Windows 默认的 shell

尽管微软指定在根环境中 %COMSPEC% 必须包含 'cmd.exe' 的路径,但子进程并不总是遵循相同的要求。 因此,在可以衍生 shell 的 child_process 函数中,如果 process.env.ComSpec 不可以,则使用 'cmd.exe' 作为后备。

Although Microsoft specifies %COMSPEC% must contain the path to 'cmd.exe' in the root environment, child processes are not always subject to the same requirement. Thus, in child_process functions where a shell can be spawned, 'cmd.exe' is used as a fallback if process.env.ComSpec is unavailable.