Syntax

• git subtree add -P <prefix> <commit>
• git subtree add -P <prefix> <repository> <ref>
• git subtree pull -P <prefix> <repository> <ref>
• git subtree push -P <prefix> <repository> <ref>
• git subtree merge -P <prefix> <commit>
• git subtree split -P <prefix> [OPTIONS] [<commit>]

Remarks

This is an alternative to using a submodule