ApplyLayer parses a diff in the standard layer format from `layer`, and applies it to the directory `dest`.

Compare two directories and generate an array of Change objects describing the changes.

CmdStream executes a command, and returns its stdout as a stream.

CopyFileWithTar emulates the behavior of the 'cp' command-line for a single file.

CopyWithTar creates a tar archive of filesystem path `src`, and unpacks it at filesystem path `dst`.

NewTempArchive reads the content of src into a temporary file, and returns the contents of that file as an archive.

Tar creates an archive from the directory at `path`, and returns it as a stream of bytes.

Tar creates an archive from the directory at `path`, only including files whose relative paths are included in `filter`.

TarUntar is a convenience function which calls Tar and Untar, with the output of one piped into the other.

Untar reads a stream of bytes from `archive`, parses it as a tar archive, and unpacks it into the directory at `path`.

UntarPath is a convenience function which looks for an archive at filesystem path `src`, and unpacks it at `dst`.