如何使用repo管理android

usage: repo COMMAND [ARGS]
The most commonly used repo commands are:
abandon Permanently abandon a development branch
branch View current topic branches
branches View current topic branches
checkout Checkout a branch for development
cherry-pick Cherry-pick a change.
diff Show changes between commit and working tree
diffmanifests Manifest diff utility
download Download and checkout a change
grep Print lines matching a pattern
info Get info on the manifest branch, current branch or unmerged branches
init Initialize repo in the current directory
list List projects and their associated directories
overview Display overview of unmerged project branches
prune Prune (delete) already merged topics
rebase Rebase local branches on upstream branch
smartsync Update working tree to the latest known good revision
stage Stage file(s) for commit
start Start a new branch for development
status Show the working tree status
sync Update working tree to the latest revision
upload Upload changes for code review
See 'repo help ' for more information on a specific command.
See 'repo help --all' for a complete list of recognized commands.