How to see if a process/service is started

We generally need to understand the state of our processes under Linux.
Let's take MySQL for example

Service MYSQLD Status

[Root@vm_57_70_centos ~]# service mysqld status;
MYSQLD (PID  17239) is running
... [Root@vm_57_70_centos ~]# 

I am here to start the state, you can see the PID

Chkconfig–list + your Service

[Root@vm_57_70_centos ~]# chkconfig--list mysqld;
Mysqld          0:off   1:off   2:on    3:on    4:on 5:on 6:off

Can see is started, there is on state

Pidof + your Service

[Root@vm_57_70_centos ~]# pidof mysqld
17239
[Root@vm_57_70_centos ~]# 

Can see the PID, description, at this time, the MySQL service is running, if not run, there is no output

Ps-ef | grep + your Service

Can be viewed through NETSTAT-TANP

If there is, there will be MySQL on the top of this article

OK, here are a few common ways to view the process and choose one that you like.