arp hostname
arp -a
arp -d hostname
arp -s hostname MAC_address[temp][pub]
arp -f filename

arp displays and modifies the Internet-to-Ethernet address translation tables used by the address resolution protocol (arp(4)).
With no flags, the program displays the current arp entry for hostname.
The host may be specified by name or by number, using Internet dot notation.

-a all

-d hostname super-user can delete an entry

-s hostname ether_addr [temp] Create an arp entry for the host called hostname with the Ethernet address MAC_addr given as six hex bytes separated by colons(ex 00:0A:97:01:FC:12 ).
The entry will be permanent unless the word temp is given in the command.
If the word pub is given, the entry will be "published"; i.e., this system will act as an arp server, responding to requests for hostname even though the host address is not its own.

-f file file to be read and multiple entries to be set in the arp tables. Entries in the file should be of the form

hostname MAC_addr [temp] [pub]

SEE inet(3), arp(4), ifconfig(8)

4.3 Berkeley Distribution April 27, 1995