From http://web.presby.edu/support/Terminal/scp.html :

Downloading a file:

scp username@hostname:pathname/filename .

For example:

$ scp jtbell@web.presby.edu:/Library/WebServer/Documents/support/FireFTP/PopupMenu.jpg .

Don’t forget the space before the final “.”.

Uploading a file:

The general format for the command to upload to the server is:

scp filename username@hostname:pathname

For example, if I want to transfer the file PopupMenu.jpg in the folder /Users/jtbell/Sites/support/FireFTP/ on my computer, to the directory (folder) Library/WebServer/Documents/support/FireFTP/ on the server, I enter the following:

$ cd /Users/jtbell/Sites/support/FireFTP
$ scp PopupMenu.jpg jtbell@web.presby.edu:/Library/WebServer/Documents/support/FireFTP/
Password: (enter password here) 
PopupMenu.jpg                                 100%   83KB  82.7KB/s   00:00    

After I enter the command, it asks you for your login password on the server. (Exception: if this is your first time using scp, you may first get a warning about the authenticity of the server. See this page for more information.) If there is already a file named PopupMenu.jpg in that directory, it is replaced.

I could also combine the two commands by giving the complete path to the file on my computer:

$ scp /Users/jtbell/Sites/support/FireFTP/PopupMenu.jpg jtbell@web.presby.edu:/Library/WebServer/Documents/support/FireFTP/

but that’s a lot to type all at once! Besides, I often want to transfer more than one file, and it’s a nuisance to type the path over and over again.

You can also use the usual Unix-style wildcard characters in the filename. For example, to upload all the .jpg files in the current folder, I would use:

$ scp *.jpg jtbell@web.presby.edu:/Library/WebServer/Documents/support/FireFTP/

For our Windows friends, use WinSCP