https://www.tecmint.com/send-email-attachment-from-linux-commandline/
https://stackoverflow.com/questions/17359/how-do-i-send-a-file-as-an-email-attachment-using-linux-command-line
https://unix.stackexchange.com/questions/223636/sendmail-attachment
https://tecadmin.net/ways-to-send-email-from-linux-command-line/
