默认的 Windows shell
尽管微软指定 %COMSPEC%
必须包含根环境中到 'cmd.exe'
的路径,但子进程并不总是受到相同的要求。
因此,在可以衍生 shell 的 child_process
函数中,如果 process.env.ComSpec
不可用,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.