Linux to Linux: File Transfer Between Two Linux Systems

Transferring files between Linux systems is a common task in local network environments, development setups, and server maintenance. Whether you are copying backups, sharing documents, or syncing project files, Linux provides several tools for efficient and secure file transfer.

This tutorial will show how to transfer files between two Linux systems using different tools.

Prerequisites

• Two Linux systems that can reach each other.
• Access to the command line (terminal) on each system.
• Sudo or root privileges (required for certain tools).

Important Considerations Before Transferring Files Between Two Linux Systems

Before transferring files between two Linux systems, ensure the environment is configured correctly. A successful file transfer depends on network visibility, authentication setup, and the chosen method.

Use the checklist below to prepare both systems:

• Check IP addresses on both systems with the ip and hostname commands. Use ip a or hostname -I to identify IP addresses and confirm network access.
• Verify network connectivity. Use the ping command to confirm the systems can reach each other. For example:

ping [remote_ip_address]

• Confirm SSH access if required. Tools like scp, sftp, and rsync use SSH to connect to the remote system. Test with:

ssh [username]@[remote_ip_address]

• Check for required services or daemons. Some methods need server software running on the destination machine. For example:
  • FTP. Requires an FTP server.
  • Samba. Requires the Samba service.
  • Web-based sharing. Requires Python or third-party tools.
• Open the necessary firewall ports. Make sure UFW or firewalld allows traffic for the chosen protocol. For example, port 22 for SSH, 21 for FTP, or 445 for Samba.
• Ensure proper permissions on source and destination paths. The user account running the transfer must have read access to the source file and write access to the target directory.
• Decide on the best transfer method. Choose based on security, speed, ease of use, and tool availability. For example, SSH-based tools are often preferred for secure, encrypted transfers.

How to Transfer Files Between Two Linux Systems

Linux provides several methods for transferring files between systems. However, some tools are built into most distributions, while others require setting up additional services.

In the following examples, we use two Ubuntu systems on the same network:

• Primary (local) system. The first machine, sara-pnap@pnap (IP: 192.168.56.103), acts as the source of files for transfer.
• Secondary (remote) system. The second machine, pnap-test@pnap-test (IP: 192.168.56.104), acts as the destination for receiving files.

The examples below demonstrate how to use each method in real-world scenarios.

Transfer Files via scp

The scp command (Secure Copy) is used to transfer files between systems over SSH. It works similarly to the cp command. However, instead of copying files locally, scp transfers them securely over the network and encrypts both the file contents and authentication.

The command is suitable for simple, one-time file transfers, especially when setting up persistent sync tools like rsync is unnecessary.

The following steps explain how to transfer files using scp between two Linux systems.

Step 1: Create a Sample File to Transfer

On the primary system, use echo to create a sample file to use in the transfer:

echo "Test file for scp transfer" > /home/sara-pnap/Documents/sample.txt

The command has no output but creates a text file named sample.txt in the Documents directory.

Step 2: Verify the Sample File Exists

Check that the file was created successfully with ls:

ls -l /home/sara-pnap/Documents/sample.txt

Step 3: Ensure SSH is Enabled on Both Systems

The receiving system must have the SSH service running. Therefore, check the status with:

sudo systemctl status ssh

The command confirms the SSH service is running. If it's not, start and enable it with:

sudo systemctl enable --now ssh

Step 4: Transfer a File from the Local System to a Remote System

Use scp to send a file from the primary system to the secondary system:

scp /home/sara-pnap/Documents/sample.txt [email protected]:/home/pnap-test/

Enter the password when prompted. The file appears in the remote user's Home directory

Step 5: Transfer a File from the Remote System to the Local System

To copy the same file back from the secondary system to the primary system, run the following:

scp [email protected]:/home/pnap-test/sample.txt /home/sara-pnap/Desktop/

This places the file in the Desktop directory on the local machine.

Step 6: Transfer a Directory

Use mkdir to create a test directory with sample content:

mkdir /home/sara-pnap/Projects

echo "Test project file" > /home/sara-pnap/Projects/test.txt

Transfer the directory to the remote machine using the -r flag:

scp -r /home/sara-pnap/Projects [email protected]:/home/pnap-test/

This command copies the entire Projects directory and its contents to the remote Home directory.

Transfer Files via rsync

The rsync command is a powerful tool for synchronizing files and directories between systems over SSH. Furthermore, it provides more flexibility than scp, including incremental transfers, compression, and options to preserve file metadata.

Consequently, this method is suitable for recurring transfers or large datasets, especially when changes are frequent and efficiency matters.

The following steps explain how to transfer files using rsync between two Linux systems.

Step 1: Create a Sample File to Transfer

On the primary system, create a file for transfer:

echo "Test file for rsync transfer" > /home/sara-pnap/Documents/rsync-test.txt

The command creates a file in the Documents directory.

Step 2: Ensure rsync is Installed

Check whether rsync is available on both systems:

rsync --version

In this case, the command is installed. If rsync is missing, install it with:

sudo apt install rsync

Step 3: Transfer a File to the Remote System

Use rsync to send the file from the primary to the secondary system:

rsync /home/sara-pnap/Documents/rsync-test.txt [email protected]:/home/pnap-test/

The command produces no output, but transfers the file over SSH, thereby preserving timestamps and permissions.

Step 4: Transfer a File from the Remote System to the Local System

To copy the file back to the primary system, run:

rsync [email protected]:/home/pnap-test/rsync-test.txt /home/sara-pnap/Desktop/

The file appears in the Desktop directory on the primary system. However, there is no output.

Step 5: Transfer a Directory

Create a sample directory and file:

mkdir /home/sara-pnap/Projects-rsync
echo "Rsync project file" > /home/sara-pnap/Projects-rsync/file1.txt

Transfer the entire directory with:

rsync -r /home/sara-pnap/Projects-rsync [email protected]:/home/pnap-test/

Transfer Files via FTP

File Transfer Protocol (FTP) is a standard network protocol used to transfer files between systems over a TCP-based network. However, by default, it is not encrypted.

For the transfer to work, one machine must run an FTP server to receive files, and the other connects to it as a client. This example uses vsftpd, a secure and lightweight FTP server commonly used on Linux systems.

The following steps demonstrate a basic FTP file transfer between two Linux systems.

Step 1: Create a Sample File to Transfer

On the primary system, create a text file to upload via FTP:

echo "FTP test file" > /home/sara-pnap/Documents/ftp-test.txt

The file is created in the local user's Documents directory.

Step 2: Install the FTP Server

On the secondary system, install the vsftpd package:

sudo apt install vsftpd

Step 3: Allow FTP Traffic Through Firewall

Enable incoming FTP connections through the UFW firewall on the secondary system:

sudo ufw allow 21/tcp

This command opens port 21, which FTP uses by default.

Step 4: Connect to the FTP Server from the Client

From the primary system, connect using the ftp command:

ftp 192.168.56.104

When prompted, enter the credentials for the remote system.

Step 5: Upload a File to the FTP Server

After logging in, upload the sample file with the put command:

put /home/sara-pnap/Documents/ftp-test.txt ftp-test.txt

This transfers the file to the remote user's Home directory and saves it as ftp-test.txt.

Step 6: Download a File from the FTP Server

To retrieve a file from the FTP server, use the get command:

get ftp-test.txt

This command downloads the file to the current working directory on the local system.

Transfer Files via sftp

Secure File Transfer Protocol (SFTP) is a secure alternative to FTP that runs over SSH. It encrypts both commands and data, which provides confidentiality and integrity.

Therefore, use SFTP to transfer files between Linux systems when SSH access is available.

Step 1: Create a Sample File to Transfer

On the primary system, create a file:

echo "SFTP test file" > /home/sara-pnap/Documents/sftp-test.txt

Step 2: Connect to the Remote System Using SFTP

From the primary system, start an SFTP session to the secondary system:

sftp [email protected]

Enter the password when prompted.

Step 3: Upload a File to the Remote System

In the SFTP prompt, upload the file:

put /home/sara-pnap/Documents/sftp-test.txt

This transfers the file to the remote user's Home directory.

Step 4: Download a File from the Remote System

Download the file with the get command:

get sftp-test.txt

The file downloads to the current working directory on the primary system.

Step 5: Transfer a Directory

Directory transfers via SFTP use the same syntax, but with the -r flag.

For example, upload a directory named Test from the local system with this command:

put -r /home/sara-pnap/Documents/Test

Transfer Files via Samba

Samba primarily enables file sharing between Linux and Windows systems using the SMB/CIFS protocol.

However, on Linux-to-Linux networks, Samba is used to create persistent shared directories accessible by multiple systems with proper permissions. This method is suitable for collaborative projects or when ongoing access to shared data is required.

The recommended method to transfer files using Samba is to mount the share with the mount -t cifs command. Follow the steps in the sections below to set up the share and complete the transfer.

Step 1: Install Samba on the Secondary System

On the secondary system, update packages and install Samba:

sudo apt install samba

Step 2: Create a Shared Directory

Create a directory to share and use chmod to set permissions:

mkdir -p /home/pnap-test/Shared

chmod 777 /home/pnap-test/Shared

The chmod command gives full read, write, and execute permissions to everyone. The commands have no output.

Step 3: Configure the Samba Share

Open the Samba configuration file using a text editor. To do it with Nano, run:

sudo nano /etc/samba/smb.conf

Add the following section at the end of the file:

[Shared]
   path = /home/pnap-test/Shared
   browsable = yes
   read only = no
   guest ok = no
   valid users = sambauser

Save and exit the editor.

Step 4: Restart Samba

Restart the Samba service to apply changes:

sudo systemctl restart smbd

Step 5: Allow Firewall Access

Allow Samba traffic through the firewall:

sudo ufw allow 'Samba'

Step 6: Access the Samba Share from the Primary System

Install required client utilities with:

sudo apt install cifs-utils smbclient

Step 7: Create a Samba Credentials File

To avoid exposing the Samba username and password in the terminal or shell history, create a credentials file with the following content:

sudo nano /etc/samba-creds

Add the following lines:

username=sambauser
password=samba123

Set strict permissions on the file to protect credentials:

sudo chmod 600 /etc/samba-creds

This ensures only the root user can read or write the file, which is important because the file contains plaintext credentials. Consequently, this file is later used by the mount command to authenticate securely.

Step 8: Transfer a File Through Samba Share

Create a sample file locally on the primary system:

echo "Sample Samba transfer file" > /home/sara-pnap/Documents/samba-sample.txt

Create a mount point and mount the Samba share:

sudo mkdir -p /mnt/samba
sudo mount -t cifs //192.168.56.104/Shared /mnt/samba -o credentials=/etc/samba-creds,vers=3.0

The commands provide no output.

Copy the sample file to the mounted Samba share using cp:

cp /home/sara-pnap/Documents/samba-sample.txt /mnt/samba/

When finished, unmount the share:

sudo umount /mnt/samba

Transfer Files via Web-based Sharing

Web-based file sharing offers multiple methods for transferring files between Linux systems using standard web protocols. Among these, common approaches include HTTP file servers, WebDAV, and cloud storage solutions.

However, for quick, simple transfers without complex setup, Python's built-in HTTP server is effective and widely supported. To transfer a file this way, take the following steps:

Step 1: Create a Sample File to Share

On the primary system, create a test file:

echo "Sample file for web-based sharing" > /home/sara-pnap/Documents/web-share-sample.txt

Step 2: Ensure Python is Installed on the Primary Machine

Verify the primary machine has Python installed with:

python3 --version

If Python is missing, install it with:

sudo apt install python3

Step 3: Start an HTTP Server

Navigate to the directory with the file using cd and launch Python's HTTP server:

cd /home/sara-pnap/Documents
python3 -m http.server 8000

This starts an HTTP server on port 8000 in the current directory.

Step 4: Download the File from the Secondary System

On the secondary system, download the file using curl or wget. For example, with curl:

curl -O http://192.168.56.103:8000/web-share-sample.txt

The file downloads to the current directory.

Step 5: Stop the HTTP Server

On the primary system, stop the server by pressing ctrl+c.

Conclusion

This tutorial explained how to transfer files and directories between two Linux systems. Additionally, it outlined the prerequisites and conditions necessary for the transfer to occur.

Next, learn how to mount remote file systems on Linux and Windows.