diff --git a/stack b/stack
new file mode 100644
index 0000000..3081ff0
--- /dev/null
+++ b/stack
@@ -0,0 +1,227 @@
+#!/usr/bin/env bash
+set -uo pipefail
+
+CONFIG_FILE="${STACK_CONF:-$HOME/stack.conf}"
+
+COMPOSE_CANDIDATES=(
+  "compose.yml"
+  "compose.yaml"
+  "docker-compose.yml"
+  "docker-compose.yaml"
+)
+
+usage() {
+  cat <<'EOF'
+Usage:
+  stack start
+  stack add .
+  stack add foldername
+  stack add folder1 folder2 folder3
+EOF
+}
+
+strip_quotes() {
+  local s="$1"
+  s="${s#\"}"
+  s="${s%\"}"
+  s="${s#\'}"
+  s="${s%\'}"
+  printf '%s' "$s"
+}
+
+resolve_path() {
+  local input="$1"
+  if command -v realpath >/dev/null 2>&1; then
+    realpath -m "$input"
+  else
+    python3 - "$input" <<'PY'
+import os, sys
+print(os.path.abspath(os.path.expanduser(sys.argv[1])))
+PY
+  fi
+}
+
+ensure_config_exists() {
+  if [[ ! -f "$CONFIG_FILE" ]]; then
+    mkdir -p "$(dirname "$CONFIG_FILE")"
+    cat > "$CONFIG_FILE" <<EOF
+STACK_HOME=$HOME
+# one folder per line below
+EOF
+  fi
+}
+
+load_config() {
+  STACK_HOME=""
+  STACK_DIRS=()
+
+  while IFS= read -r line || [[ -n "$line" ]]; do
+    line="${line%$'\r'}"
+    [[ -z "$line" ]] && continue
+    [[ "$line" =~ ^[[:space:]]*# ]] && continue
+
+    if [[ "$line" == STACK_HOME=* ]]; then
+      STACK_HOME="$(strip_quotes "${line#STACK_HOME=}")"
+      continue
+    fi
+
+    STACK_DIRS+=("$(strip_quotes "$line")")
+  done < "$CONFIG_FILE"
+
+  [[ -z "$STACK_HOME" ]] && STACK_HOME="$HOME"
+}
+
+compose_cmd() {
+  if docker compose version >/dev/null 2>&1; then
+    printf 'docker compose'
+  elif command -v docker-compose >/dev/null 2>&1; then
+    printf 'docker-compose'
+  else
+    echo "error: neither 'docker compose' nor 'docker-compose' is installed." >&2
+    exit 1
+  fi
+}
+
+add_folder() {
+  ensure_config_exists
+  load_config
+
+  if [[ $# -eq 0 ]]; then
+    echo "usage: stack add .|foldername|/path/to/folder [more folders...]" >&2
+    exit 1
+  fi
+
+  local added=0
+  local arg target
+  for arg in "$@"; do
+    if [[ "$arg" == "." ]]; then
+      target="$PWD"
+    elif [[ "$arg" == /* ]]; then
+      target="$arg"
+    else
+      target="$PWD/$arg"
+    fi
+
+    target="$(resolve_path "$target")"
+
+    if [[ ! -d "$target" ]]; then
+      echo "error: folder does not exist: $target" >&2
+      continue
+    fi
+
+    if grep -Fxq -- "$target" "$CONFIG_FILE"; then
+      echo "already in stack.conf: $target"
+      continue
+    fi || true
+
+    printf '%s\n' "$target" >> "$CONFIG_FILE"
+    echo "added: $target"
+    added=1
+  done
+
+  [[ "$added" -eq 0 ]] && exit 1
+}
+
+start_stacks() {
+  ensure_config_exists
+  load_config
+
+  local cc
+  cc="$(compose_cmd)"
+
+  local any=0 dir file found
+  for dir in "${STACK_DIRS[@]}"; do
+    [[ -z "$dir" ]] && continue
+
+    if [[ ! -d "$dir" ]]; then
+      echo "skipping missing folder: $dir" >&2
+      continue
+    fi
+
+    found=0
+    for file in "${COMPOSE_CANDIDATES[@]}"; do
+      if [[ -f "$dir/$file" ]]; then
+        found=1
+        any=1
+        echo "starting: $dir/$file"
+        (cd "$dir" && $cc -f "$file" up -d)
+      fi
+    done
+
+    if [[ "$found" -eq 0 ]]; then
+      echo "no compose file found in: $dir" >&2
+    fi
+  done
+
+  if [[ "$any" -eq 0 ]]; then
+    echo "no compose files were started."
+  fi
+}
+
+update_stacks() {
+  ensure_config_exists
+  load_config
+
+  local cc
+  cc="$(compose_cmd)"
+
+  local any=0 dir file found
+  for dir in "${STACK_DIRS[@]}"; do
+    [[ -z "$dir" ]] && continue
+
+    if [[ ! -d "$dir" ]]; then
+      echo "skipping missing folder: $dir" >&2
+      continue
+    fi
+
+    found=0
+    for file in "${COMPOSE_CANDIDATES[@]}"; do
+      if [[ -f "$dir/$file" ]]; then
+        found=1
+        any=1
+        echo "updating: $dir/$file"
+
+        (
+          cd "$dir" && \
+          $cc -f "$file" pull && \
+          $cc -f "$file" up -d
+        )
+      fi
+    done
+
+    if [[ "$found" -eq 0 ]]; then
+      echo "no compose file in: $dir" >&2
+    fi
+  done
+
+  if [[ "$any" -eq 0 ]]; then
+    echo "no compose files updated."
+  fi
+}
+
+main() {
+  local cmd="${1:-}"
+  shift || true
+
+  case "$cmd" in
+    start)
+      start_stacks
+      ;;
+    update)
+      update_stacks
+      ;;
+    add)
+      add_folder "$@"
+      ;;
+    ""|-h|--help|help)
+      usage
+      ;;
+    *)
+      echo "unknown command: $cmd" >&2
+      usage
+      exit 1
+      ;;
+  esac
+}
+
+main "$@"
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