diff --git a/Command-line.md b/Command-line.md
index e517fa7..bac49df 100644
--- a/Command-line.md
+++ b/Command-line.md
@@ -77,9 +77,15 @@ Examples:
 -l xml
 </pre>
 
-## Sending output to a file
+## Sending output to a file or stream
 <pre>
--o, --out &lt;filename>
+-o, --out &lt;filename> | &lt;%streamname>
 </pre>
 
-Use this option to send all output to a file. Without the option output is sent to stdout (note that uses of stdout and stderr *from within test cases* are redirected and included in the report - so even stderr will effectively end up on stdout).
+Use this option to send all output to a file or a stream. By default output is sent to stdout (note that uses of stdout and stderr *from within test cases* are redirected and included in the report - so even stderr will effectively end up on stdout). If the name begins with % it is interpretted as a stream. Otherwise it is treated as a filename.
+
+Recognised stream names are:
+
+* %stdout
+* %stderr
+* %debug (The IDE's debug output window - currently only Windows' OutputDebugString is supported).
\ No newline at end of file