Add note on overwriting existing files

1 files changed, 2 insertions, 0 deletions

diff --git a/README.md b/README.md
index b20b95b..3afa64e 100644
--- a/README.md
+++ b/README.md
@@ -37,6 +37,8 @@ For instance:
 
     mammoth document.docx --output-dir=output-dir
 
+Existing files will be overwritten if present.
+
 #### Styles
 
 A custom style map can be read from a file using `--style-map`.