diff --git a/src/script/arch-update.sh b/src/script/arch-update.sh
index 62cfdb5..bce0dfd 100755
--- a/src/script/arch-update.sh
+++ b/src/script/arch-update.sh
@@ -77,8 +77,8 @@ if grep -Eq '^[[:space:]]*PrivilegeElevationCommand[[:space:]]*=[[:space:]]*(sud
 	su_cmd=$(grep -E '^[[:space:]]*PrivilegeElevationCommand[[:space:]]*=[[:space:]]*(sudo|doas|run0)[[:space:]]*$' "${config_file}" 2> /dev/null | awk -F '=' '{print $2}' | tr -d '[:space:]')
 fi
 
-if grep -Eq '^[[:space:]]*DiffProg[[:space:]]*=[[:space:]].*[[:space:]]*$' "${config_file}" 2> /dev/null; then
-	diff_prog=$(grep -E '^[[:space:]]*DiffProg[[:space:]]*=[[:space:]].*[[:space:]]*$' "${config_file}" 2> /dev/null | awk -F '=' '{print $2}' | tr -d '[:space:]')
+if grep -Eq '^[[:space:]]*DiffProg[[:space:]]*=[[:space:]]*[^[:space:]].*[[:space:]]*$' "${config_file}" 2> /dev/null; then
+	diff_prog=$(grep -E '^[[:space:]]*DiffProg[[:space:]]*=[[:space:]]*[^[:space:]].*[[:space:]]*$' "${config_file}" 2> /dev/null | awk -F '=' '{print $2}' | tr -d '[:space:]')
 fi
 
 # Definition of the colors for the colorized output