Depending on the recording app installed, that could be done by calling the corresponding activity via the am (activity manager). The syntax for this is explained on the ADB help page:
start [options] <INTENT>
Example given:
am start -a android.intent.action.VIEW
This means, you first have to find the corresponding intent. This can be done using any Manifest browser (there are several apps available), or e.g. using the activity browser integrated with Apex Launcher (long-tap free space on homescreen, select Shortcut, then Activity). The am call then can either be initiated from within a terminal in the way described above, or via ADB by prefixing the call with adb shell, e.g. adb shell am start -a android.intent.action.VIEW.
See also: http://en.androidwiki.com/wiki/ADB_Shell_Command_Reference