什么是＆＆意味着什么？
这个问题在这里已经有了答案：
让我们来看看man bash ：
Redirecting Standard Output and Standard Error
This construct allows both the standard output (file descriptor 1) and the stan‐
dard error output (file descriptor 2) to be redirected to the file whose name is
the expansion of word.
There are two formats for redirecting standard output and standard error:
&>word
and
>&word
Of the two forms, the first is preferred. This is semantically equivalent to
>word 2>&1
换句话说， >& /dev/null从命令中抑制输出和错误/信息性消息。