diff --git a/.jenkins.d/util.sh b/.jenkins.d/util.sh
index 81c8931..8077a74 100644
--- a/.jenkins.d/util.sh
+++ b/.jenkins.d/util.sh
@@ -1,9 +1,39 @@
 has() {
+    local saved_xtrace
+    [[ $- == *x* ]] && saved_xtrace=-x || saved_xtrace=+x
+    set +x
+
     local p=$1
     shift
-    local x
-    for x in "$@"; do
-        [[ "${x}" == "${p}" ]] && return 0
+    local i ret=1
+    for i in "$@"; do
+        if [[ "${i}" == "${p}" ]]; then
+            ret=0
+            break
+        fi
     done
-    return 1
+
+    set ${saved_xtrace}
+    return ${ret}
 }
+export -f has
+
+sudo_preserve_env() {
+    local saved_xtrace
+    [[ $- == *x* ]] && saved_xtrace=-x || saved_xtrace=+x
+    set +x
+
+    local vars=()
+    while [[ $# -gt 0 ]]; do
+        local arg=$1
+        shift
+        case ${arg} in
+            --) break ;;
+            *)  vars+=("${arg}=${!arg}") ;;
+        esac
+    done
+
+    set ${saved_xtrace}
+    sudo env "${vars[@]}" "$@"
+}
+export -f sudo_preserve_env