| Option group controlling copy_file function effects for existing target files | ||
| Constant | Meaning | |
| none | (Default) Error; file already exists. | |
| skip_existing | Do not overwrite existing file, do not report an error. | |
| overwrite_existing | Overwrite the existing file. | |
| update_existing | Overwrite the existing file if it is older than the replacement file. | |
| Option group controlling copy function effects for subdirectories | ||
| Constant | Meaning | |
| none | (Default) Do not copy subdirectories. | |
| recursive | Recursively copy subdirectories and their contents. | |
| Option group controlling copy function effects for symbolic links | ||
| Constant | Meaning | |
| none | (Default) Follow symbolic links. | |
| copy_symlinks | Copy symbolic links as symbolic links rather than copying the files that
    they point to. | |
| skip_symlinks | Ignore symbolic links. | |
| Option group controlling copy function effects for choosing the form of copying | ||
| Constant | Meaning | |
| none | (Default) Copy content. | |
| directories_only | Copy directory structure only, do not copy non-directory files. | |
| create_symlinks | ||
| create_hard_links | Make hard links instead of copies of files. | |