多次使用 sudo 时系统未征得我的同意

Question

当我sudo用来安装某些软件、更新我的系统或任何其他需要我同意的操作时（即说y或n在系统可以继续之前），我只是第一次被要求批准该操作。如果之后我决定sudo再次使用，它不会征求我的同意，而只会执行任务。

所以我的问题是：为什么会这样，我怎样才能让它总是征求我的同意？

Answer 1

从 man sudoers

 sudoers uses time stamp files for credential caching.  Once a user has
 been authenticated, the time stamp is updated and the user may then use
 sudo without a password for a short period of time (5 minutes unless
 overridden by the timeout option). 

 timestamp_timeout
                   Number of minutes that can elapse before sudo will ask
                   for a passwd again.  The timeout may include a frac-
                   tional component if minute granularity is insufficient,
                   for example 2.5.  The default is 5.  Set this to 0 to
                   always prompt for a password.  If set to a value less
                   than 0 the user's time stamp will never expire.  This
                   can be used to allow users to create or delete their
                   own time stamps via ``sudo -v'' and ``sudo -k'' respec-
                   tively.

这意味着您可以运行visudo并添加以下行：

Defaults timestamp_timeout=0

有了这个值，我们可以看到没有凭据缓存：

$ sudo id
[sudo] password for sweh: 
uid=0(root) gid=0(root) groups=0(root)
$ sudo id
[sudo] password for sweh: 
uid=0(root) gid=0(root) groups=0(root)
$