diff --git a/README.md b/README.md
index 5986c05..043188e 100644
--- a/README.md
+++ b/README.md
@@ -256,7 +256,7 @@ sudo dnf install \
 Create a temporary directory which will be cleared on [reboot](https://en.wikipedia.org/wiki/Tmpfs) and set it as the GnuPG directory:
 
 ```console
-GNUPGHOME=$(mktemp -d -t gnupg-$(date +%Y-%m-%d)-XXXXXXXXXX)
+export GNUPGHOME=$(mktemp -d -t gnupg-$(date +%Y-%m-%d)-XXXXXXXXXX)
 ```
 
 ## Configuration