Fix shellcheck github action

.github/workflows/shellcheck.yml

@@ -4,6 +4,7 @@ on: [push, pull_request]
 
 jobs:
   shellcheck:
-    - runs-on: ubuntu-latest
+    runs-on: ubuntu-latest
+    steps:
       - name: shellcheck
         uses: ludeeus/action-shellcheck@0.1.0

tdrop

@@ -181,7 +181,7 @@ done
 shift "$((OPTIND-1))"
 program=$1
 
-if [[ -z $program_flags ]]; then
+if [[ ${#program_flags[@]} -eq 0 ]]; then
 	program_flags=("${@:2}")
 fi