Linux

How to create a systemd service?

Application:

$ cat myapp.sh

#!/usr/bin/bash

echo "I'm a test app" > /tmp/test.file

Service:

$ cat /etc/systemd/system/myapp.service

...

After=network.target

After=mysqld.service

Restart=on-failure

RestartSec=1

Start the service:

$ sudo systemctl start myapp

Start on boot:

$ sudo systemctl enable myapp

How to disable beep speaker?

# temporary

$ sudo rmmod pcspkr

# permanently

$ sudo gedit /etc/modprobe.d/blacklist

    blacklist pcspkr

$ reboot

SSH by key

$ ssh-keygen -t ed25519 -C "new"

$ cat ~/.ssh/config

Host x.x.x.x

  HostName x.x.x.x

  IdentityFile ~/.ssh/new

  IdentitiesOnly yes

  User root

  Port 22

$ ssh x.x.x.x