The scp command handles multiple files efficiently, whether you’re pushing to a remote server or pulling from one. Here are the practical approaches for copying multiple files from remote to local. Brace Expansion Use brace expansion to specify discrete files: scp user@remote:file{1,2,3} ./ This works well when you have a known set of files with…
When writing system administration scripts, you often need to check if a user account exists before taking action. There are several reliable methods to accomplish this. Using id command The id command retrieves user information and returns a non-zero exit code if the user doesn’t exist. This makes it ideal for conditional testing: user=”hello” if…
MATE Desktop provides a traditional GNOME 2-style interface that many users prefer over modern GNOME Shell. Here’s how to install it on Linux Mint 17 Qiana. Install MATE Desktop sudo apt-get update sudo apt-get install mate-desktop-environment For the full MATE experience with extras: sudo apt-get install mate-desktop-environment-extras This adds additional applets, themes, and utilities not…
The tilde expansion ~username works fine when the username is literal, but fails when the username is stored in a variable like ~$user. Bash doesn’t perform tilde expansion on variables by default—it only expands ~ at the beginning of a word before variable expansion happens. Using eval The most common approach is to use eval:…
Sorting text file lines by their length is useful for analyzing text patterns, finding anomalies, or preparing data for processing. Here are the most practical approaches. Using awk with sort The standard approach combines awk to calculate line length with sort to order them: awk ‘{ print length(), $0 | “sort -n” }’ /path/to/text/file This…
When you run journalctl without options on a system with years of log history, it can take seconds or even minutes to parse everything. The slowness comes from journalctl loading and deserializing potentially gigabytes of journal data. The solution is targeted querying — you almost never need the entire journal, so restrict what journalctl reads…
mpv is a powerful media player for Linux that supports looping videos with minimal configuration. Here’s how to loop videos in fullscreen mode using mpv. Loop a Single Video The simplest way — use the –loop flag: mpv –fullscreen –loop video.mp4 –loop replays the video infinitely. To loop a specific number of times: # Loop…
Bash provides several straightforward ways to test whether a string contains a substring. The best approach depends on your use case and performance requirements. Using [[ ]] with glob patterns The fastest and most Bash-native method is the [[ conditional construct with glob patterns: if [[ “$string” == *”substring”* ]]; then echo “Found it!” fi…
LevelDB allows key ranges to overlap across SSTables in Level 0, unlike higher levels where overlaps are eliminated through compaction. This design choice is fundamental to LevelDB’s write performance and is worth understanding in detail. Why Level 0 Allows Overlaps The reason comes down to write efficiency. When you write data to LevelDB, it follows…
By default, xargs appends its input as arguments at the end of the command. This works fine when you need a utility once per item, but becomes problematic when you need to reference the same input multiple times in different positions. The Problem Consider renaming files by appending .bak to each filename. You might try:…
Monitoring directory growth is essential for tracking logs, temporary files, and catching runaway disk usage before it becomes a problem. Linux offers several approaches depending on whether you need simple periodic checks, interactive exploration, or event-driven monitoring. Simple periodic monitoring The watch command repeatedly runs a command at set intervals: watch -n 1 du -sh…
RealVNC’s free tier is limited to personal use and restricts advanced features, making it unsuitable for many production or semi-commercial scenarios. If you need a fully-functional open-source alternative, several solid options exist. TightVNC TightVNC remains a reliable choice for Windows VNC hosting. It’s GPL-licensed, fully open-source, and includes both server and client components. Installation: Download…
The git diff –word-diff output is clean and readable for tracking changes at the word level instead of line-by-line. If you need that functionality outside a git repository—or just want a standalone tool—wdiff is purpose-built for exactly this. Using wdiff for word-level diffs wdiff compares two files word by word, where a word is defined…
The free command—along with ps, top, kill, pgrep, and dozens of other system utilities—is maintained as part of the procps-ng project. Source repository The source code is hosted at: https://gitlab.com/procps-ng/procps You can clone it with: git clone https://gitlab.com/procps-ng/procps.git cd procps Most distributions package procps-ng, so you likely already have it installed. You can verify the…
Serializing objects to JSON is a fundamental task in Node.js for APIs, databases, and file storage. The approach depends on your object complexity and performance requirements. Basic Conversion with JSON.stringify The standard approach uses the built-in JSON.stringify() method: const myObject = { name: ‘John’, age: 30, email: ‘john@example.com’ }; const jsonString = JSON.stringify(myObject, null, 2);…
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…
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 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)…
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…