I have use mutt to send mails. It works fine when I use my own user account: e.g. echo "foo bar" | mutt email@example.com
However, when I put the above command in /etc/lightdm/lightdm.conf (I want to receive the mail every time my PC is started), the command will be executed with root account, but the mails I receive has no contents in the email body (no "foo bar" is shown in the mail). How can I echo the contents in mutt when I use root account?