How to get rid of Git submodules untracked status?

I found this blog post to work overall. By adding the ignore = dirty option to each one of the entries in the .gitmodules file.

[submodule "zen-coding-gedit3"]
    path = zen-coding-gedit3
    url = git://github.com/leafac/zen-coding-gedit3.git
    ignore = dirty

Since the git status reports untracked content, the actual way to have a clean status would be to go into each one of those submodules and:

• add and commit the untracked contents,
• or reference the untracked contents in a .gitignore specific to each module.
• or you can add the same ignored content to the submodule's .git/info/exclude, as peci1 reports in the comments.

• or add dirty to the submodule specification, as mentioned in ezraspectre's answer (upvoted).

  git config -f .gitmodules submodule.<path>.ignore untracked
  

• or add a global .gitignore file (often ~/.gitignore-global). Like for example .DS_Store or in my case Carthage/Build as reported by Marián Černý in the comments. See .gitginore man page:

Patterns which a user wants Git to ignore in all situations (e.g., backup or temporary files generated by the user’s editor of choice) generally go into a file specified by core.excludesFile in the user’s ~/.gitconfig. Its default value is $XDG_CONFIG_HOME/git/ignore. If $XDG_CONFIG_HOME is either not set or empty, $HOME/.config/git/ignore is used instead.

You can also go to each submodule dir and act as a separated git. For example:

cd my/project/submodule
git status

... /gets the list of modified files/

git add .  //to add all of them to commit into submodule
git commit -m "message to your submodule repo"

you can also update your remote submodule repo with

git submodule update

after all