Warning: bad syntax, perhaps a bogus ‘-‘? See /usr/share/doc/procps-3.2.7/FAQ

root@oracledb ~]# ps -aux | grep 100  
Warning: bad syntax, perhaps a bogus '-'? See /usr/share/doc/procps-3.2.7/FAQ
root      2969  0.0  0.0  61092   708 pts/0    S+   12:15   0:00 grep 100


根据/usr/share/doc/procps-3.2.7/FAQ文件所述
[root@oracledb ~]# more /usr/share/doc/procps-3.2.7/FAQ
Why does "ps -aux" complain about a bogus '-'?

According to the POSIX and UNIX standards, the above command asks to display
all processes with a TTY (generally the commands users are running) plus all
processes owned by a user named "x". If that user doesn't exist, then ps will
assume you really meant "ps aux". The warning is given to gently break you of a
habit that will cause you trouble if a user named "x" were created.

正确格式为：
[root@oracledb ~]# ps aux  | grep 100 
root      2579  0.0  0.0  61088   704 pts/0    S+   12:08   0:00 grep 100