I have been learning how to use postfix to end email using the command line, which I find helpful when at work and I don't want to open a browser or switch to mouse, to send an email about my broken stuff to system admin. I've been practicing from my laptop.
Ubuntu uses postfix, and I found the file /etc/postfix/main.cf
The default is for sent mail to be $USER@$mydomain, so at this point I have: $USER@gmail.com as the sender when I check my gmail account.
I can't figure out how to get another name other than $USER, such as my regular gmail name, so people can respond to my gmail account.