You can securely copy files or directories between remote hosts and local machine. The scp command transfer data using SSH, so it needs a password or passphrase for authentication.

To transfer files to an EC2 instance without using a password, you can use SSH key pairs for authentication. Here's a concise step-by-step guide:

Generate an SSH key pair on your local machine (if you haven't already):

ssh-keygen -t rsa -b 4096

Create an EC2 instance and specify the public key when launching the instance. This can be done either during the EC2 instance creation process or by modifying the instance's key pair later.

Retrieve the public DNS name or IP address of your EC2 instance.

From your local machine, use the scp command to securely copy files to the EC2 instance, specifying the private key associated with your SSH key pair:
scp -i /path/to/private_key.pem /path/to/local_file ec2-user@<EC2_INSTANCE_IP_OR_DNS>:/path/on/ec2/instance

Replace /path/to/private_key.pem with the path to your private key file, <EC2_INSTANCE_IP_OR_DNS> with the actual IP address or DNS name of your EC2 instance, /path/to/local_file with the path to the file you want to transfer, and /path/on/ec2/instance with the desired path on the EC2 instance.

By following these steps, you can securely copy files to an EC2 instance without the need for a password.