@DRIVE[filename]: Returns the drive of filename. If the filename parameter doesn't contain a drive specification, @DRIVE will expand filename before the drive is extracted.
filename must be in quotes if it contains white space or special characters.
If the path is a UNC, @DRIVE will return the computer name + sharename.
Examples:
echo @drive["c:\program files\xyz.abc"]
c:
echo "%@drive[\\system1\d_drive\myfile]"
\\system1\d_drive
