Linux/Unix useful commands

Find count of files in a folder

ls -l /san1/home/ports/Quest/QuestHL7incoming/new/prod/comite_part1_2xx/ | wc -l

Enable/Disable firewall

CentOS V < 7

service iptables list

service iptables start

service iptables stop

CentOS V >= 7

Status: systemctl status firewalld 

Start: systemctl start firewalld 

Stop: systemctl stop firewalld 

Login to a server without password
run ssh-keygen from source machine will create key stored at ~/.ssh/id_rsa.pub copy the code alone and paste in the destination server > autorised_keys 

/root/.ssh/authorized_keys => if not exists in the destination server, you can create it