What will the command kill -HUP 1354 do?

The same as kill -SIGHUP 1354
2. The same as kill -1 1354

Kill command is used to terminate the processes by default it sends the TERM signal. When you send the -HUP signal, it will restart the process by reading the original configuration file. It is same to -SIGHUP and -1 signal. If you want to display all the signal avaialbles just use the kill -l command.