When I initially developed this tool it was because I wanted something faster then file(1). Now it's a library with Tcl binding and soon Python.
I guess advertising it as a faster tool was a mistake, but the concept of nicko (groups, short output) is good for scripting. it's fast and simple and the library is portable across unices.
Anyway thanks for the feedback!.
If you want to quickly measure (file-nicko):
$ time file -e elf /usr/bin/*
$ time nicko /usr/bin/*
On my system:
file(1):
real 0m1.254s user 0m1.049s sys 0m0.184s
nicko(1):
real 0m0.028s user 0m0.010s sys 0m0.014s.