diff --git a/scripts/create-uefi.sh b/scripts/create-uefi.sh
index 64a433f..328b4fb 100755
--- a/scripts/create-uefi.sh
+++ b/scripts/create-uefi.sh
@@ -1,6 +1,12 @@
 #! /usr/bin/env nix-shell
 #! nix-shell -i bash -p parted
 
+# Fail if $SUDO_USER is empty.
+if [ -z "$SUDO_USER" ]; then
+    printf "This script must be run with sudo.\n"
+    exit 1
+fi
+
 DISK=/dev/mmcblk0
 set -e
 
diff --git a/scripts/format-disk.sh b/scripts/format-disk.sh
index bc2d618..1800c6f 100755
--- a/scripts/format-disk.sh
+++ b/scripts/format-disk.sh
@@ -1,9 +1,16 @@
 #! /usr/bin/env nix-shell
 #! nix-shell -i bash -p parted
 
-DISK=/dev/sdb
 set -e
 
+# Fail if $SUDO_USER is empty.
+if [ -z "$SUDO_USER" ]; then
+    printf "This script must be run with sudo.\n"
+    exit 1
+fi
+
+DISK=/dev/sdb
+
 BOOT_PARTITION="$DISK"1
 ROOT_PARTITION="$DISK"2
 ROOT_DIR=/mnt/nixos
diff --git a/scripts/rename-partitions.sh b/scripts/rename-partitions.sh
index c7cd10d..83c1885 100755
--- a/scripts/rename-partitions.sh
+++ b/scripts/rename-partitions.sh
@@ -3,6 +3,12 @@
 
 set -e
 
+# Fail if $SUDO_USER is empty.
+if [ -z "$SUDO_USER" ]; then
+    printf "This script must be run with sudo.\n"
+    exit 1
+fi
+
 rename_boot_partition() {
     echo "Rename boot partition."
     fatlabel /dev/disk/by-label/BOOTTOFRMT BOOT