擅长:python、mysql、java
<p>当您的<code>/bin/sh</code>是<code>bash</code>时,可能会发生这种情况,因为bash将有效用户id设置为实际用户id,除非在启动时提供<code>-p</code>选项。在</p>
<p>这在<a href="http://www.gnu.org/software/bash/manual/bash.html#Invoked-with-unequal-effective-and-real-UID_002fGIDs" rel="nofollow">documentation</a>中描述:</p>
<blockquote>
<p>If Bash is started with the effective user (group) id not equal to the real user (group) id, and the -p option is not supplied, no startup files are read, shell functions are not inherited from the environment, the SHELLOPTS, BASHOPTS, CDPATH, and GLOBIGNORE variables, if they appear in the environment, are ignored, and the effective user id is set to the real user id. If the -p option is supplied at invocation, the startup behavior is the same, but the effective user id is not reset.</p>
</blockquote>