function substring,x,model


bx=byte(x)
bm=byte(model)

ind=where(bx eq bm(0))

Nx= n_elements(bx)
Nm= n_elements(bm)

if ind(0) lt 0 or ind(0) gt Nx-Nm then return,-1L



	for j=0L,n_elements(ind)-1 do begin

if ind(j) gt Nx-Nm then return,-1L

if equiv(bx(ind(j):ind(j)+Nm-1),bm) then begin
if n_elements(Found) le 0 then Found=ind(j) else Found=[Found,ind(j)]
endif

	endfor

if n_elements(Found) le 0 then Found=-1L

return,Found

	end