man nice 的结果

NAME
       nice - run a program with modified scheduling priority

SYNOPSIS
       nice [OPTION] [COMMAND [ARG]...]

DESCRIPTION
       Run  COMMAND  with  an  adjusted niceness, which affects process scheduling.  With no COMMAND, print the current niceness.  Niceness values
       range from -20 (most favorable to the process) to 19 (least favorable to the process).

       Mandatory arguments to long options are mandatory for short options too.

       -n, --adjustment=N
              add integer N to the niceness (default 10)

The  full documentation for nice is maintained as a Texinfo manual.  If the info and nice programs are properly installed at your site, the
       command

              info coreutils 'nice invocation'

我执行 nice -n -10 service httpd start   的结果为

We are no longer a registered authentication agent.

不过nice这个优先级修改的效果不明显，不要纠结了