■ 🕑 2. explanation console stdin, stdout, redirection
   #!/bin/bash
   # ┏━┓╻  ┏━┓╻ ╻┏┓╻╻ ╻┏┳┓┏━┓╻ ╻   USAGE: playnumpv <days>
   # ┣━┛┃  ┣━┫┗┳┛┃┗┫┃ ┃┃┃┃┣━┛┃┏┛   (where days = number of days to 
   # ╹  ┗━╸╹ ╹ ╹ ╹ ╹┗━┛╹ ╹╹  ┗┛    search back for newer media files)
   
   # Check if argument is provided
   if [ -z "$1" ] || [[ ! "$1" =~ ^[0-9]+$ ]]; then
     echo "Usage: $0 <days>"
     exit 1
   fi
   
   # Create a temporary playlist file in a safe location
   playlist=$(mktemp) || { echo "Failed to create temporary file"; exit 1; }
   
   # Set trap to clean up temporary file on exit
   trap 'rm -f "$playlist"' EXIT
   
   # Get absolute path of the playlist to exclude it from search
   abs_playlist=$(realpath "$playlist")
   
   # Find all media files modified in the last $1 days and add them to the playlist
   # Using absolute paths to avoid issues with relative paths
   find "$PWD" -type f -regextype posix-extended -regex '.*\.(mp3|flac|opus|ogg|m4a|wav|nsf|mod|xm)' \
     -mtime -"${1}" ! -path "$abs_playlist" -print0 | \
     sort -z | \
     tr '\0' '\n' > "$playlist"
   
   # Check if any files were found
   if [ ! -s "$playlist" ]; then
     echo "No files found newer than ${1} days."
     exit 0
   fi
   
   # Count the number of files in the playlist
   file_count=$(wc -l < "$playlist")
   echo "Found $file_count files to play."
   
   # Play the playlist with mpv, using unbuffer to maintain terminal connection
   # and process substitution to capture output without breaking stdin
   unbuffer -p mpv --shuffle --term-osd=auto --osd-level=2 --no-audio-display \
     --playlist="$playlist" 2>&1 > >(grep -E "Playing") < /dev/tty
   
   # Multi-line comment explaining the redirection technique:
   : <<'EOF'
   EXPLANATION OF THE REDIRECTION TECHNIQUE:
   
   The command uses several advanced shell features to maintain keyboard control while filtering output:
   
   1. `unbuffer -p`:
      - Creates a pseudo-terminal for mpv
      - Ensures mpv maintains interactive behavior including keyboard input handling
   
   2. `2>&1`:
      - Redirects stderr to stdout
      - Combines both output streams
   
   3. `> >(grep -E "Playing")`:
      - Uses process substitution (the `>(...)` syntax)
      - Creates a temporary file descriptor connected to grep
      - Sends mpv's output to grep without breaking terminal connection
      - Unlike a regular pipe, this doesn't disrupt keyboard input
   
   4. `< /dev/tty`:
      - Explicitly redirects stdin to the terminal device
      - Ensures mpv gets keyboard input directly from the terminal
      - This is critical for maintaining keyboard control
   
   WHY THIS WORKS WHEN REGULAR PIPES FAIL:
   
   Regular pipes (mpv | grep) break keyboard input because:
   - The shell puts commands in separate process groups
   - mpv detects its output is going to a pipe and may change behavior
   - Terminal control gets disrupted
   
   Our solution works because:
   - unbuffer maintains the terminal connection
   - Process substitution doesn't break the terminal connection like a pipe
   - Explicit terminal input redirection ensures keyboard control
   - The combination preserves mpv's interactive capabilities
   
   DATA FLOW:
   Keyboard Input → /dev/tty → mpv (via unbuffer) → Process Substitution → grep → Terminal
   EOF