Update README.md

Author: bartnv

README.md

@@ -27,7 +27,7 @@ Basic usage:
 
     xml-to-postgres <config.yml> [data.xml]
 
-So the YAML configuration file is a required argument. The XML input file can be passed in as the second argument or can be sent to stdin if omitted.
+So the YAML configuration file is a required argument. The XML input file can be passed in as the second argument or will be read from stdin if omitted.
 
 Example invocation:
 
@@ -41,6 +41,10 @@ Within a database transaction:
 
     xml-to-postgres config.yml data.xml | psql <database> -c 'BEGIN' -c 'TRUNCATE <table>' -c '\copy <table> from stdin' -c 'COMMIT'
 
+Read multiple files in one go:
+
+    cat *.xml | xml-to-postgres config.yml > data.dump
+
 ## Configuration
 
 See [documentation for the configuration file](https://github.com/bartnv/xml-to-postgres/wiki/Configuration-options) in the wiki.