# Magical File Descriptors and Redirections In the realm of magic, file descriptors are like **magical conduits** that connect spellcasters (programs or users) to sources and destinations of magical energy. These sources could be **scrolls** (files), **pools** (input/output devices), or even other **spellcasters**. **Redirections** are like shifting the flow of energy, guiding it along different paths. This allows spellcasters to control how their spells interact with the magical world around them. ## The Essence of Magical Conduits (File Descriptors) Picture a wizard casting a spell to draw energy from a specific enchanted pool (an input source). A file descriptor acts as the conduit that connects the caster’s spell to that pool, allowing the magic to flow. Similarly, when a spell needs to release energy—whether it’s etching runes onto a scroll (writing to a file) or casting a beam of light (output to a display)—the file descriptor directs the magic where it needs to go. ### The Three Core Conduits In this magical world, there are three main conduits that every spellcaster can use: 1. **STDIN (Standard Input)** - _File Descriptor 0_ - Channels magical energy from the primary input source, like a wizard’s enchanted tablet (keyboard). 2. **STDOUT (Standard Output)** - _File Descriptor 1_ - Directs the results of a spell’s execution to the caster’s primary output, often a mystical crystal ball (the terminal screen). 3. **STDERR (Standard Error)** - _File Descriptor 2_ - This conduit is for channeling mishaps, errors, or warnings during spell execution. It’s like sparks or smoke signaling the caster that something went wrong (error messages on the terminal). ## Mastering the Art of Redirections Redirections are powerful spells that modify these conduits, altering the flow of magical energy. ### Types of Redirection Spells #### Output Redirection (">") - Imagine a wizard casting a powerful divination spell and wanting to record the results in a scroll, not just display them in their crystal ball. - With the ">" rune, they can redirect the energy from the STDOUT conduit to the scroll, saving the magical data for later use. #### Appending Output (">>") - Sometimes, a wizard wants to add new energy to an existing scroll without erasing the previous inscriptions. - Using the ">>" runes, they can append new magical energy to the existing flow, preserving the past spells. #### Input Redirection ("<") - This spell is used when a wizard needs to imbue a potion with magical energy from a scroll. - By casting the "<" rune, the wizard channels the magical energy from the scroll directly into their brewing cauldron. #### Error Redirection ("2>") - If a wizard wants to hide the visual manifestations of errors, they might instead want to store them in a containment crystal for later examination. - The "2>" runes serve as the redirection, funneling error energy into the crystal. #### Magical Pipes ("|") - Pipes are enchanted conduits that connect one spell’s output directly to another spell’s input. - For example, a wizard might use a divination spell to gather magical information and then pipe that data into a filtering spell to only focus on creatures with healing properties. ## Conclusion By thinking of file descriptors as magical conduits and redirections as spells that alter the flow of energy, we can better understand how they work together to control the movement of information. Each file descriptor represents a unique magical connection, while redirections give spellcasters the power to manipulate these flows. With these tools, users (or wizards) can craft intricate spells and achieve their desired outcomes in the magical world—or, in our case, the world of computing. ### Some Spells Related `find / -type f -name "*.bak" 2>/dev/null | wc -l`