Most important commands for Linux

-          usermod -aG sudo customer

-          usermod -aG wheel customer   -- add to sudo

-          service --status-all 

-          gzip –d <file name>

-          w

-          who

-          users

-          last

-          finger

-          netstat | grep http | wc –l

-          netstat -ntu | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -n

-          grep -r 'coinhive' *

-          shutdown –rh now

-          killall mysqld

-          kill -9 PID

-          pidof mysqld

-          kill -9 PID1 PID2 PID3

-          pkill mysqld

-          pgrep mysqld

-          cat /etc/redhat-release

-          ps aux|grep mysql

-          screen –r

-          screen –X –S <screen name> quit

-          screen : inside session , click ctrl+A , then quit