mailx

Send and receive mail. More information: https://manned.org/mailx.

• Send mail (the content should be typed after the command, and ended with Ctrl+D):
  mailx -s "{{subject}}" {{to_addr}}
• Send mail with content passed from another command:
  echo "{{content}}" | mailx -s "{{subject}}" {{to_addr}}
• Send mail with content read from a file:
  mailx -s "{{subject}}" {{to_addr}} < {{content.txt}}
• Send mail to a recipient and CC to another address:
  mailx -s "{{subject}}" -c {{cc_addr}} {{to_addr}}
• Send mail specifying the sender address:
  mailx -s "{{subject}}" -r {{from_addr}} {{to_addr}}
• Send mail with an attachment:
  mailx -a {{path/to/file}} -s "{{subject}}" {{to_addr}}