fern.go: add doc

1 files changed, 37 insertions, 1 deletions

diff --git a/fern.go b/fern.go
index 5d3f3d2..21f9206 100644
--- a/fern.go
+++ b/fern.go
@@ -1,6 +1,42 @@
 // SPDX-License-Identifier: ISC
 // Copyright © 2021 siddharth <s@ricketyspace.net>
 
+// fern is a simple media feed downloader.
+//
+// It depends on yt-dlp to download the media found in the media feeds
+// to your computer.
+//
+// fern currently supports YoutTube and NPR feeds.
+//
+// Information about what media feeds to download, the location of
+// yt-dlp program on your computer, and the directory where the media
+// should be downloaded to must be specified in a config file which
+// fern expects to be at $HOME/.config/fern/fern.json
+//
+// fern's config file contains three fields:
+//
+//     {
+//        "ydl-path": "/usr/local/bin/yt-dlp",
+//        "dump-dir": "~/media/feeds", // media feed download directory
+//        "feeds": [...] // list of media feeds.
+//     }
+//
+//  Each item in the media "feeds" must be:
+//
+//     {
+//        "id": "media-feed-id", // uniquid identifier for the media feed
+//        "source": "https://feeds.npr.org/XXXX/rss.xml", // media feed url
+//        "schema": "npr", // should be "youtube" or "npr"
+//        "last": 5 // The last N items that should be downloaded
+//     }
+//
+// You may download an example config file for fern from
+// https://ricketyspace.net/fern/fern.json
+//
+// fern does not take any arguments, to run it just do:
+//
+//    $ fern
+//
 package main
 
 import (
@@ -25,7 +61,7 @@ func init() {
 		os.Exit(1)
 	}
 
-	// Initialize process  state.
+	// Initialize process state.
 	pState = state.NewProcessState()
 
 	// Open database.