docs: describe files-from comments

diff --git a/rsync.1.md b/rsync.1.md
index 3306dab0fc5e013450aa8d029b9d2d4ff52e8f8a..9e0f344694d33a150aa42fae60c4f62fc493a9f8 100644 (file)
--- a/rsync.1.md
+++ b/rsync.1.md
@@ -2390,7 +2390,9 @@ expand it.
 
     The filenames that are read from the FILE are all relative to the source
     dir -- any leading slashes are removed and no ".." references are allowed
-    to go higher than the source dir.  For example, take this command:
+    to go higher than the source dir.  Blank lines are ignored, as are
+    whole-line comments that start with '`;`' or '`#`' (unless [`--from0`](#opt)
+    is specified).  For example, take this command:
 
     >     rsync -a --files-from=/tmp/foo /usr remote:/backup