Command line terminal is a vital tool in all Linux installations, so is on Openmoko smartphones.
The Om 2008.8 (and Om 2008.9 update) does not have a terminal application pre-installed, but the openmoko-terminal2 is available in the default package sources.
To install it, after configuring some kind of networking like for example USB Networking or Wifi, you can use the software installer on the bottom of the screen, or type this one the phone via SSH connection
opkg install openmoko-terminal2
To have a "terminal friendly keyboard", install the illume-config package and reboot. Clicking the strange icon at the new keyboard's corner will let you choose "Terminal" layout. See also Om 2008.8 Keyboard and Keyboard_Debate.