Why git 0.01 doesn't have git-add?

Question

I'm interested in the original version of git. The earliest version I can find is git v0.01 in kernel.org/pub/software/scm/git/. After compiling I get 7 executable file: init-db, read-tree, write-tree, commit-tree, show-diff, update-cache, cat-file.

./init-db 

is similar to git init. It creates a dir named.dircache. But I can find the corresponding command of

git add test.c

How does git 0.01 add files?

Answer 1

use update-cache to add file

./update-cache cat-file.c README

./show-diff
README: ok
cat-file.c: ok