Programming languages and software development
The traditional Node.js approach uses require(). Create a module that exports functions, then import them where needed. exporting functions (math.js): function add(a, b) { return a + b; } function subtract(a, b) { return a – b; } module.exports = { add, subtract }; importing in another file (app.js): const { add, subtract } =…
Processing files line by line is a common task in Go. Here are the practical approaches, from simplest to most flexible. Using bufio.Scanner The most straightforward method uses bufio.Scanner, which handles line splitting automatically: package main import ( “bufio” “fmt” “log” “os” ) func main() { file, err := os.Open(“input.txt”) if err != nil {…
Many Go functions accept an io.Reader interface. To pass a string to these functions, use strings.NewReader, which wraps the string without copying it—the data is read directly from the original string. Basic Usage import “strings” reader := strings.NewReader(“Hello, World!”) This creates an io.Reader that can be passed to any function expecting that interface. The reader…
When you’re working in a Makefile, you often need to reference files relative to where the Makefile itself is located. This is especially useful for multi-directory projects or when your build system needs to know its own location. The Solution Make provides the MAKEFILE_LIST variable, which contains the names of all makefiles that have been…
The Windows Start Menu pulls shortcuts from two key directories. Understanding where these files live is essential if you’re managing deployments, troubleshooting pinned apps, or automating setups. User-Specific Start Menu User-scoped shortcuts go here: C:\Users\<YourUsername>\AppData\Roaming\Microsoft\Windows\Start Menu\Programs This directory contains all the Start Menu shortcuts specific to your user account. Shortcuts you create or applications install…
Modern Universal Windows Platform (UWP) apps store their data in protected user-specific directories. Understanding this structure is essential if you need to back up app settings, troubleshoot issues, or migrate data between systems. Default Data Location UWP app data lives here: C:\Users\<YourUsername>\AppData\Local\Packages\<AppPackageName>\ The <AppPackageName> is a unique identifier assigned by Windows—typically a long alphanumeric string…
iOS SSH clients have matured significantly, and if you need SOCKS proxy support, there are several solid options worth evaluating. The key difference from desktop clients is that iOS imposes sandbox restrictions, so dynamic forwarding requires apps built with that constraint in mind. vSSH vSSH remains one of the more capable SSH clients for iOS,…
SSH key management becomes critical when you’re handling multiple identities across different hosts. By default, ssh tries keys in a specific order, but you can explicitly configure which key to use for particular hosts through the SSH config file. Using ~/.ssh/config The cleanest approach is to define host-specific key configurations in ~/.ssh/config. This file lets…
Tethering your iPhone to your computer’s internet connection via USB is useful when you need a stable, low-power connection or want to avoid wireless overhead. This guide covers the practical setup on Windows and how to configure your iPhone to use your PC’s internet. Windows USB Tethering Setup On Windows 10/11: Install iTunes or Apple…
You can retrieve detailed metadata about an S3 object using the aws s3api head-object command. This is useful when you need to check object properties, sizes, modification times, or custom metadata without downloading the entire file. Basic Usage The simplest form queries an object’s metadata: aws s3api head-object –bucket test-hkust –key dir2/fileupload/fb0c6353-a90c-4522-9355-7cd16cf756ff.file.txt This returns output…
The YARN resource scheduler determines how cluster resources are allocated to jobs. By default, Hadoop uses the Capacity Scheduler, but you can switch to an alternative like the Fair Scheduler or configure different scheduling policies. Identifying Your Current Scheduler Check which scheduler is currently active by examining your configuration: grep -A 2 “yarn.resourcemanager.scheduler.class” $HADOOP_HOME/etc/hadoop/yarn-site.xml The…
If you’ve set up passwordless SSH login with key-based authentication but lftp keeps prompting for a password, you need to explicitly configure it to use your SSH keys. The basic approach The simplest method is to pass an empty password to lftp, which signals it to fall back on SSH key authentication: lftp -u user,…
Extracting a file extension from a filename is a common task. Here are the main approaches, with modern best practices. Simple Method with lastIndexOf() The most straightforward approach uses lastIndexOf() to find the last dot: function getExtension(filename) { const lastDotIndex = filename.lastIndexOf(‘.’); return (lastDotIndex < 1) ? ” : filename.substring(lastDotIndex + 1); } console.log(getExtension(‘file.txt’)); //…
Python provides several ways to check if files or directories exist, with different trade-offs depending on your use case. Using pathlib (recommended) The modern approach uses pathlib.Path, which is cleaner and more object-oriented: from pathlib import Path path = Path(‘/etc/passwd’) # Check if path exists (file or directory) if path.exists(): print(“Path exists”) # Check if…
When you initialize a new repository locally and try to push to GitHub or Bitbucket for the first time, you’ll likely encounter errors like: No refs in common and none specified; doing nothing. Perhaps you should specify a branch such as ‘master’. fatal: The remote end hung up unexpectedly This happens because your local repository…
If you need to jump to a particular byte position in a file, Vim provides the goto command. This is useful when debugging binary files, working with hex editors, or when error messages reference byte offsets. Using the goto command In normal mode, press go followed by the byte number: 20go This moves the cursor…
When you need to restrict a find-and-replace operation to a specific block of text, Vim gives you several approaches. Using the %V atom The most straightforward method is the %V atom, which restricts pattern matching to the current visual selection: :%s/%Vfrom/to/gc This works regardless of the visual mode you used (character, line, or block). The…
When renewing an SSL certificate, your CA will request a Certificate Signing Request (CSR). If you have the private key but need to generate a fresh CSR, OpenSSL handles this straightforwardly. Basic CSR Generation Generate a CSR from your existing private key: openssl req -new -key ssl.key -out req.pem This creates req.pem containing your CSR,…
To identify the developers who’ve contributed the most commits to a repository, use git log with some text processing: git log –format=’%aN’ | sort | uniq -c | sort -rn This returns a sorted list with commit counts and author names: 247 Paul Phillips 45 Dale Wijnand 12 Yamashita Yuu 10 Gilles Cornu 8 Josh…
Vim’s filetype detection usually works well, but sometimes it fails—especially with newly created files, unconventional extensions, or files without extensions. When that happens, you need to set the filetype manually. Setting Filetype in the Current Session The simplest way is to use the filetype option while Vim is open: :set filetype=php Replace php with whatever…