Programming languages (Python, JavaScript, C++, Go, Rust, Java) and their frameworks and libraries.
When you need to load configuration files, data files, or assets relative to your script’s location, the current working directory won’t work — it depends entirely on where you called the script from, not where the script actually lives. Use pathlib.Path: from pathlib import Path # The directory where the script lives script_dir = Path(__file__).resolve().parent…
The stat() system call is the traditional approach for checking file existence: #include <sys/stat.h> int file_exists(const char *path) { struct stat buffer; return (stat(path, &buffer) == 0); } This returns 1 if the file exists, 0 otherwise. The stat() call fills the buffer with file metadata, but when checking existence alone, you’re mainly interested in…
URL encoding (percent-encoding) converts special characters into a format safe for transmission over HTTP. In Python, the urllib.parse module provides straightforward functions for decoding these strings. Basic Decoding with unquote The unquote() function is the standard approach: from urllib.parse import unquote encoded_url = “https://example.com/search?q=hello%20world” decoded_url = unquote(encoded_url) print(decoded_url) # Output: https://example.com/search?q=hello world This handles the…
In C++11, lambda parameters required concrete types. Creating a truly generic lambda meant wrapping the logic in a template struct — awkward and verbose. C++14 introduced generic lambdas using auto for parameter deduction, eliminating this friction entirely. Basic Generic Lambda Syntax The simplest approach uses auto in lambda parameters: auto add = [](auto a, auto…
On Linux, block special files represent hardware devices like hard drives, SSDs, and other block devices. They’re typically found in /dev and can be identified using Python’s stat module combined with os.stat(). The Standard Approach import os import stat path = “/dev/sda” try: mode = os.stat(path).st_mode if stat.S_ISBLK(mode): print(f”{path} is a block device”) except FileNotFoundError:…
When you need to open a file for both reading and writing, creating it if it doesn’t exist, C++ offers several approaches. The choice depends on your project’s requirements and how much control you need over the process. Using std::fstream The most straightforward modern approach uses std::fstream, part of the standard library: #include <fstream> std::fstream…
C++20 introduced std::string::starts_with(), which is the most straightforward way to check if a string begins with a specific substring: #include <iostream> #include <string> int main() { std::string text = “big string here…”; std::cout << std::boolalpha; std::cout << text.starts_with(“big”) << std::endl; // true std::cout << text.starts_with(“small”) << std::endl; // false std::cout << text.starts_with(“big string”) << std::endl;…
Splitting strings by a delimiter is a common task in systems programming. C++ doesn’t provide a built-in split function like Python, but you can implement one efficiently using the standard library. Using std::istringstream and getline() The standard approach uses std::istringstream with std::getline(). The getline() function accepts a delimiter parameter, allowing you to extract tokens until…
The Linux command readlink -m resolves a path to its absolute, canonical form, following all symlinks and resolving .. and . components. Python provides several ways to do this, depending on your needs and Python version. Using pathlib.Path.resolve() The modern standard approach uses pathlib: from pathlib import Path canonical_path = Path(“./../folder/./file.txt”).resolve() print(canonical_path) Path.resolve() returns an…
Using operator[] on a const map will fail to compile. This code: #include <iostream> #include <string> #include <map> std::int64_t count(const std::map<std::string, std::int64_t>& map) { return map[“one”] + map[“two”]; } int main() { std::map<std::string, std::int64_t> map = { {“one”, 1}, {“two”, 2} }; std::cout << count(map) << std::endl; return 0; } produces a compiler error: error:…
Vim’s default indentation can mangle C++11 lambdas, treating them like nested blocks instead of closures. The lambda body gets indented too far relative to the enclosing statement. The Problem Given this code: #include <iostream> #include <string> #include <vector> #include <algorithm> int main() { std::vector<std::string> strs({“one”, “two”}); std::vector<std::string> newstrs; std::transform(strs.begin(), strs.end(), std::back_inserter(newstrs), [](const std::string& s) ->…
In C++, you have several ways to output to standard output and standard error streams. The choice depends on your project’s requirements and whether you’re working with older codebases or modern C++. Using std::cout and std::cerr The standard approach uses the C++ iostream library: #include <iostream> int main() { std::cout << “This goes to standard…
Java provides straightforward ways to direct output to standard output and standard error streams. Understanding the difference between them is essential for proper logging and error handling. System.out vs System.err System.out and System.err are both PrintStream objects, but they serve different purposes: System.out: Standard output stream for normal program output System.err: Standard error stream for…
In PHP, STDOUT and STDERR are standard output streams that handle different types of output. STDOUT carries normal program output, while STDERR carries error messages and diagnostic information. Properly directing output to the correct stream is essential for building reliable scripts and applications. Using fwrite() with Stream Handles The most straightforward approach uses fwrite() with…
By default, print() writes to STDOUT. Both STDOUT and STDERR go to your terminal unless you redirect them. Here’s how to send output to each stream explicitly. Printing to STDOUT The standard print() function writes to STDOUT and automatically adds a newline: print(“your message”) Printing to STDERR To print to STDERR, pass the file parameter:…
Go provides straightforward ways to write to standard output and standard error streams. Understanding when and how to use each is essential for building robust applications, especially in containerized and cloud environments where log separation matters. Using the fmt Package The fmt package is the most common approach for printing to STDOUT: package main import…
To get the parent process ID (PPID) of the running process, use the os.getppid() function: import os ppid = os.getppid() print(f”Parent Process ID: {ppid}”) This returns the process ID of the parent process as an integer. On Unix-like systems, this is straightforward. On Windows, the behavior is consistent as well. Accessing Full Process Information For…
Getting a process’s parent process ID (PPID) is useful for monitoring, debugging, and process management tasks. Go provides straightforward ways to access this information across different platforms. Using the os Package The simplest approach is the os package, which works on Unix-like systems: package main import ( “fmt” “os” ) func main() { ppid :=…
To retrieve the parent process ID (PPID) of the current running process, use the getppid() system call. This is the standard and portable approach on Unix-like systems including Linux. #include <stdio.h> #include <unistd.h> int main() { pid_t ppid = getppid(); printf(“Parent process ID: %d\n”, ppid); return 0; } Compile and run: gcc -o get_ppid get_ppid.c…
The standard way to get your running process’s PID in Go is through the os package: package main import ( “fmt” “os” ) func main() { pid := os.Getpid() fmt.Println(“Current PID:”, pid) } os.Getpid() returns an int representing the current process’s ID. This works across all platforms—Linux, macOS, Windows, and others. Getting the Parent Process…