The ps Command

The ps (i.e., process status) command is used to provide information about the currently running processes, including their process identification numbers (PIDs).

Show all Server processes 
ps -ef |grep oracledcpdb1    --here, dcpdb1 is instance name 

Total count of server processes 
ps -ef |grep oracledcpdb1 |grep -v grep |wc -l   ---here, dcpdb1 is instance name

Show background processes 
ps -ef |grep dcpdb1  --here, dcpdb1 is instance name