Hddtemp is a utlity that reports hard disk temperature. It comes with a lightweight daemon to provide the information of a local port.
Sync and install with pacman:
# pacman -S hddtemp
Start the daemon:
# /etc/rc.d/hddtemp start
Add the daemon to the DAEMONS array in /etc/rc.conf to facilitate auto-start on boot:
# DAEMONS=(coretemp it87 ... hddtemp ...)
Hddtemp can be invoked with the drive as the argument:
# hddtemp /dev/sd[x]
Where x is the drive.
Another way to get the temperature is by connecting to the daemon which is listening on port 7634.
# telnet localhost 7634
Or with netcat:
# nc localhost 7634
For other information like hard drives supported, logging e.t.c. refer to the manpage:
# man hddtemp
Hddtemp can be easily integrated with system monitors like Conky or the GNOME sensors applet.