diff --git a/runtime/doc/index.txt b/runtime/doc/index.txt
index 4af59c6..cbf363a 100644
--- a/runtime/doc/index.txt
+++ b/runtime/doc/index.txt
@@ -1166,6 +1166,7 @@
 				be remapped
 |:args|		:ar[gs]		print the argument list
 |:argadd|	:arga[dd]	add items to the argument list
+:argdedupe	:argdedupe	remove duplicates from the argument list
 |:argdelete|	:argd[elete]	delete items from the argument list
 |:argedit|	:arge[dit]	add item to the argument list and edit it
 |:argdo|	:argdo		do a command on all items in the argument list