The dvc add command is used to add changed files to the index in the DVC (Data Version Control) system. The index contains information about the files that are tracked by DVC and their versions. By adding files to the index, you are telling DVC to track changes to those files and include them in the version control system.

Use case 1: Add a single target file to the index

Code:

dvc add path/to/file

Motivation: If you have made modifications to a specific file and want to track its changes, you can use this command to add the file to the DVC index. This ensures that any subsequent changes made to the file will be tracked and versioned.

Explanation: The command dvc add is followed by the path to the file you want to add to the index. In this use case, path/to/file specifies the location of the target file. DVC will then add the file to the index and start tracking its changes.

Example Output:

Adding 'path/to/file' to '.dvc/cache'.
100% Add|███████████████████████████████|1/1 [00:00, 605.84file/s]

Use case 2: Add a target directory to the index

Code:

dvc add path/to/directory

Motivation: If you have multiple files within a directory that you want to track and version, you can use this command to add the entire directory to the DVC index. This makes it convenient to manage a group of related files together.

Explanation: Similar to the previous use case, the dvc add command is used followed by the path to the directory you want to add to the index. In this use case, path/to/directory specifies the location of the target directory. DVC will add all the files within the directory to the index and start tracking their changes.

Example Output:

Adding 'path/to/directory' to '.dvc/cache'.
100% Add|███████████████████████████████|5/5 [00:00, 250.84file/s]

Use case 3: Recursively add all the files in a given target directory

Code:

dvc add --recursive path/to/directory

Motivation: If you have a directory with multiple nested subdirectories and you want to add all the files within the entire directory structure to the DVC index, you can use this command. This saves the effort of manually adding each file individually.

Explanation: In this use case, the dvc add command is used with the --recursive flag, followed by the path to the directory you want to add recursively. The --recursive flag tells DVC to recursively add all the files within the specified directory and its subdirectories to the index.

Example Output:

Adding 'path/to/directory' and its subdirectories to '.dvc/cache'.
100% Add|███████████████████████████████|10/10 [00:00, 333.33file/s]

Use case 4: Add a target file with a custom .dvc filename

Code:

dvc add --file custom_name.dvc path/to/file

Motivation: By default, when you add a file to the DVC index, a corresponding .dvc file is created with the same name as the target file. However, there might be scenarios where you want to specify a custom filename for the .dvc file. This can be useful if you want to preserve the original filename for the target file.

Explanation: In this use case, the dvc add command is used with the --file flag, followed by the desired custom filename for the .dvc file and the path to the target file. This command allows you to add a target file to the DVC index and specify a custom filename for the corresponding .dvc file.

Example Output:

Adding 'path/to/file' to 'custom_name.dvc'.
100% Add|███████████████████████████████|1/1 [00:00, 333.33file/s]

Conclusion:

The dvc add command is a powerful tool for adding files and directories to the DVC index. By using the command and its various options, you can track and version changes to your data files effectively. Whether you want to add individual files, entire directories, or even recursively add files within a directory structure, the dvc add command provides the flexibility to meet your versioning needs.