The date command is your primary tool for retrieving Unix epoch timestamps. It’s available on virtually all Unix-like systems and integrates seamlessly into scripts and command pipelines. Basic Epoch Timestamp date +%s This returns the number of seconds since January 1, 1970 UTC. Output looks like 1735689600. Higher Precision with Nanoseconds For microsecond or nanosecond…
Environment variables are essential for configuration management—API keys, database URLs, feature flags, and environment-specific settings should never be hardcoded. Python provides straightforward mechanisms to access them. The os Module The standard way to read environment variables is with the os module: import os api_key = os.environ[‘API_KEY’] This raises a KeyError if the variable doesn’t exist….
The most straightforward way to convert SVG files to PNG is using ImageMagick or Inkscape. Both are widely available in standard repositories and handle the conversion reliably. Using ImageMagick (convert/magick) ImageMagick provides the magick command (the modern equivalent to the older convert utility): magick input.svg output.png For basic conversions, that’s all you need. To control…
The most straightforward way to read an environment variable in Python is with os.getenv(): import os api_key = os.getenv(‘API_KEY’) print(api_key) If the variable doesn’t exist, getenv() returns None. You can provide a default value as a fallback: debug_mode = os.getenv(‘DEBUG’, ‘False’) port = os.getenv(‘PORT’, ‘8000’) For variables that must exist, use os.environ[] instead. This raises…
Use os.Getenv() to read an environment variable: package main import ( “fmt” “os” ) func main() { val := os.Getenv(“MY_VAR”) fmt.Println(val) } os.Getenv() returns an empty string if the variable doesn’t exist. This means you can’t distinguish between an unset variable and one explicitly set to an empty string. Checking if a variable exists To…
Go’s io.Reader interface is fundamental to working with streams of data. When you have a byte slice and need to pass it to a function expecting an io.Reader, the standard library provides straightforward solutions. Using bytes.NewReader The most direct approach is bytes.NewReader(), which wraps a byte slice in an io.Reader: package main import ( “bytes”…
The most straightforward approach is using ioutil.ReadFile() or the modern os.ReadFile() function, both of which return the entire file content as a byte slice that you can convert to a string. package main import ( “fmt” “os” ) func main() { content, err := os.ReadFile(“example.txt”) if err != nil { fmt.Println(“Error reading file:”, err) return…
There are several tools available for extracting images from PDFs on Linux, each with different strengths depending on your use case and the PDF structure. pdfimages (Poppler Utils) The most straightforward approach is using pdfimages from the poppler-utils package: pdfimages document.pdf image This extracts all images and saves them as image-000.ppm, image-001.ppm, etc. By default,…
XSANE is a graphical scanner interface for Linux that provides straightforward scanning capabilities. When you scan documents or images, the JPEG output files can be surprisingly large depending on your settings. Here are practical methods to reduce the file size. Adjust JPEG Quality in XSANE The most direct approach is to lower the JPEG quality…
In Go, a string is a read-only slice of bytes, while a rune is an alias for int32 representing a Unicode code point. Understanding this distinction is essential when you need to work with individual characters, especially in multilingual text. Basic Conversion The simplest approach is direct type conversion: s := “Hello, 世界” runes :=…
Error handling is fundamental to Go development. Often you’ll need to convert an error to a string for logging, displaying to users, or including in API responses. Go provides several straightforward approaches. Using the Error() Method Every error in Go implements the error interface, which has a single method: Error() string. The simplest conversion is…
The kernel log buffer (dmesg) outputs timestamps in seconds since boot by default, making it difficult to correlate events with wall-clock time or other system logs. Here’s how to convert them to human-readable format. Using journalctl Instead of dmesg The modern approach is to use journalctl, which handles timestamp formatting automatically: journalctl -b This shows…
When you need to access files from a Xen guest’s disk image without booting the VM, you can attach and mount its partitions directly on the host using kpartx. This is useful for recovery, forensics, backup verification, or migrating data between systems. Using kpartx to expose partitions The kpartx utility creates device mappings for partitions…
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:…
Extracting images embedded in PDF files is straightforward on Linux with several reliable tools. Here are the most practical approaches, from GUI tools to command-line solutions. GUI Tools LibreOffice Draw remains the simplest option if you prefer a graphical interface. Open the PDF file in LibreOffice Draw, right-click on any image, and select “Save Image…
Merging SAM files is a common task in bioinformatics workflows, and while samtools merge works directly with BAM files, you need a different approach for SAM files. The most efficient method leverages the SAM format structure: headers start with @, and alignment records don’t. Why not convert to BAM first? Converting SAM to BAM, merging…
When submitting images to publishers or print shops, you’ll often need CMYK color space instead of RGB. The conversion is straightforward on Linux using ImageMagick’s convert command. Basic conversion The simplest approach uses the -colorspace option: convert from.tif -colorspace CMYK to.tif This works, but CMYK TIFF files can be quite large. Add compression to keep…
PowerPoint’s export function defaults to 96 DPI, which is suitable for screen display but inadequate for printing posters, documents, or any material requiring high resolution. While PowerPoint includes DPI settings, they’re often unreliable or have limited effect on TIFF output. Here are the practical methods to generate proper high-DPI TIFF files from PowerPoint slides. PowerPoint’s…
Many PDF-to-text conversions strip away formatting and spatial relationships, making tables unreadable and multi-column layouts collapse into linear text. If you need to preserve the relative positions of text elements—especially tables, columns, and indentation—you have several solid options. pdftotext with layout preservation The simplest approach is pdftotext, which comes with most distributions as part of…
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);…