diff --git a/bin/b2-ul_me b/bin/b2-ul_me
index bcd00d6..17e8b74 100644
--- a/bin/b2-ul_me
+++ b/bin/b2-ul_me
@@ -2,10 +2,10 @@
 
 echo "** backblaze b2 custom uploader **"
 
-FILE_TO_UPLOAD=${1}
-MIME_TYPE=${2}
-B2_KEY_ID=${3}
-B2_KEY=${4}
+FILE_TO_UPLOAD=$1
+MIME_TYPE=$2
+B2_KEY_ID=$3
+B2_KEY=$4
 SHA1_OF_FILE=$(openssl dgst -sha1 $FILE_TO_UPLOAD | awk '{print $2;}')
 
 b2_authorize_account=$(curl -s 'https://api.backblazeb2.com/b2api/v2/b2_authorize_account' -u "$B2_KEY_ID:$B2_KEY")
@@ -14,6 +14,11 @@ apiUrl=$(echo $b2_authorize_account | jq -r '.apiUrl')
 B2_TOKEN=$(echo $b2_authorize_account | jq -r '.authorizationToken')
 B2_BUCKET_ID=$(echo $b2_authorize_account | jq -r '.bucketId')
 
+if [ -z $b2_authorize_account ]; then echo b2_authorize_account is empty && exit 1; fi
+if [ -z $apiUrl ]; then echo apiUrl is empty && exit 1; fi
+if [ -z $B2_TOKEN ]; then echo B2_TOKEN is empty && exit 1; fi
+if [ -z $B2_BUCKET_ID ]; then echo B2_BUCKET_ID is empty && exit 1; fi
+
 UPLOAD_URL=$(curl -s -H "Authorization:$B2_TOKEN" -d '{"bucketId":"$B2_BUCKET_ID"}' $apiUrl/b2api/v2/b2_get_upload_url | jq -r '.uploadUrl')
 
 curl -s -H "Authorization:$B2_TOKEN" -H "X-Bz-File-Name:$FILE_TO_UPLOAD" -H "Content-Type:$MIME_TYPE" -H "X-Bz-Content-Sha1:$SHA1_OF_FILE" -H "X-Bz-Info-Author:${DRONE_COMMIT_AUTHOR}" --data-binary "@$FILE_TO_UPLOAD" $UPLOAD_URL