The hs extension distribution includes the "hbook2hs" program for
conversion of HBOOK files into Histo-Scope format. Run this program
without any arguments to see its usage instructions. Together with
the "tohbook" program which comes with the Histo-Scope distribution,
this allows for free exchange of data items of certain types between
the two formats. Only similar structures may be converted: 1d histograms,
2d histograms, and ntuples. HBOOK column-wise ntuples and profile
histograms can not be converted to Histo-Scope. Histo-Scope 3d histograms,
triggers, indicators, controls, and groups can not be converted to HBOOK.

The "tohbook" program has some limitations. It can not convert category
structures with depth more than 4. For example, the following category
name is still ok: "c0/c1/c2/c3". However, "c0/c1/c2/c3/c4" will result
in "tohbook" failure. Also, be aware that the names of Histo-Scope
subcategories will be converted by HBOOK to upper case and, if they are
long, truncated to 16 characters. For example, category name
"abc/defghijklmnopqrstuvwx/yz" will be converted to HBOOK directory
"ABC/DEFGHIJKLMNOPQRS/YZ".