Published on February 26, 2012 by Alexandru Juncu
Tagged: scp, nc, netcat, python

You are on a (Linux) box and you want to transfer some files on another system. What are some ways to do that?

The first and most obvious way is to copy them over ssh using the scp tool. You can copy to and from the server and you can use the recursive copy to transfer entire directories.

But what if you don’t have proper account access (you can’t reach accounts because of lack of passwords or keys, for example)? Here is a rather hackish solution: nc.

The netcat tool (the nc command) is found on most Linux systems. You can create TCP or UDP servers and clients with just one command. You can use the shell redirection operators to put files into a TCP stream and take the data out of the stream. Here is an example of a copy from a server to a client:

alexj@ixmint ~ $ md5sum
alexj@ixmint ~ $ cat|nc -l 12345

alexj@hathor /tmp $ nc ixmint.local 12345 >
alexj@hathor /tmp $ md5sum

You could transfer an entire directory (or several files) by first compressing the content.

alexj@ixmint ~ $ tar -czvf - some_folder | nc -l 12345

alexj@hathor /tmp $ nc ixmint.local 12345 | tar xzvf -

What other more user friendly ways are there? HTTP would be good at this, but configuring Apache with vhosts and aliases is kind of an overhead. What you can do, is start a HTTP server using Python in just one line

alexj@ixmint ~ $ python -m SimpleHTTPServer 1234
Serving HTTP on port 1234 ...

The current working directory where you ran the command will be the www root and any files in that directory will be published (as long as the process will have correct permissions to those files). You can then use a web browser (it can be Firefox or other GUI clients or a simple wget) to access the URL.

Credits to Alex Morega for tar | nc idea and Vlad Dogaru for python SimpleHTTPServer idea.

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