Programming languages (Python, JavaScript, C++, Go, Rust, Java) and their frameworks and libraries.
Every running process gets a unique identifier from the operating system called a PID (Process ID). You’ll need this when managing processes, logging, creating lock files, or coordinating between parent and child processes. The POSIX standard approach The simplest way is getpid() from unistd.h: #include <unistd.h> #include <stdio.h> int main() { pid_t pid = getpid();…
The process ID (PID) is essential for logging, creating lock files, inter-process communication, and debugging. Knowing how to reliably retrieve it matters in production systems. Basic Usage The simplest way to get your process’s own PID is through the os module: import os print(os.getpid()) This returns an integer representing the current process ID. It’s lightweight…
The basic explode() function works when you have a single delimiter character, but fails when multiple consecutive delimiters should be treated as one. For example: “a string separated by space” (three spaces) should split into [“a”, “string”, “separated”, “by”, “space”] “a,,string,,separated” (double commas) should split into [“a”, “string”, “separated”] Use preg_split() with regex patterns to…
C++ remains a foundational language for systems programming and performance-critical applications. Here’s what actually matters when choosing C++ for a project. Zero-Cost Abstraction This is C++’s defining characteristic. You get high-level language features—classes, templates, standard library containers—without paying runtime overhead. The compiler eliminates abstraction layers during compilation. This means you can write clean, maintainable code…
In C++, std::vector is the standard go-to container for managing sequences of objects. It’s a dynamically resizable array that combines efficient random access with automatic memory management. A vector stores elements contiguously in memory, supporting: O(1) random access via indexing O(1) amortized push/pop operations at the end O(n) insertions and deletions in the middle Automatic…
Retrieving the hostname of the current system is a common task in systems programming, network applications, and monitoring tools. C++ provides several approaches depending on your platform and requirements. Using gethostname() The most portable approach uses the gethostname() function from <unistd.h>: #include <unistd.h> #include <iostream> #include <cstring> int main() { char hostname[256]; if (gethostname(hostname, sizeof(hostname))…
Go’s os package provides a straightforward function to retrieve the system’s hostname: package main import ( “fmt” “os” ) func main() { hostname, err := os.Hostname() if err != nil { fmt.Println(“Error:”, err) return } fmt.Println(“Hostname:”, hostname) } The os.Hostname() function returns a string containing the hostname and an error value. Always check the error—it…
There are several ways to retrieve the hostname of the current machine in Python, each with different use cases. Using socket.gethostname() The simplest and most common approach is the socket module, which is part of Python’s standard library: import socket hostname = socket.gethostname() print(hostname) This returns the hostname as a string. On most systems, this…
Epoch timestamps (seconds since January 1, 1970 UTC) are common in logs, databases, and APIs. Python’s datetime module handles conversion cleanly. Basic Conversion The simplest approach uses datetime.fromtimestamp(): from datetime import datetime epoch = 1609459200 dt = datetime.fromtimestamp(epoch) print(dt) # 2021-01-01 00:00:00 For UTC times specifically, use utcfromtimestamp(): from datetime import datetime, timezone epoch =…
Java provides multiple ways to get the current time as an epoch value. The right approach depends on whether you need milliseconds, seconds, or nanosecond precision, and whether you’re working with UTC or time zones. Using Instant for UTC timestamps The most straightforward method is Instant.now(): Instant now = Instant.now(); long epochSeconds = now.getEpochSecond(); long…
Getting the current epoch timestamp is straightforward using the time package: package main import ( “fmt” “time” ) func main() { epoch := time.Now().Unix() fmt.Println(epoch) } The time.Now().Unix() call returns the number of seconds since January 1, 1970 UTC as an int64. Getting nanosecond precision If you need higher resolution, use UnixNano() for nanoseconds since…
The epoch timestamp (also called Unix time) represents the number of seconds since January 1, 1970, 00:00:00 UTC. PHP provides several straightforward methods to obtain this value. Using time() The simplest approach is the time() function: <?php $timestamp = time(); echo $timestamp; // Output: 1704067200 (example) ?> This returns the current Unix timestamp as an…
There are two primary ways to access environment variables in Java: System.getenv() for reading variables and System.getProperty() for reading system properties. They’re different things, so understanding which one you need matters. Reading Environment Variables with System.getenv() System.getenv() retrieves variables set in your shell or container environment: String javaHome = System.getenv(“JAVA_HOME”); System.out.println(“JAVA_HOME: ” + javaHome); To…
Python offers several ways to get the current epoch timestamp, each suited to different use cases. The choice depends on your precision requirements and whether you’re working with timezone-aware operations. Using time.time() The simplest approach is time.time(), which returns the current time as a float representing seconds since the Unix epoch (January 1, 1970, 00:00:00…
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….
Reading files line by line is a common task when handling large datasets, logs, or any text-based input where loading the entire file into memory isn’t practical. PHP provides several methods, each with different memory footprints and use cases. Using fgets() The most straightforward approach uses fgets() with a file handle: $file = fopen(‘large_file.txt’, ‘r’);…
Processing files line by line is a common task in systems programming, data processing, and log analysis. C++ provides several approaches with different trade-offs in performance, memory usage, and code clarity. Using std::getline with std::ifstream The most straightforward approach uses std::getline with an input file stream: #include <fstream> #include <string> #include <iostream> int main() {…
Java has several solid REPL implementations available. Here are the main options and how to use them. jshell (Official) The best choice for most users is jshell, included in JDK 9+. It’s the official interactive shell for Java and comes with every modern Java installation. Start it immediately: jshell Basic usage: jshell> long ts =…
Go compiles quickly and go run handles small scripts, but a REPL is more practical for interactive testing and exploration. Here are the best options available today. gore gore remains the most mature Go REPL. It’s actively maintained and handles most interactive development workflows. Install it: go install github.com/motemen/gore/cmd/gore@latest Basic usage: $ gore gore version…
Reading a file line by line is memory-efficient and the standard approach for handling large text files in Python. The key is choosing the right method for your use case. The Iterator Approach (Recommended for Large Files) For most scenarios, especially with large files, use the file object as an iterator: with open(‘file.txt’, ‘r’) as…