melt provides a set of tools related with fonts, in Go.
$> go get github.com/go-fonts/melt/cmd/otf2otc
$> otf2otc -h
Usage: otf2otc [options] file1.ttf file2.ttf [file3.ttf [...]]
ex:
$> otf2otc -o foo.otc file1.ttf file2.ttf
$> otf2otc -o foo.otc file1.ttf file2.otf file3.otf file4.ttf
options:
-o string
path to output OpenType Collection file (default "out.otc")
$> otf2otc -o out.otc LiberationMono-*.ttf
$> ll out.otc
-rw-r--r-- 1 binet binet 1.2M Jun 17 11:27 out.otc