File transfer between Linux machines - scp

To copy a file from another machine:

# scp username@123.123.123.123:/get/this/file   /put/it/here

to copy a directory
# scp -r username@123.123.123.123:/get/this/file   /put/it/here

-r

Recursive, so it copies the contents of the source-file (directory in this case) recursively