==================================
Transferring Files
==================================

This section explains how to transfer files between the supercomputing system and your PC.
It is assumed that :doc:`/getting_started/login_to_system` has already been completed.

File Transfer Using sftp
========================

Files are transferred using the ``sftp`` command from "Command Prompt" on Windows, or "Terminal" on macOS and Linux.

.. code-block:: none

   $ sftp super.sc.imr.tohoku.ac.jp
   Enter passphrase for key ‘/home/pc-user/.ssh/keys/id_rsa’:
   sc-user@super.sc.imr.tohoku.ac.jp's password:
   Connected to super.sc.imr.tohoku.ac.jp.
   sftp>

Unless specified otherwise, the remote directory is the user's home directory.

The basic commands are described below.

.. list-table::
   :widths: 30 70
   :header-rows: 1

   * - Command
     - Function
   * - ``ls [directory_name]``
     - Displays the contents of the remote (destination) directory.
   * - ``cd [directory_name]``
     - Changes the remote current directory.
   * - ``lls [directory_name]``
     - Displays the contents of the local (source) directory.
   * - ``lcd [directory_name]``
     - Changes the local current directory.
   * - ``put [file_name]``
     - Transfers a local file to the remote current directory.
   * - ``put -r [directory_name]``
     - Transfers a local directory to the remote current directory.
   * - ``get [file_name]``
     - Transfers a remote file to the local current directory.
   * - ``get -r [directory_name]``
     - Transfers a remote directory to the local current directory.
   * - ``help``
     - Displays sftp usage and help.
   * - ``exit``
     - Terminates the connection.

.. attention::

   When transferring files with the ``put`` or ``get`` commands, if a file with the same name already exists at the destination, it will be overwritten.

Below are some usage examples.

* Transferring a file named ``test.txt`` in the local current directory to the remote host:

.. code-block:: none

   sftp> put test.txt
   Uploading test.txt to /home/sc-user/test.txt
   test.txt                                        100%   16     0.8KB/s   00:00
   sftp>

* Copying a directory named ``test`` in the remote current directory to the local host:

.. code-block:: none

   sftp> get -r test
   Fetching /home/sc-user/test/ to test
   Retrieving /home/sc-user/test
   /home/sc-user/test/test1.txt                    100% 1855    39.0KB/s   00:00
   /home/sc-user/test/test2.txt                     100%  354     6.3KB/s   00:00
   sftp>


File Transfer Using rsync
=========================

Files are transferred using the ``rsync`` command from Windows Subsystem for Linux (WSL) on Windows, or "Terminal" on macOS and Linux.

* Example: Downloading files from the supercomputer to a PC:

.. code-block:: none

   $ rsync -auvHAS --stats sc-user@super.sc.imr.tohoku.ac.jp:/home/sc-user/source_directory /destination_directory
   Enter passphrase for key ‘/home/pc-user/.ssh/keys/id_rsa’: your_ssh_passphrase
   password: your_password
   receiving incremental file list
   ...

* Example: Uploading files from a PC to the supercomputer:

.. code-block:: none

   $ rsync -auvHAS --stats /source_directory sc-user@super.sc.imr.tohoku.ac.jp:/home/sc-user/destination_directory
   Enter passphrase for key ‘/home/pc-user/.ssh/keys/id_rsa’: your_ssh_passphrase
   password: your_password
   sending incremental file list
   ...

The options used in the above examples are described below. For details, please refer to the rsync manual.

.. list-table::
   :widths: 30 70
   :header-rows: 1

   * - Option
     - Function
   * - ``-a`` , ``--archive``
     - Preserves attributes (archive mode)
   * - ``-u`` , ``--update``
     - Transfers only files that have been updated
   * - ``-v`` , ``--verbose``
     - Displays detailed execution progress
   * - ``-H`` , ``--hard-links``
     - Preserves hard links
   * - ``-A`` , ``--acls``
     - Preserves Access Control Lists (ACLs)
   * - ``-S`` , ``--sparse``
     - Handles sparse files efficiently
   * - ``--stats``
     - Displays transfer statistics (number of files, transfer size, etc.) after completion


References
==========

* :doc:`/login/how_to_file_transfer`