diff --git a/scripts/ci.sh b/scripts/ci.sh
index 3aab7c6..cb44184 100755
--- a/scripts/ci.sh
+++ b/scripts/ci.sh
@@ -46,8 +46,8 @@ EOF
 
 # $1: SSH private key
 write_ssh(){
-	echo > $SSH_ID_FILE
-	echo "$1" >> $SSH_ID_FILE
+	truncate --size 0 $SSH_ID_FILE
+	echo "$1" > $SSH_ID_FILE
 	chmod 600 $SSH_ID_FILE
 }