### Description

Currently, the `airflow variables export` command requires an explicit file path and does not support output to stdout. However connections can be printed to stdout using `airflow connections export -`. This inconsistency between the two export commands can lead to confusion and limits the flexibility of the variables export command.

### Use case/motivation

To bring some consistency, similar to connections, variables should also be printed to STDOUT, using `-` instead of filename. 

### Related issues

_No response_

### Are you willing to submit a PR?

- [X] Yes I am willing to submit a PR!

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)

ARG_VERBOSE,
        ),
        epilog=(
            "examples:\n"
            "To check if the local scheduler is still working properly, run:\n"
            "\n"
            '    $ airflow jobs check --job-type SchedulerJob --local"\n'
            "\n"
            "To check if any scheduler is running when you are using high availability, run:\n"
            "\n"
            "    $ airflow jobs check --job-type SchedulerJob --allow-multiple --limit 100"
        ),
    ),
)
core_commands: list[CLICommand] = [
    GroupCommand(
        name="dags",
        help="Manage DAGs",
        subcommands=DAGS_COMMANDS,
    ),
    GroupCommand(
        name="tasks",
        help="Manage tasks",
        subcommands=TASKS_COMMANDS,
    ),
    GroupCommand(
        name="pools",
        help="Manage pools",
        subcommands=POOLS_COMMANDS,
    ),