rsstail: add page (#2249)

pages/common/rsstail.md

@@ -0,0 +1,23 @@
+# rsstail
+
+> `tail` for RSS feeds.
+
+- Show the feed of a given url and wait for new entries appearing at the bottom:
+
+`rsstail -u {{url}}`
+
+- Show the feed in reverse chronological order (newer at the bottom):
+
+`rsstail -r -u {{url}}`
+
+- Include publication date and link:
+
+`rsstail -pl -u {{url}}`
+
+- Set update interval:
+
+`rsstail -u {{url}} -i {{interval_in_seconds}}`
+
+- Show feed and exit:
+
+`rsstail -1 -u {{url}}`