diff --git a/Crafting-Guide-Data-Format-V2.md b/Crafting-Guide-Data-Format-V2.md
index 35dcedd..edcc258 100644
--- a/Crafting-Guide-Data-Format-V2.md
+++ b/Crafting-Guide-Data-Format-V2.md
@@ -44,7 +44,7 @@ Each line of the file should usually contain a single command. Each command has
 You can check your file for errors by running the `./scripts/verify <file>` command on your file.  This examine the file and print out any errors.  If no errors are found, there is no output.  While working on a data file, it is often handy to use the UNIX `watch` command to provide continuous feedback: `watch ./script/verify <file>`.
 
 You can pretty-print a data file using the `./scripts/reformat <file> (<output>|-)?` command.  This will 
-correct indentation, alphabetize items, and generally clean things up.
+correct indentation, alphabetize items, and generally clean things up.  Omitting the second argument will reformat the given file in place.  Providing a `-` as the second argument will print the reformatted file to `stdout` without actually modifying the original.
 
 Please be sure to use these two commands prior to submitting a pull request for a new data file!