How do I security copy file from one server to another under Unix like operating system using secret file transfer protocol (sftp)?
sftp is an interactive file transfer program, similar to ftp, which performs all operations over an encrypted ssh transport. The syntax is as follows to copy file from one server to another.
Step #1: Starting sftp
The command for starting sftp session is as follows:
The first time you connect to server, sftp command will report that “The authenticity of the host can’t be established.”. This is normal and expected behavior. This means that sftp doesn’t have server in its database of known hosts. Answer yes at the prompt to connect to the server. Next, it will ask for your account password. Enter your password, and sftp will log in and present you with the sftp prompt as follows:
Step #2: sftp commands
sftp commands are similar to the Unix / Linux shell commands that you use for navigating files. You will be working with two servers or computers. So sftp will give you local and remote version of each command. Usually, all local commands are prefixed by an “l”.
Common sftp commands
|cd dir||Change directory on the ftp server to dir.|
|lcd dir||Change directory on your machine to dir.|
|ls||List files in the current directory on the ftp server.|
|lls||List files in the current directory on your machine.|
|pwd||Print the current directory on the ftp server.|
|lpwd||Print the current directory on your machine.|
|get file||Download the file from the ftp server to current directory.|
|put file||Upload the file from your machine to the ftp server.|
|exit||Exit from the sftp program.|
How do I get (download) file?
The get command in sftp allows you to download files from the sftp server. The syntax is:
To download a file called data.tar.gz, enter:
sftp> get data.tar.gz
Fetching /home/vivek/data.tar.gz to data.tar.gz /home/vivek/data.tar.gz 100% 1960 1.9KB/s 00:01
How do I put (upload) file?
The syntax is as follows to upload a file called file from local machine to the ftp server:
In this example, upload a file called Screenshot.png, enter:
sftp> put Screenshot.png
Uploading Screenshot.png to /home/vivek/Screenshot.png Screenshot.png 100% 12KB 12.2KB/s 00:00
How do I sftp from one server A to another Unix based server B?
First login to server A using the ssh command:
$ ssh user@serverA
Next, sftp to serverB:
$ sftp user@serverB
Finally, upload or download file to serverB:
sftp> put foo sftp> ls sftp> get bar sftp> lls sftp> exit