diff --git a/ssh-helper/README.md b/ssh-helper/README.md
index 6058901..804e7aa 100644
--- a/ssh-helper/README.md
+++ b/ssh-helper/README.md
@@ -26,6 +26,12 @@ docker run -it --rm -v $(pwd):/keys/ codeship/ssh-helper prepare
 
 The resulting file will be called `codeship.env`, and the value will be appended if that file already exists.
 
+You can also override few variable to have custom keys location and names.
+
+```shell
+docker run -it --rm -v $(pwd):/keys/ --env BASE_FOLDER="/keys" --env KEY_FILE="/keys/my_codeship_deploy_key" --env ENV_FILE="/keys/my_codeship.env" codeship/ssh-helper prepare
+```
+
 ## Write the Environment Variable Back to a File
 
 During your Codeship Pro builds, you need to take the environment variable and write it back to a file, to pass to the `ssh` (or similar) commands.
diff --git a/ssh-helper/ssh_helper.sh b/ssh-helper/ssh_helper.sh
index 1417a6c..6b95167 100644
--- a/ssh-helper/ssh_helper.sh
+++ b/ssh-helper/ssh_helper.sh
@@ -1,7 +1,7 @@
 #!/bin/sh
-BASE_FOLDER="/keys"
-KEY_FILE="${BASE_FOLDER}/codeship_deploy_key"
-ENV_FILE="${BASE_FOLDER}/codeship.env"
+[ -z "${BASE_FOLDER}" ] && BASE_FOLDER="/keys"
+[ -z "${KEY_FILE}" ] && KEY_FILE="${BASE_FOLDER}/codeship_deploy_key"
+[ -z "${ENV_FILE}" ] && ENV_FILE="${BASE_FOLDER}/codeship.env"
 
 ACTION=$1 && shift
 
@@ -15,7 +15,7 @@ case "${ACTION}" in
 		;;
 	write)
 		mkdir -p "${BASE_FOLDER}/.ssh/"
-		printf "${PRIVATE_SSH_KEY}\n" >> "${BASE_FOLDER}/.ssh/id_rsa"
+		printf "${PRIVATE_SSH_KEY}\n" > "${BASE_FOLDER}/.ssh/id_rsa"
 		;;
 	*)
 		echo "Usage: $0 {generate|prepare|write}"