To determine whom mail is from.
The from command displays the message headings in your mailbox file to show you whom mail is from. If you specify user, the user mailbox is examined instead of your own (provided that you have read permission to user's mailbox).
| Item | Description | 
|---|---|
| -d Directory | Specifies the system mailbox directory. | 
| -s Sender | Prints message headers only for mail sent by Sender. | 
| Item | Description | 
|---|---|
| user | Specifies the user mailbox that is examined instead of your own (provided that you have read permission to the user's mailbox). | 
fromfrom -s dale
In this example, only the message headings of the messages sent from user dale are displayed.from   dawnfrom -d /var/spool/mail -s jane bob| Item | Description | 
|---|---|
| /var/spool/mail/* | System mailboxes for all users. | 
| /usr/bin/from | User mailbox files. |