Add file contents to the staging area. Synonym of git add.
# To add a file to the index:
git stage <path/to/file>
# To add all files (tracked and untracked):
git stage -A
# To only add already tracked files:
git stage -u
# To also add ignored files:
git stage -f
# To interactively stage parts of files:
git stage -p
# To interactively stage parts of a given file:
git stage -p <path/to/file>
# To interactively stage a file:
git stage -i