Secure Copy (SCP)

From Luke Jackson

Contents 1 Summary 2 Differences on Operating Systems 3 Examples 3.1 Uploading 3.2 Downloading 3.3 Escaping Spaces 4 Further

Summary

Secure Copy is the quickest, most effect way to transfer data from one machine to another. It's speeds surpass that of SFTP by far, but still are encyrpted with a rock solid algorithm. It may seem a little tricky at first, but it can prove to be quite useful, especially if you can utilize bash scripting.

Differences on Operating Systems

Secure Copy comes standard on all Linux based systems (including OS X) under the command scp.

While not native to Windows, there is a Windows program that acts the same called pscp, which is created by the same people who distribute putty [1].

To install on Windows, download and save pscp.exe to C:\WINDOWS\. This way you can type pscp in any folder and still have access to it. If you are using pscp, please remember throughout this guide to replace scp with pscp!

Some drawbacks to the windows version of pscp:

• Does not support files over 2GB. It doesn't tell you, either, it just corrupts the file.
• Does not transfer as quickly as scp.
• Does not support spaces of any type in file names (quotations won't save you this time!)

Examples

Uploading

To put a file in your home directory on the server:

scp local_file.txt user@server.com:

To send a file to a specific directory:

scp local_file.txt user@server.com:/directory/to/folder/you/want/it/to/go/

To put the file on the server in a subfolder of your home dir named "downloads", the command would be:

scp local_file.txt user@server.com:downloads/

Notice the difference between the last two. When going to a folder that does not reside within your home dir, you must start with the root directory and give a full path. When you are adding stuff to your home folder, you do NOT start with a root directory! (Root directory is the forward slash to the very left of the path.)

(The following tip does not work from pscp, ONLY scp): If your local username is the same as the remove username, you can omit your login name from the command. For instance, if your local login is jwatt and your remove login is jwatt, you can take this command:

scp local_file.mp3 jwatt@gtwy.net:music/

and simplify it, turning it into:

scp local_file.mp3 gtwy.net:music/

This doesn't work on Windows because local Windows users are different than linux users.

To upload a directory to a webserver, you use the recursive switch -r:

scp -r local_folder/ user@server.com:/path/to/wherever/

After uploading, the folder location will be:

/path/to/wherever/local_folder/

Downloading

To download the file "serials.txt" from your remote home dir to the local computer:

scp user@server.com:serials.txt .

To download the remote file "something" using it's full path to your local computer:

scp user@server.com:/path/to/file/something.txt .

Now the tricky part: using the recursive switch (-r) to download a whole folder to your local computer. The issue you may have is that you DO NOT place a trailing forward slash after the directory name. For instance, this command will NOT work (notice the bold forward slash):

scp -r user@server.com:/path/to/directory/ .

This will give you a message saying the server is trying to write to the parent directory. REMOVE the last foward slash on the path and try again. The next command is CORRECT:

scp -r user@server.com:/path/to/directory .

I have been using a period when talking about downloading so far. Reason: this brings the file into the directory you are currently in. If you wish to take the last command and download it to somewhere else, the command would be:

scp -r user@server.com:/path/to/directory /new/local/location/

Escaping Spaces

Below is an example of how to work with spaces in directory structure:

scp user@server.ext:'/home/samba/Service\ Deliver/System\ Admin/file\ name.sxw' .

Further

You can also use scp/pscp in bash scripting. See my Dedicated Bittorrent Server guide for examples.