SSH

apt install -y openssh

Generate SSH key

ssh-keygen -t rsa -b 4096 -C "$(whoami)@$(hostname)-$(date -I)"

without promt

ssh-keygen -t rsa -b 4096 -N '' -f ~/.ssh/id_rsa <<< y

Copy public key

ssh-copy-id -i ~/.ssh/id_rsa.pub user@host -p 22

alternative

cat ~/.ssh/id_rsa.pub | ssh user@host 'cat >> ~/.ssh/authorized_keys'

Execute commands on remote server

ssh user@host "hostname && uptime && date"

alternative

ssh user@host /bin/bash << EOF
  hostname
  uptime
  date
EOF

execute commands on many servers

for s in host1 host2 host3
do
    ssh user@${s} uptime
    ssh user@${s} 'bash -s' < script.sh
done

####

strace -f -F -s1000 -t -T `ps aux | grep -E 'php-fpm' | awk '{print "-p" $2}' | xargs`