1 files changed, 3 insertions, 1 deletions
diff --git a/docs/fs.md b/docs/fs.md
index 339c14ba..4b772c18 100644
--- a/docs/fs.md
+++ b/docs/fs.md
@@ -559,7 +559,9 @@ directory. A name alone is no edit: the pane's `dirty` stays what its text made
 Restore or Del, which ask only about text edited), and `Save` writes it
 under the new name all the same. An open's writes are one name: held
 until its newline, or its close when it has none, then applied once, however
-the writes cut it; nothing else is trimmed. A blank inside a name is taken
+the writes cut it; nothing else is trimmed. Two lines are refused, EINVAL,
+in one write or as a second line on the same open (bash's `printf
+'a\nb\n' > name` writes a line at a time: the first names it). A blank inside a name is taken
 (`two words.zig`); refused, EINVAL, in acme's words (xfid.c:650) and why,
 are a blank at either end (not quietly cut off), `bad character in file
 name: a blank at its end`, a second line, `...: a newline (a name is one