Configure SSH for multiple remote machines without the need for defining parameters every time

I usually connect to remote machines and giving ssh key location, hostname, and username etc.. every time is painful, isn't there a simple way to configure it?

Yes, there is.

1. Create a .ssh directory under home directory if it does not exist.

$ mkdir -p ~/.ssh

2. Open a file named config (create it if it does not exist)

$ vi ~/.ssh/config

3. Configure hosts in this file. Copy the following code and replace the values accordingly.

#Demo server configuration

Host demo      

HostName 12.14.134.123

User john

IdentityFile ~/.ssh/ssh_key

#Test server configuration

Host test      

HostName 12.14.134.124

User john

IdentityFile ~/.ssh/ssh_key

4. To connect to remote machine.

$ ssh demo

5. To copy a file from demo server to your machine

$ scp demo:~/file1.txt ~/Downlods/