diff --git a/linux/docker install.md b/linux/docker install.md
index 98765c1..3cc8cee 100644
--- a/linux/docker install.md	
+++ b/linux/docker install.md	
@@ -1,5 +1,7 @@
 # install
 sudo apt-get update
+sudo apt update
+sudo apt install gnupg
 sudo apt-get install apt-transport-https ca-certificates curl software-properties-common
 curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
 sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"