In this tutorial, we'll explain how to use the SFTP command in Linux.
The sftp (Secure File Transfer Protocol) command in Linux provides a secure and straightforward method for transferring files between a local machine and a remote server over an SSH (Secure Shell) connection. Unlike FTP, SFTP encrypts the data in transit, making it a more secure choice for file transfers. This tutorial will guide you through basic and advanced usage of the sftp command, ensuring you can leverage its full capabilities for secure file management.
Understanding SFTP
SFTP operates as an extension of SSH. It uses the same secure channel to transfer files, ensuring the data, authentication credentials, and commands are encrypted. This makes it an ideal choice for transferring sensitive data.
Prerequisites
Before you begin using the sftp command, ensure the following:
- A KVM VPS or dedicated server with any Linux distro installed.
- SSH Access: You must have SSH access to the remote system.
- SFTP Client: The sftp utility is typically pre-installed on most Linux distributions. You can verify its presence by running:
sftp -v
If not installed, you can install the OpenSSH client package:
sudo apt update && sudo apt install openssh-client # For Ubuntu/Debian
sudo yum install openssh-clients # For CentOS/RHEL
Credentials: You need the username and password or an SSH key for authentication.
How to Use the SFTP Command in Linux
Establishing an SFTP Connection
To initiate an SFTP session, use the following syntax:
sftp username@remote_host
Replace username with your remote system’s username and remote_host with its IP address or domain name. For example:
sftp user@example.com
Once connected, you will be prompted to enter the password. If authentication succeeds, you will enter the sftp> interactive prompt.
Basic SFTP Commands
Here are some essential SFTP commands for everyday use:
1. Navigating Directories
Change Directory on Remote System:
cd /path/to/remote/directory
Change Directory on Local System:
lcd /path/to/local/directory
List Directory Contents:
ls # Remote directory
lls # Local directory
2. Transferring Files
Download a File:
get remote_file_path
Example:
get /remote/path/file.txt
Download Multiple Files:
mget file1 file2 file3
Upload a File:
put local_file_path
Example:
put /local/path/file.txt
Upload Multiple Files:
mput file1 file2 file3
3. Working with Files
Rename a File:
rename old_name new_name
Remove a File:
rm file_name
Create a Directory:
mkdir directory_name
Remove a Directory:
rmdir directory_name
4. Checking File Transfers
Check File Details:
stat file_name
Verify the Current Working Directory:
pwd # Remote working directory
lpwd # Local working directory
Advanced SFTP Usage
1. Using SSH Key Authentication
For enhanced security, use SSH keys instead of passwords:
Generate an SSH Key Pair:
ssh-keygen -t rsa -b 4096 -f ~/.ssh/id_rsa
Copy the Public Key to the Remote Server:
ssh-copy-id username@remote_host
Connect Using SFTP:
sftp username@remote_host
2. Batch File Transfers
Automate file transfers using a batch file:
Create a Batch File:
echo -e "put file1.txt\nget file2.txt" > batch.txt
Run SFTP with the Batch File:
sftp -b batch.txt username@remote_host
3. Resume Interrupted Transfers
Use the reget and reput commands to resume incomplete downloads or uploads:
Resume Download:
reget file_name
Resume Upload:
reput file_name
4. File Permissions
Modify file permissions directly within the SFTP session:
chmod 644 file_name
Exiting an SFTP Session
To exit the SFTP session, type:
exit
or
bye
Troubleshooting Common Issues
1. Connection Refused
Ensure the SSH service is running on the remote server:
sudo systemctl start sshd
2. Permission Denied
Verify your username, password, or SSH key permissions.
3. Timeout Issues
Increase the SSH timeout settings by editing the SSH configuration file on the server (/etc/ssh/sshd_config) and setting:
ClientAliveInterval 120
ClientAliveCountMax 720
Conclusion
The sftp command is a powerful and secure method for transferring files in Linux environments. By mastering both its basic and advanced features, you can efficiently manage file transfers between systems while maintaining robust security. Incorporate these practices into your workflow to optimize data handling in various scenarios.
