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Automating keyboard input on Linux is useful for testing, accessibility workflows, and automation scripts. If you need to simulate pressing multiple keys simultaneously and holding them, xdotool is the standard tool for this job. Basic approach with xdotool The keydown and keyup commands let you press and release individual keys without triggering the other. To…
When you’re processing text with varying amounts of whitespace between fields, the standard cut command falls short. Given input like this: a b c d You need a way to reliably extract fields regardless of how many spaces separate them. Here are the practical approaches. Using tr with cut The tr command can normalize whitespace…
Sending POST requests from client-side JavaScript is a common task, and you have several modern options. The approach you choose depends on your project’s dependencies and browser support requirements. Fetch API (Recommended for Modern Projects) The Fetch API is the modern standard and requires no external library. It’s built into all current browsers and handles…
The window.open() method is the standard way to open URLs in a new browser window or tab. Here’s how to use it effectively in modern JavaScript. Basic Usage To open a URL in a new window or tab: const url = “https://www.systutorials.com”; window.open(url); Most modern browsers will open this in a new tab by default,…
Getting a file’s size is a common task in Python. There are several ways to do it, depending on what you need and how much detail you want about the file. Using os.path.getsize() The simplest approach is os.path.getsize(): import os file_path = ‘/path/to/your/file.txt’ size_bytes = os.path.getsize(file_path) print(f”File size: {size_bytes} bytes”) This returns the size in…
When uploading files to HDFS using hdfs dfs -put, the replication factor defaults to the cluster-wide setting in hdfs-site.xml (typically 3). For temporary files, logs, or staging data, you often want a lower replication factor to reduce write latency and disk usage. Override Replication Factor at Upload Time Use the -D flag to pass HDFS…
When you need to traverse a directory tree in Python, you have several options. The choice depends on whether you want recursive traversal, how you want to handle the results, and your Python version. Using os.walk() The os.walk() function is the classic approach for recursively iterating through directories. It yields tuples of (dirpath, dirnames, filenames)…
The most reliable way to get a file extension in Python is os.path.splitext(), which splits a filename into the base name and extension. For modern code, pathlib.Path provides a cleaner alternative. Using os.path.splitext() os.path.splitext() returns a tuple of (name, extension): import os name, ext = os.path.splitext(‘file.txt’) print(name) # ‘file’ print(ext) # ‘.txt’ This works with…
When handling POST requests in Node.js, you need to read the incoming data stream and parse it. The approach varies depending on whether you’re using raw Node.js http module, Express, or another framework. Using Express (Recommended) Express handles POST parsing automatically with built-in middleware. This is the standard approach for most modern Node.js applications: const…
The URL hash — the fragment identifier after the # — serves several purposes: in-page navigation, client-side routing, and preserving application state. JavaScript provides straightforward APIs to read and monitor hash changes. Reading the Current Hash Access the hash using window.location.hash: const hash = window.location.hash; console.log(hash); // e.g., “#section-about” This returns the hash including the…
When your Node.js application encounters a fatal error or needs to terminate, you need a reliable way to shut it down. Understanding how to exit gracefully—or forcefully when necessary—is essential for production applications. Using process.exit() The most direct method is process.exit(), which immediately terminates the Node.js process: process.exit(); This is a global method that doesn’t…
When you have SSH key-based authentication set up, the client will prefer it by default. This can make it difficult to test whether password authentication is working—especially after changing a password or troubleshooting login issues. Force password-only authentication Use the -o PreferredAuthentications=password flag: ssh -o PreferredAuthentications=password username@host This tells SSH to use password authentication exclusively,…
The simplest way to detect whether your Linux system booted in UEFI or BIOS (Legacy) mode is to check for the existence of the EFI firmware directory. Check for EFI Directory The /sys/firmware/efi/ directory only exists when the system has booted in UEFI mode. If it’s absent, the system is running in BIOS/Legacy mode. […
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…
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…
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…
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”…