diff --git a/usr/bin/dracut-ukify b/usr/bin/dracut-ukify
index c43c736..290b256 100755
--- a/usr/bin/dracut-ukify
+++ b/usr/bin/dracut-ukify
@@ -76,11 +76,11 @@ EOF
     if [ -f "${i}" ]
     then
       echo "${i} exist"
-      keys_count=$(expr $keys_count + 1)
+      keys_count=$(($keys_count + 1))
     fi
   done
 
-  if [[ $keys_count -lt 6 ]]
+  if [ $keys_count -lt 6 ]
   then
     for i in "${keys[@]}"
     do
@@ -88,13 +88,13 @@ EOF
       then
         echo "${i} remove"
         rm "${i}"
-        keys_count=$(expr $keys_count - 1)
+        keys_count=$(($keys_count - 1))
       fi
     done
   fi
   echo "Keys = $keys_count"
 
-  if [ -f "${ukify_conf}" ] && [[ $keys_count == 0 ]]
+  if [ -f "${ukify_conf}" ] && [ $keys_count == 0 ]
   then
     echo "Generate keys"
     /usr/lib/systemd/ukify genkey --config "${ukify_conf}"
@@ -181,7 +181,7 @@ if (( update_all )); then
   for kernel_path in /usr/lib/modules/*; do
     [ -f "$kernel_path/pkgbase" ] || continue
 
-    kernel_version=$(basename $kernel_path)
+    kernel_version=$(basename "$kernel_path")
     kernel_dir="/usr/lib/modules/$kernel_version"
     pkgbase="$kernel_dir/pkgbase"
     kernel_name=$(sed -e 's/^[[:space:]]//g' -e 's/[[:space:]]$//g' "$pkgbase")
@@ -207,13 +207,13 @@ function gen_image() {
     cmdline=$(sed -e 's/^[[:space:]]//g' -e 's/[[:space:]]$//g' "/etc/kernel/cmdline")
 
   elif [ -f "/boot/refind_linux.conf" ]; then
-    cmdline=$(cat "/boot/refind_linux.conf" | head -n 1 | sed -e 's|"Boot with standard options"||g' | awk '{$1=$1;print}' | sed -e 's/"//g')
+      cmdline=$(head -n 1 < "/boot/refind_linux.conf" | sed -e 's|"Boot with standard options"||g' | awk '{$1=$1;print}' | sed -e 's/"//g')
 
   elif [ -f "/efi/refind_linux.conf" ]; then
-    cmdline=$(cat "/efi/refind_linux.conf" | head -n 1 | sed -e 's|"Boot with standard options"||g' | awk '{$1=$1;print}' | sed -e 's/"//g')
+      cmdline=$(head -n 1 < "/efi/refind_linux.conf" | sed -e 's|"Boot with standard options"||g' | awk '{$1=$1;print}' | sed -e 's/"//g')
 
   elif [ -f "/boot/efi/refind_linux.conf" ]; then
-    cmdline=$(cat "/boot/efi/refind_linux.conf" | head -n 1 | sed -e 's|"Boot with standard options"||g' | awk '{$1=$1;print}' | sed -e 's/"//g')
+      cmdline=$(head -n 1 < "/boot/efi/refind_linux.conf" | sed -e 's|"Boot with standard options"||g' | awk '{$1=$1;print}' | sed -e 's/"//g')
 
   else
     cmdline=$(sed -e 's/^[[:space:]]//g' -e 's/[[:space:]]$//g' -e 's/initrd.*$//g' "/proc/cmdline")