diff --git a/README b/README
index 2cb03b4..c942f88 100644
--- a/README
+++ b/README
@@ -3,6 +3,10 @@ Repositories are created in
 using
   svn co <url> <path> --ignore-externals
 
+Externals can be included by including a .externals file in the root directory of the svn checkout, which should have one directory per line. These will be included using
+  svn update <directory> --ignore-externals
+so it will *not* fetch externals recursively. Any 'recursive' externals should be included with their full path from the *original* svn root checkout.
+
 <path> uses . as a separator for subpackages: pywikipedia.spelling is a subpackage of pywikipedia. This currently works for only one level. (this actually has not been coded yet)
 
 The packages are generated nightly using a crontab entry:
diff --git a/nightly.sh b/nightly.sh
index be11048..0071273 100755
--- a/nightly.sh
+++ b/nightly.sh
@@ -30,6 +30,12 @@ do
   
   # update the SVN checkout
   svn up --ignore-externals > $LOG_DIR/$i/svn.log
+  if [ -e ".externals" ]; then
+	  cat .externals | while read external; do
+	    echo "Updating $external" >> $LOG_DIR/$i/svn.log
+	    svn up --ignore-externals $external >> $LOG_DIR/$i/svn.log
+	  done
+  fi
   svn log --limit 1 | grep -v -e '-\{72\}' > $LOG_DIR/$i/latest.log
 
   # create packages