why git status shows "working directory clean" even after I add a new file

Question

$ git --version
git version 2.5.3

$ git branch
* feature/branchABC

$ git status -b branchABC
On branch feature/branchABC
Your branch is up-to-date with 'origin/feature/branchABC'.
nothing to commit, working directory clean

$ echo "abc" > abc.cpp

$ git status -b branchABC
On branch feature/branchABC
Your branch is up-to-date with 'origin/feature/branchABC'.
nothing to commit, working directory clean

Question> After I add a new file abc.cpp in the current folder, why I still see the message 'working directory clean` in git?

Thank you

--Update One--

$ git status
On branch feature/branchABC
Your branch is up-to-date with 'origin/feature/branchABC'.
Untracked files:
  (use "git add <file>..." to include in what will be committed)

        abc.cpp

nothing added to commit but untracked files present (use "git add" to track)

Answer 1

the command git status doesn't require an argument. The argument branchABC that you provided is interpreted by git-status as a path. So git checks the status of a file or directory named branchABC. Solution: just use one of the following commands:

git status
git status -b

in the git-status man page: git status [<options>...] [--] [<pathspec>...], and since branchABC is not a valid option; it is interpreted as pathspec. I agree that maybe git could have put a warning that there is nothing matching the path branchABC...

I tested this locally.

$ git status
# On branch test
# Untracked files:
#   (use "git add <file>..." to include in what will be committed)
#
#       spec/a
#       src/a

$ git status src
# On branch test
# Untracked files:
#   (use "git add <file>..." to include in what will be committed)
#
#       src/a

$ git status non-existing-path
# On branch test
nothing to commit, working directory clean