$ cue help inputs
Many commands apply to a set of inputs:

cue <command> [inputs]

The list [inputs] may specify CUE packages, CUE files, non-CUE
files or some combinations of those. An empty list specifies
the package in the current directory, provided there is a single
named package in this directory.

CUE packages are specified as an import path. An import path
that begins with a "." or ".." element is a relative import path,
is interpreted as a file system path, and denotes the
package instance in that directory.

Otherwise, the import path P is absolute and denotes a package that
may be external, usually found in an external registry. It may also
refer to a package in cue.mod/{pkg|gen|usr}/P - this is legacy
behavior that might be removed at a later date.

An absolute import path is of the form P or P@vN where vN is the major
version of the module containing the package. An import path is mapped
to a registry location by consulting cue.mod/module.cue and the
registry configuration (see "cue help modules" and "cue help
registryconfig" for more details).

An import may contain a ":name" suffix to indicate a specific
package to load within a given path. It is necessary to specify this
when there is more than one package at the path.

For example, the following import path specifies a package
named "other" in some external module with major version v1.

	foo.example/bar/baz@v1:other

A local import path may contain one or more "..." to match any
subdirectory: pkg/... matches all packages below pkg, including pkg
itself, while foo/.../bar matches all directories named bar within
foo. In all cases, directories containing cue.mod directories are
excluded from the result. "..." is not currently supported in external
import paths.

Directory and file names that begin with "." or "_" are ignored,
unless explicitly listed as inputs. File with names ending "_tool.cue"
are ignored unless running "cue cmd" and they are in packages
explicitly mentioned on the command line. Files with names ending
"_test.cue" are ignored for the time being; they are reserved for
future testing functionality.

A package may also be specified as a list of .cue files.
The special symbol '-' denotes stdin or stdout and defaults to
the cue file type for stdin. For stdout, the default depends on
the cue command. A .cue file package may not be combined with
regular packages.

Non-cue files are interpreted based on their file extension or,
if present, an explicit file qualifier (see the "filetypes"
help topic). By default, all recognized files are unified at
their root value. See the "filetypes" and "flags" help topics
on how to treat each file individually or how to combine them
differently.

If a data file has multiple values, such as allowed with JSON
Lines or YAML, each value is interpreted as a separate file.

If the --schema/-d is specified, data files are not merged, and
are compared against the specified schema within a package or
non-data file. For OpenAPI, the -d flag specifies a schema name.
For JSON Schema the -d flag specifies a schema defined in
"definitions". In all other cases, the -d flag is a CUE
expression that is evaluated within the package.

Examples (also see also "flags" and "filetypes" help topics):

# Show the definition of each package named foo for each
# directory dir under path.
$ cue def ./path/.../dir:foo

# Unify each document in foo.yaml with the value Foo in pkg.
$ cue export ./pkg -d Foo foo.yaml

# Unify data.json with schema.json.
$ cue export data.json schema: schema.json