* Read histo from hbook file:
h/file 1 28gev_on_numi.hbk
hrin 12  ! 10000  | put histo 12 in histo 10012
close 1 

* select only part of histogram (not necessary):
h/copy 10012(1:200) 10013

* Dump to vector and then vector fo file:
h/pl 10013 			|check my histograms
vec/creat v(200) 		|200 is number of bin in histogram
h/get/cont 10013 v
v/write v 28gev_numi.txt 	|can put some format specification see manual