Password-less auto-login with SSH

There are two steps.

1. Creating the SSH key on the local machine

2. Transferring the public key to the remote host and appending it to ~/.ssh/authorized_keys (which requires access to the remote machine)

$ ssh-keygen -t rsa 
Generating public/private rsa key pair.  
Enter file in which to save the key (/home/username/.ssh/id_rsa):  
Created directory '/home/username/.ssh'.  
Enter passphrase (empty for no passphrase):  
Enter same passphrase again:  
Your identification has been saved in /home/username/.ssh/id_rsa.  
Your public key has been saved in /home/username/.ssh/  
The key fingerprint is:  
f7:17:c6:4d:c9:ee:17:00:af:0f:b3:27:a6:9c:0a:05 username@slynux-laptop 
The key'srandomart image is:  
+--[ RSA 2048]----+  
|           .     |  
|            o . .| 
|     E       o o.| 
|      ...oo |  
|       .S .+  +o.|  
|      .  . .=....|  
|     .+.o...|  
|      . . + o.  .| 
|       ..+       |  

The easiest way to upload is

ssh-copy-id USER@REMOTE_HOST

If ssh-copy-id is not available, do this instead:

    "cat >> ~/.ssh/authorized_keys" < ~/.ssh/

To test that it works:

$ ssh USER@REMOTE_HOST uname

More Linux Commands

Adding execute permission for yourself

$ chmod u+x <filename>

Change a files owner and group-owner

$ chown olga:olga <filename>

Recursively for all directories and files (as seen from current directory)

$ chown -R olga:olga *