mail db_load@seanys.com -s "TESTing" < /home/pi/testemail.txt
echo "testING" | mail -s db_load@seanys.com -s "TESTing"

$ mail db_load@seanys.com -s "TESTing"
Cc:
ING!!!
<ctrl d>

https://www.interserver.net/tips/kb/linux-mail-command-usage-examples/ https://www.binarytides.com/linux-mail-command-examples/