打开接口时，是否运行/etc/network/if-up.d中的每个脚本？

启用网络接口后，/ etc / network / if-up.d中的所有脚本都运行吗？

如果是这样，则interfaces文件中的post-up命令是什么？

是的，通常会运行任何标记为可执行并放置在该文件夹中的脚本。由于使用了运行部件，因此文件确实限于一组特定的名称。

在post-up做同样的事情使用up。将脚本放在if-up.d中与使用a post-up指向其他地方的脚本或命令相同。通常，当您只需要为单个界面运行单个命令时，便会使用up | post-up。当您遇到更复杂的事情时，可以创建一个脚本。

人机界面

...
up command

post-up command
      Run  command  after  bringing the interface up.  If this command
      fails then ifup aborts, refraining from marking the interface as
      configured  (even  though it has really been configured), prints
      an error message, and exits with status 0.   This  behavior  may
      change in the future.
...
There  exists  for  each  of  the  above  mentioned options a directory
/etc/network/if-<option>.d/ the scripts in which are run (with no argu-
ments) using run-parts(8) after the option itself has been processed.

人跑零件

run-parts  runs  all  the  executable  files  named  within constraints
described below,

If  the  --lsbsysinit  option  is not given then the names must consist
entirely of upper and lower  case  letters,  digits,  underscores,  and
hyphens.
...
Files are run in the lexical sort  order  of  their  names  unless  the
--reverse  option  is given, in which case they are run in the opposite
order.