diff --git a/build/tfs/linux/build.sh b/build/tfs/linux/build.sh
index e815bffd18a..f6327f28756 100755
--- a/build/tfs/linux/build.sh
+++ b/build/tfs/linux/build.sh
@@ -14,7 +14,7 @@ export AZURE_DOCUMENTDB_MASTERKEY="$6"
 export LINUX_REPO_PASSWORD="$7"
 VSO_PAT="$8"
 export SNAPCRAFT_MACAROON="$9"
-export SNAPCRAFT_UNBOUND_DISCHARGE="$10"
+export SNAPCRAFT_UNBOUND_DISCHARGE="${10}"
 
 echo "machine monacotools.visualstudio.com password $VSO_PAT" > ~/.netrc