diff --git a/services/vault/scripts/vault_k8s_auth_configure.sh b/services/vault/scripts/vault_k8s_auth_configure.sh
index 9e2f674..4457fc6 100644
--- a/services/vault/scripts/vault_k8s_auth_configure.sh
+++ b/services/vault/scripts/vault_k8s_auth_configure.sh
@@ -4,17 +4,17 @@ set -eu
 log() { echo "[vault-k8s-auth] $*"; }
 
 status_json="$(vault status -format=json || true)"
-if [[ -z "${status_json}" ]]; then
+if [ -z "${status_json}" ]; then
   log "vault status failed; check VAULT_ADDR and VAULT_TOKEN"
   exit 1
 fi
 
-if ! grep -q '"initialized":true' <<<"${status_json}"; then
+if ! printf '%s' "${status_json}" | grep -q '"initialized":true'; then
   log "vault not initialized; skipping"
   exit 0
 fi
 
-if grep -q '"sealed":true' <<<"${status_json}"; then
+if printf '%s' "${status_json}" | grep -q '"sealed":true'; then
   log "vault sealed; skipping"
   exit 0
 fi