Smart Cities - Transferring Files using Secure Copy

Introduction

• The fastest way to copy files between two computers is to use Secure Copy (scp)[1][2].
• This method is executed from the Terminal and hence eliminates the overhead of a GUI application.
• It is both fast and secure.
• Files can be transferred in both directions.

Prerequisites

• In this lesson it is assumed that Secure Shell (SSH) has been enabled on both computers.

Enabling SSH on a Raspberry Pi

• In the Terminal enter the command sudo raspi-config

• In the raspi-config menu select Interface Options

• Select SSH (Secure Shell) and then select Enable SSH

• SSH will now be enabled. There is no need to reboot the computer.
• Exit raspi-config

Copy File From Local Host to Remote Server

• In this example we will copy a file from a local host computer to a remote computer on the same network [3].
  • 192.168.1.105 Local computer IP address
  • 192.168.1.120 Remote computer IP address
  • On the Host computer create a new directory named test with the command mkdir test
  • Enter the directory using cd and create an empty file named file_to_send.txt with the command touch file_to_send.txt
• To send the file enter the command scp file_to_send.txt pi@192.168.1.120:/home/pi/
• You will be asked to enter the pi user password on the Remote computer

• The file will now appear on the Remote computer in the /home/pi directory

Copy Files From Remote to Local

• In this example we will copy a file from a remote computer to a local computer (the one issuing the commands) on the same network.
  • 192.168.1.105 Local computer IP address
  • 192.168.1.120 Remote computer IP address

• • A file named remote_file.txt has been created on the remote computer.
• To send the file from the remote computer to the local computer (user home directory) enter the command scp pi@192.168.1.120:/home/pi/remote_file.txt .
• The dot (.) at the end means to copy to file to the user home directory of the local computer.
• You will be asked to enter the password of the pi user on the Remote computer.

Copy Files From Remote to Local using Public and Private keys

• Secure Copy (scp) works the same way but with a few Options added to the instruction.
  • -P the Port may need to be specified
  • -i the path to the private key on the Local computer
  • IP address of the remote computer
  • path and file name for the file on the remote computer

• In this example the file on the remote computer is located at /home/pi/solar_python/data.db

• To copy the file from the remote computer enter the command scp -P 1099 -i /Users/edmond/.ssh/solar-pi pi@110.174.170.224:/home/pi/solar_python/data.db .
  • -P 1099 is the port
  • -i /Users/edmond/.ssh/solar-pi is the location of the Private key on the Local computer
  • pi@110.174.170.224 is the IP address of the Remote computer
  • :/home/pi/solar_python/data.db is the path to the file on the Remote computer
  • . (dot) indicates to copy the file to the current working directory on the Local computer. We could specify any path and also a new file name for the copied file.