Output: 
drusepth1:/home/drusepth/Desktop# perl burrows.pl drusepth
DEBUG: $xstring = drusepth
DEBUG: @rotation_box = 1
DEBUG: $xstring = hdrusept
DEBUG: @rotation_box = 2
DEBUG: $xstring = thdrusep
DEBUG: @rotation_box = 3
DEBUG: $xstring = pthdruse
DEBUG: @rotation_box = 4
DEBUG: $xstring = epthdrus
DEBUG: @rotation_box = 5
DEBUG: $xstring = septhdru
DEBUG: @rotation_box = 6
DEBUG: $xstring = usepthdr
DEBUG: @rotation_box = 7
DEBUG: $xstring = rusepthd
DEBUG: @rotation_box = 8

8