diff --git a/functions.sh b/functions.sh
index b7b6b18..f8d44a8 100755
--- a/functions.sh
+++ b/functions.sh
@@ -956,7 +956,7 @@ loadagent() {
     af=$(sshstartagent --create-only $1 )
     loginfo "Load agent from $af"
     unset SSH_AUTH_SOCK SSH_AGENT_PID PKCS11_MODULE
-    [ -n "${af+x}" ] && eval $(<$af)
+    [ -n "${af:+x}" ] && eval $(<$af)
     if which tmux 1>/dev/null 2>&1 
     then
         [ -n "${SSH_AUTH_SOCK:-}" ] && tmux set-environment SSH_AUTH_SOCK $SSH_AUTH_SOCK