Serial Port Access for non-sudo User
Working with embedded devices often requires serial access. By default linux tty ports require super user access, so when running an application like a serial communications parser, you will want to give access to the user rather than require your application to have sudo powers.
Once you know which user(s) are to require access, add them to dialout ant tty.
sudo usermod -a -G dialout <serial-user>
sudo usermod -a -G tty <serial-user>
Dialout is a group, so the user changes will take effect after reboot.
Password Hash
Embedded devices will often need a password hash.
- etc/shadow stores passwords as a hash
- Ubuntu’s autoinstall requires user passwords as a hash
Use mkpasswd to generate a hash. First use the -m help option to see what hash algorithms are available.
$ mkpasswd -m help
Available methods:
sha512crypt SHA-512
sha256crypt SHA-256
md5crypt MD5
descrypt standard 56 bit DES-based crypt(3)
Then generate the hash.
$ mkpasswd -m sha512crypt
Password:
$6$IPKp8j6a8R$2S1SZigM5x.mupPNX50y0/.mhoJ42LSEe80wszpI6L5jiq4oEUPH9A73zAyT3BqJQm1HIk1p9kI3H.eimTMxY.
Center Ubuntu/Gnome Background
If the image you set as your background does not fit into the screen layout, likely it will be stretched or cropped. To center the image, effectively shrinking it execute on command line
$ gsettings set org.gnome.desktop.background picture-options 'centered'
Explanation and details: https://askubuntu.com/questions/1111201/background-image-resize-in-ubuntu-18-04-1-lts