自动按下 [Y] 的终端命令是什么？

Question

例如：如果我喜欢

sudo apt-get upgrade

然后我可能会在安装更新之前收到 y/n 问题。自动接受它的参数是什么。

Answer 1

有两种方法可以做到这一点：

apt-get 具体：

$man apt-get
[...]
-y, --yes, --assume-yes
       Automatic yes to prompts; assume "yes" as answer to all prompts
       and run non-interactively. If an undesirable situation,
       such as changing a held package, trying to install a unauthenticated
       package or removing an essential package occurs then apt-get will abort. 
[...]
--force-yes
       Force yes; this is a dangerous option that will cause apt to continue
       without prompting if it is doing something potentially harmful.
       It should not be used except in very special situations.
       Using force-yes can potentially destroy your system!

一般：yes命令：

$man yes
yes - output a string repeatedly until killed [...]
DESCRIPTION
   Repeatedly output a line with all specified STRING(s), or 'y'.

由于yes对apt-get内部结构一无所知，因此它可能相当于--force-yes并因此危险。如果你仍然想这样做，你可以将输出通过管道yes传入apt-get：

yes | apt-get update