Scp file transfer linux

10 SCP Commands to Transfer Files/Folders in Linux

Linux administrators should be familiar with the CLI environment. Since GUI mode in Linux servers is not common to be installed. SSH may be the most popular protocol to enable Linux administrators to manage the servers via remote secure way. Built-in with SSH command there is SCP command. SCP is used to copy file(s) between servers in a secure way.

10 Linux SCP Commands

Basic Syntax of SCP Command

The below command will read as “copy source_file_name” into “destination_folder” at “destination_host” using “username account”.

There are many parameters in the SCP command that you can use. Here are the parameters that may use on daily basis usage.

Provide the detailed information of the SCP process using the -v parameter

The basic SCP command without parameters will copy the files in the background. Users will see nothing unless the process is done or some error appears.

You can use the “-v” parameter to print debug information into the screen. It can help you debugging connection, authentication, and configuration problems.

Sample Output

Provide modification times, access times, and modes from original files

The “-p” parameter will help you with this. An estimated time and the connection speed will appear on the screen.

Sample Output

Make file transfer faster using -C parameter

One of the parameters that can faster your file transfer is the “-C” parameter. The “-C” parameter will compress your files on the go. The unique thing is the compression-only happens in the network. When the file has arrived at the destination server, it will be returning to the original size as before the compression happen.

Take a look at these commands. It is using a single file of 93 Mb.

Sample Output

Copying files without the “-C” parameter will result in 1661.3 seconds. You may compare the result to the command below which using the “-C” parameter.

Sample Output

As you can see, when you are using compression, the transfer process is done in 162.5 seconds. It is 10 times faster than not using the “-C” parameter. If you are copying a lot of files across the network, the “-C” parameter would help you to decrease the total time you need.

The thing that we should notice is that the compression method will not work on any files. When the source file is already compressed, you will not find any improvement there. Files such as .zip, .rar, pictures, and .iso files will not be affected by the “-C” parameter.

Change SCP Cipher to Encrypt Files

By default SCP using “AES-128” to encrypt files. If you want to change to another cipher to encrypt it, you can use the “-c” parameter. Take a look at this command.

The above command tells SCP to use the 3des algorithm to encrypt the file. Please be careful that this parameter using “-c” not “-C“.

Limiting Bandwidth Usage with SCP Command

Another parameter that may be useful is the “-l” parameter. The “-l” parameter will limit the bandwidth to use. It will be useful if you do an automation script to copy a lot of files, but you don’t want the bandwidth is drained by the SCP process.

The 400 value behind the “-l” parameter is mean that we limit the bandwidth for the SCP process to only 50 KB/sec. One thing to remember is that bandwidth is specified in Kilobits/sec (kbps). It is mean that 8 bits are equal to 1 byte.

While SCP counts in Kilobyte/sec (KB/s). So if you want to limit your bandwidth for SCP maximum of only 50 KB/s, you need to set it into 50 x 8 = 400.

Specify the Specific port to use with SCP

Usually, SCP is using port 22 as a default port. But for security reasons, you may change the port into another port. For example, we are using port 2249. Then the command should be like this.

Make sure that it uses capital “P” not “p” since “p” is already used for preserved times and modes.

Copy files inside directory recursively

Sometimes we need to copy the directory and all files/directories inside it. It will be better if we can do it in 1 command. SCP supports that scenario using the “-r” parameter.

When the copy process is done, at the destination server you will found a directory named “documents” with all its files. The folder “documents” is automatically created.

Disable progress meter and warning / diagnostic message

If you choose not to see progress meter and warning / diagnostic messages from SCP, you may disable it using the “-q” parameter. Here’s the example.

As you can see, after you enter the password, there is no information about the SCP process. After the process is complete, you will see a prompt again.

Copy files using SCP through Proxy

The proxy server is usually used in the office environment. Natively, SCP is not proxy configured. When your environment using a proxy, you have to “tell” SCP to communicate with the proxy.

Here’s the scenario. The proxy address is 10.0.96.6 and the proxy port is 8080. The proxy also implemented user authentication. First, you need to create the “

/.ssh/config” file. Second, you put this command inside it.

Then you need to create file “

/.ssh/proxyauth” which contains.

After that, you can do SCP transparently as usual.

Please notice that the corkscrew is might not be installed yet on your system. On my Linux Mint, I need to install it first, using the standard Linux Mint installation procedure.

For other yum-based systems, users can install corkscrew using the following yum command.

Another thing is that since the “

/.ssh/proxyauth” file contains your “username” and “password” in clear-text format, please make sure that the file can be accessed by you only.

Select different ssh_config file

For mobile users who often switch between the company networks and public networks, it will be suffering to always change settings in SCP. It is better if we can put a different ssh_config file to match our needs.

Here’s a sample scenario

Proxy is used in the company network but not in the public network and you regularly switch networks.

By default “ssh_config” file per user will be placed in “

/.ssh/config“. Creating a specific “ssh_config” file with proxy compatibility will make it easier to switch between networks.

When you are on the company network, you can use the “-F” parameter. When you are on a public network, you can skip the “-F” parameter.

That’s all about SCP. You can see man pages of SCP for more detail. Please feel free to leave comments and suggestions.

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12 scp Command Examples to Transfer Files on Linux

scp command — Secure copy

Scp (Secure Copy) is a command line tool to copy or transfer files across hosts. It uses the same kind of security mechanism like the ssh program.

Infact it uses an ssh connection in the background to perform the file transfer. scp refers both to the «protocol» that defines how secure copy should work and the «program» (command) which is installed as a part of OpenSSH suite of tools.

In this quick tutorial we shall look at a few examples the scp command and how it can be used to transfer files securely.

How to install scp

Scp is generally installed by default on most linux distros as a part of openssh packages. On ubuntu/debian for example, the openssh-client package provides the scp program.

Its the OpenSSH package that provides the ssh, scp, sftp programs along with many other tools. So we do not have to do anything extra in here, except to use and learn the program.

Using scp — basic syntax

The basic syntax of scp is very simple to memorize. It looks like this

Depending on the host, the file path should include the full host address, port number, username and password along with the directory path.

So if you are «sending» file from your local machine to a remote machine (uploading) the syntax would look like this

When copying file from remote host to local host (downloading), its looks just the reverse

That is pretty much about using scp for regular tasks. Apart from it, there are a couple of extra options and functions that scp supports. Lets take a quick overview of those.

And yes, by default scp will always overwrite files on the destination. If you need to avoid that, use a more powerful tool called rsync.

scp command examples

1. Verbose output

With verbose output, the scp program would output lots of information about what it does in the background. This is often useful when the program fails or is unable to complete the request. The verbose output would then indicate the exact point where the program ran into issues.

The output would be big and contain detailed information about how the connection is made, what configuration and identity files are being used and so on.

2. Transfer multiple files

Multiple files can be specified separated by a space like this

To copy multiple files from remote host to current local directory

3. Copy entire directory (recursively)

To copy an entire directory from one host to another use the r switch and specify the directory

4. Copy files across 2 remote hosts

Scp can copy files from 1 remote host to another remote host as well.

5. Speed up the transfer with compression

A super cool option to speed up the transfer to save time and bandwidth. All you need to do is use the C option to enable compression. The files are compressed on the fly and decompressed on the destination.

In the above example we moved the entire directory with compression enabled. The speed gain would depend on how much the files could be compressed.

6. Limit the bandwidth usage

If you do not want scp to take up the entire available bandwidth, then use the l option to limit the maximum speed in Kbit/s.

7. Connect to a different port number on remote host

If the remote server has ssh daemon running on a different port (default is 22), then you need to tell scp to use that particular port number using the ‘-P’ option.

8. Preserve file attributes

The ‘-p’ option (smallcase), would preserve modification times, access times, and modes from the original file.

9. Quiet mode

In quiet mode ( ‘-q’ option ), the scp output would get suppressed, and would disable the progress meter as well as warning and diagnostic messages.

10. Specify identity file

When using key based (passwordless) authentication, you would need to specify the identity file which contains the private key. This option is directly passed to the ssh command and works the same way.

11. Use a different ssh_config file

Use the ‘-F’ option to specify a different ssh_config file.

12. Use different cipher

Scp by default uses the AES cipher/encryption. Sometimes you might want to use a different cipher. Using a different cipher can speed up the transfer process. For example blowfish and arcfour are known to be faster than AES (but less secure).

In the above example we use the blowfish cipher along with compression. This can give significant speed boost depending on available bandwidth.

Summary

Although scp is very efficient at transferring file securely, it lacks necessary features of a file synchronisation tool. All it can do is copy paste all the mentioned files from one location to another.

A more powerful tool is Rsync which not only has all functions of scp but adds more features to intelligently synchronise files across 2 hosts. For example, it can check and upload only the modified files, ignore existing files and so on.

A Tech Enthusiast, Blogger, Linux Fan and a Software Developer. Writes about Computer hardware, Linux and Open Source software and coding in Python, Php and Javascript. He can be reached at [email protected] .

8 thoughts on “ 12 scp Command Examples to Transfer Files on Linux ”

Great information. i have aslo written for rsync.

hello, how i can transfer but NOT overwrite information

I am using SCP file transfer centos

I have this Script running in cronjob as following:

scp /opt/pcube/sm/server/bin/subscribers.csv [email protected] .1.1:/var/tmp

When I press enter will ask for password: [email protected] .1.1’s password: XXXX

After I put the password:

Subscribers.csv 100% 155KB 155.4KB/s 00:00 the transfer is done without problem

My questions: I want to run the script on hourly bases without asking me for the password (I want to save the password and the script will run without asking me ) is it possible

Thanks. My hosting provider (https://rosehosting.com) encouraged me to use WinSCP for uploading files on my server. They told me that scp is much secure than ftp. Your guide is very useful and I will add it to my bookmarks so I can use it when I need to upload something using the command line.

How about the rsync article then .

Read the man page? Once you have scp down then rsync is just more of the same with different switches.

How about resume upload and download?

I don’t know to resume with scp too. When I need to transfer a large amount of files I use rsync over ssh. With rsync, if transfer or link suffer interrupt, you can restart rsync to continue.

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