arp -s 192.168.1.43 12:48:08:bb:a5:bb
Make sure the IP address is a valid one in the above command.
The arp utility supports taking entries from a file.
Simply pass the file path as an argument to arp command.
By default the /etc/ethers file is used.
The file content should look like this:
12:f7:fd:48:aa:79 192.168.1.40 12:48:08:aa:a5:bb 192.168.1.43
Now you can give the path of the file as argument.
arp -f /etc/ethers