure it to treat files with custom extensions like .c0 or .puc as C source code. Using the langmap option The simplest approach is to add language mappings to your ctags configuration. Edit ~/.ctags…
Vim determines file types by extension to apply syntax highlighting and indentation. If you have custom file extensions that should be treated as C files, you need to configure Vim to recognize them. Using autocommand in .vimrc Add an autocommand to your ~/.vimrc: ” Treat .h and .c files in a custom directory as C…
GIMP is the most full-featured image editor on Linux, but it can be overkill for quick edits. Several lighter alternatives provide essential editing features without the complexity or resource usage of GIMP. Pinta — Simple Paint.NET-Style Editor sudo dnf install pinta # Fedora sudo apt install pinta # Ubuntu Pinta provides a clean interface with…
When managing a Linux system remotely, you sometimes need to terminate all sessions for a specific user—whether they’re logged in locally at the console, via SSH, through X11 forwarding, VNC, or any other method. Here’s how to do it. Quick Answer To terminate all processes for a user named bob: killall -u bob This kills…
When your iPhone completely freezes or becomes unresponsive, a force restart is usually the fastest way to get it working again. Unlike a regular restart, a force restart bypasses the normal shutdown process and forces the device to reboot immediately. Force Restart by iPhone Model The method depends on which iPhone you have. Apple changed…
When running make recursively with $(MAKE) or make -C, you’ll see verbose messages like “Entering directory” and “Leaving directory” for each subdirectory. These messages clutter the build output and make it harder to spot actual errors. The Quick Fix Pass –no-print-directory to make: make –no-print-directory Or set it in your Makefile: .MAKEFLAGS: –no-print-directory Suppressing via…