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FTP , or File Transfer Protocol, is a popular, unencrypted method of transferring files between two remote systems. As of 2022, it has been deprecated by most modern software due to its lack of security, and is mostly only used for legacy applications.

SFTP is Secure File Transfer Protocol, a separate protocol built into SSH that implements FTP commands over a secure connection. Generally, it can be used directly in any environment where an FTP server is still required.

In almost all cases, SFTP is more reliable than FTP due to its underlying security features and ability to piggyback on SSH connections. FTP is an insecure protocol that should only be used in limited circumstances or on networks you trust.

Although SFTP is integrated into many graphical tools, we will demonstrate how to use it through its interactive command line interface.

How to connect to SFTP

By default, SFTP uses the SSH protocol to authenticate and establish a secure connection. Therefore, you can use the same authentication methods as SSH.

Although we can use passwords for authentication by default, we recommend that you create SSH keys and transfer your public key to any system you need to access. This is more secure and can save time in the long run. For more information about setting up SSH keys, please refer to our How to Create Git SSH Keys.

Although we can use passwords for authentication by default, we recommend that you create SSH keys and transfer your public key to any system you need access to. This is much more secure and will save time in the long run.

If you can connect to your computer using SSH, you have completed all the necessary requirements to manage files using SFTP. Test SSH access using the following command:

$ ssh username@your_server_ip_or_remote_hostname

If you can connect, you can exit by entering the following command:

$ exit

Now we can establish an SFTP session by using the following command:

$ sftp username@your_server_ip_or_remote_hostname

This will allow us to connect to the remote system and the terminal prompt will change to the SFTP prompt.

sftp> 

If you are using a custom SSH port (not the default port 22), you can open an SFTP session as follows:

$ sftp -oPort=custom_port username@your_server_ip_or_remote_hostname

This will connect to the remote system via the port we specified.

Getting help with SFTP

The first and most useful command to learn is the help command. We can use this command to see how other SFTP commands are used.

sftp> help

or

sftp> ?

This will display a list of available commands:

Available commands:
bye                                Quit sftp
cd path                            Change remote directory to 'path'
chgrp grp path                     Change group of file 'path' to 'grp'
chmod mode path                    Change permissions of file 'path' to 'mode'
chown own path                     Change owner of file 'path' to 'own'
df [-hi] [path]                    Display statistics for current directory or
                                   filesystem containing 'path'
exit                               Quit sftp
get [-Ppr] remote [local]          Download file
help                               Display this help text
lcd path                           Change local directory to 'path'
. . .

We will introduce some commands in three parts.

Browsing the file system using SFTP

We can browse the file hierarchy of a remote system using a number of commands that function similarly to their shell counterparts.

First, let's orient ourselves by finding out which directory we are currently in on the remote system. Just like in a typical shell session, we can get the current directory with the following command:

sftp> pwd

The output is as follows

Remote working directory: /home/demouser

We can view the contents of the remote system's current directory with another familiar command:

sftp> ls

The output is as follows

Summary.txt     info.html       temp.txt        testDirectory

Note that the commands available in the SFTP interface are not fully functional as those in shell syntax and are not as feature-rich. However, they do implement some of the more important options, such as adding -la to ls to see more file metadata and permissions:

sftp> ls -la

The output is as follows

drwxr-xr-x    5 demouser   demouser       4096 Aug 13 15:11 .
drwxr-xr-x    3 root     root         4096 Aug 13 15:02 ..
-rw-------    1 demouser   demouser          5 Aug 13 15:04 .bash_history
-rw-r--r--    1 demouser   demouser        220 Aug 13 15:02 .bash_logout
-rw-r--r--    1 demouser   demouser       3486 Aug 13 15:02 .bashrc
drwx------    2 demouser   demouser       4096 Aug 13 15:04 .cache
-rw-r--r--    1 demouser   demouser        675 Aug 13 15:02 .profile

To move into another directory, we can use the following command:

sftp> cd testDirectory

lWe can now traverse the remote file system, but what if we need to access the local file system? We can direct the command to the local file system by prefixing it with a .

All the commands discussed so far have local equivalents. We can print the local working directory:

sftp> lpwd

The output is as follows

Local working directory: /Users/demouser

We can list the contents of the current directory on our local machine:

sftp> lls

The output is as follows

Desktop         local.txt       test.html
Documents       analysis.rtf        zebra.html

We can also change the directory we want to interact with on our local system:

sftp> lcd Desktop

In the next article we will introduce how to transfer files with remote servers using SFTP.