Programming languages and software development
In C, the most straightforward way to store a homogeneous collection of objects is an array. An array is a contiguous block of memory holding elements of identical type, with the first element at the lowest address and subsequent elements following immediately after. Arrays provide O(1) random access to any element and are efficient for…
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 =…
The epoch timestamp (seconds since January 1, 1970 UTC) is fundamental for Unix timekeeping. Every process needs reliable time access — whether for logging, scheduling, or benchmarking. Basic Second-Level Precision For simple timestamp needs, use time(): #include <time.h> time_t now = time(NULL); printf(“Current epoch: %ld\n”, (long)now); This returns seconds since epoch as a time_t. It’s…
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…
The Unix epoch (seconds since January 1, 1970 UTC) is the standard for representing time across systems. Perl gives you straightforward access to this value. Basic epoch timestamp The simplest way to get the current epoch time: my $epoch = time(); print $epoch; # prints something like 1735689600 The time() function returns an integer representing…
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() {…
The standard sort command is single-threaded by default, which limits performance on modern multi-core systems. Several approaches exist to speed up sorting operations using parallelism. GNU Sort with Parallel Sorting Modern versions of GNU sort (8.23+) include built-in parallel sorting support. Enable it with the –parallel flag: sort –parallel=4 large_file.txt > sorted_output.txt The –parallel option…
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…
When working with Hadoop Distributed File System (HDFS), files containing spaces in their names require special handling during the hdfs dfs -put command. Without proper escaping or quoting, the shell interprets spaces as delimiters, splitting the filename into multiple arguments. Direct Upload with Quoting The simplest approach is to wrap the filename in quotes: hdfs…
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…