The -p option in both git-add and git-commit allows you to interactively stage changes.
- y - stage this hunk
- n - do not stage this hunk
- q - quit; do not stage this hunk or any of the remaining ones
- a - stage this hunk and all later hunks in the file
- d - do not stage this hunk or any of the later hunks in the file
- g - select a hunk to go to
- / - search for a hunk matching the given regex
- j - leave this hunk undecided, see next undecided hunk
- J - leave this hunk undecided, see next hunk
- k - leave this hunk undecided, see previous undecided hunk
- K - leave this hunk undecided, see previous hunk
- s - split the current hunk into smaller hunks
- e - manually edit the current hunk
- ? - print help