Add inotify support as an alternative to interval

[Gunni]

Use case

I often want to run a command only when something in a directory changes. Tools like inotifywait can do this, but the syntax is hard to remember, while watch already provides the screen-refresh UX I prefer. Adding an inotify-triggered mode to watch would streamline this workflow.

Proposed CLI

watch --inotify=<path> <command>

Argument Explanation

• --inotify takes an argument full or relative <path> argument which must exist, and be a
  • a filename, in which case, watch adds an inotify watch on that single file
    • add a warning to the manual that many editors replace the file instead of modifying it in place, making this method unusable
  • a directory, in which case, watch recursively adds a inotify watch on the entire directory tree (limited by fs.inotify.max_user_watches)
  • may be specified multiple times to add more paths
• --inotify-events=<event1>[,<eventN>]
  • See list of event types in here
  • Defaults to: CLOSE_WRITE

Expected Behavior

1. watch recursively subscribes to inotify events for the specified directory (similar constraints to inotifywait)
2. watch initially runs once
3. On relevant events (e.g., CLOSE_WRITE), watch clears the screen and re-runs the <command>
   • Overridable with --inotify-events=<event1>[,<eventN>]

Why This Helps

• inotifywait syntax is non‑intuitive and I always have to look it up
• I already use watch constantly; an event-driven mode feels like a natural extension
• Polling intervals aren't “smart” — events are

Bonus Suggestions

• A --tail option to always keep the bottom of the command output visible
• Optional support for mouse scrolling (similar to vim in terminal environments)

Prior Art

While writing this issue, I stumbled on similar functionality in other tools.

• https://www.entrproject.org/
• https://github.com/cortesi/modd