又用 vscode copilot 重写 startb

至少这次可读性还不错。

bin/startb

@@ -1,40 +1,99 @@
-#!/bin/bash
-# like `start /b` in Windows CMD.
+#!/usr/bin/env bash
+# startb: start a command in the background with journald or file logging fallback.
+# Usage:
+#   startb [--log logfile] COMMAND [ARGS...]
+# Environment:
+#   STARTB_LOGFILE=... to force a log file.
 
-# PATH 不完整问题:
-# 根据 niri 启动方式的不同，niri 读到的环境变量可能也不一样。
-# - tty 进终端再 niri-session 拉起来大概是最完整的。毕竟已经加载 .xxxrc 了嘛。
-# - 而像我这样用 sddm 进的 niri，由于直接从 systemd 启动，中间也没有任何机会更新 PATH，相比就最麻烦了。
-# 根据谷鸽 AI 的回答，我这种情况只能在 ~/.config/environment.d/ 里静态补上环境变量。
-# 之前不懂的时候用的是如下的奇技淫巧：
+set -euo pipefail
 
-# PATH=$(zsh -c -i 'echo $PATH')
-# export PATH
+# PATH may be incomplete from systemd login env; restore from interactive shell.
+PATH=$(zsh -c -i 'echo $PATH')
+export PATH
 
-# https://vescrity.github.io/post/systemd-desktop-suspend/
-#systemd-run --user --scope --slice=YukiLauncher.slice --unit="$1-$$".scope /bin/sh -c '"$@"' _ "$@"
+SCRIPT_NAME="${0##*/}"
+
+usage() {
+  cat <<EOF
+Usage: ${SCRIPT_NAME} [--log logfile] COMMAND [ARGS...]
+
+--log logfile  Write logs to this file instead of journald.
+Environment variable STARTB_LOGFILE can also provide a logfile path.
+EOF
+  exit 1
+}
 
 if [ $# -lt 1 ]; then
-  echo "Usage: daemon-run COMMAND [ARGS...]"
-  exit 1
+  usage
 fi
 
-UNIT_NAME="${1##*/}-$(date +%s%N)"
-ENV_ARGS=(
-  --setenv=PATH="$PATH"
-  --setenv=NVM_DIR="$NVM_DIR"
-  --setenv=NVM_BIN="$NVM_BIN"
-)
+LOG_FILE=${STARTB_LOGFILE:-}
 
-systemd-run --user \
-  "${ENV_ARGS[@]}" \
-  --working-directory="$PWD" \
-  --slice=StartProcess.slice \
-  --unit="$UNIT_NAME" \
-  --collect \
-  -- /bin/sh -c 'exec "$@"' _ "$@"
-
-if [ $? -eq 0 ]; then
-  echo "Logs : journalctl --user -u $UNIT_NAME -f"
-  echo "Note : '$UNIT_NAME' will auto-destruct on exit."
+if [ "$1" = "--log" ] || [ "$1" = "-l" ]; then
+  shift
+  if [ $# -lt 1 ]; then
+    echo "Error: --log requires a logfile path." >&2
+    usage
+  fi
+  LOG_FILE=$1
+  shift
 fi
+
+if [ $# -lt 1 ]; then
+  usage
+fi
+
+COMMAND=("$@")
+UNIT_BASE=$(basename "${COMMAND[0]}")
+UNIT_BASE=${UNIT_BASE:-cmd}
+UNIT_NAME="${UNIT_BASE}-$(date +%Y%m%d_%H%M%S_%N)"
+
+log_to_file() {
+  local path=$1
+  mkdir -p "$(dirname "$path")" 2>/dev/null || true
+  touch "$path" || {
+    echo "Failed to touch logfile: $path" >&2
+    return 1
+  }
+
+  nohup setsid "${COMMAND[@]}" >>"$path" 2>&1 &
+  local pid=$!
+  disown "$pid" 2>/dev/null || true
+  echo "$UNIT_NAME started in background (pid=$pid), logs: $path"
+  return 0
+}
+
+log_to_journal() {
+  # 不按雪叶那样写基本记录不到输出，懒得调了，直接屏蔽。
+  # if command -v systemd-run >/dev/null 2>&1; then
+  #   systemd-run --user --scope --unit="$UNIT_NAME" -- "${COMMAND[@]}" >/dev/null 2>&1 &
+  #   local pid=$!
+  #   echo "$UNIT_NAME started in systemd scope (pid=$pid), journald logging enabled"
+  #   return 0
+  # fi
+
+  if command -v systemd-cat >/dev/null 2>&1; then
+    nohup setsid systemd-cat -t "$UNIT_NAME" -- "${COMMAND[@]}" >/dev/null 2>&1 &
+    local pid=$!
+    disown "$pid" 2>/dev/null || true
+    echo "$UNIT_NAME started with systemd-cat (pid=$pid), journald logging enabled"
+    return 0
+  fi
+
+  return 1
+}
+
+if [ -n "$LOG_FILE" ]; then
+  log_to_file "$LOG_FILE" || exit 1
+  exit 0
+fi
+
+if log_to_journal; then
+  exit 0
+fi
+
+# Fallback log path when journald is unavailable.
+LOG_FILE="/tmp/${USER:-unknown}/startb/${UNIT_NAME}.log"
+log_to_file "$LOG_FILE"
+
+