FROM(1) General Commands Manual FROM(1)

from — print names of those who have sent mail

from [-f file] [-s sender] [user]

from prints out the mail header lines from the invoker's mailbox.

The options are as follows:

file
The supplied file is examined instead of the invoker's mailbox. If the -f option is used, the user argument should not be used.
sender
Only mail from addresses containing the supplied string are printed.

If user is given, the user's mailbox is examined instead of the invoker's own mailbox. (Privileges are required.)

from utilizes the LOGNAME, MAIL, and USER environment variables.

If the MAIL environment variable is set, its value is used as the path to the user's mail spool.

/var/mail/*
 

biff(1), mail(1)

The from command appeared in 2BSD.

Bill Joy, 1979.

OpenBSD 7.8 June 2, 2015 FROM(1)