notebook/IT/git/submodule.md

# submodule

Git submodule allows ro add externel repository in a repository

## Adding submodule

- ```git submodule add http://git/toto.git $path```
 this command add *<http://git/toto.git>* in *path* directory (add -b $branchname to follow specific branch)
- after that you need to add and commit submodule folder

to populate a submodule nested in other submodule

- ```git submodule init```
- ```git submodule update```

## removing submodule

- remove submodule entry in *.gitmodules*
- remove submodule entry in *.git/config* (only present when **git submodule init** have been perform)
- remove submodule path ```git rm --cached $path```

## Updating submodule

you can update a submodule Manually going in submodule folder and perform a ```git fetch``` and ```git merge```

### Fetch and merge

automatic process

- perform a ```git submodule update --remote```

in  each case you need to commit update in project