kill a process by its name
PROCESS_NAME=ABC
pid=`ps -ef | grep $PROCESS_NAME | grep -v grep | awk '{print $2}'`
kill -9 $pid
start a process as deamon
nohup ./NAME &
find a file
sudo updatedb
locate filename
lookup network connections
ss -ntlp
ss -nulp
ss -antp
netstat -tnlp
netstat -nulp
lookup process
ps -ef | grep PROCESS
test network
# test tcp port
telnet host port
ping host
DNS lookup
dig abc.com
dig abc.com @223.5.5.5
stop a process
kill -9 $pid