Unity dash - is there a command line (CLI) interface to perform a search?

Here is a script that might be helpful:

#!/bin/bash
for desktopFile in $(grep -irl "$1" /usr/share/applications/) ; do 
  grep --color=never 'Name=' "$desktopFile" 
  grep --color=never 'Exec=' "$desktopFile" 
  echo ''
done

Assuming you saved it as "searchapps", this is what it does:

$ searchapps disks
Name=Disk Image Writer
Exec=gnome-disks --restore-disk-image %U

Name=Disks
Exec=gnome-disks

Note that there might be other folders you'd like to search in addition to /usr/share/applications. You'd have to modify the script accordingly.