from(1)
NAME
from − identifies sender of mail
SYNTAX
from [−f mailbox] [−s sender]
DESCRIPTION
The from command prints out the mail header lines in a mailbox file to show you who has sent mail to you.
OPTIONS
−f mailbox
Uses specified file instead of your normal mail file. If this option is used, but file argument is not specified, read your mbox file.
−s sender
Determines if any new mail from specified user. Prints mail headers for mail sent by specified sender.
FILES
/usr/spool/mail/*