Linux-Basics-Complete-Course-With-Notes-Slides

SSH and SCP

In this lecture we will learn about SSH and SCP commands.
SSH is used to login to the remote computer.
SCP is used to copy of files/directories within the file system also can copy data to remote computer.

#### SSH

To login to the remote server use ssh command with hostname or IP address.
```
ssh <hostname OR IP Address>
```
To login to the remote server with specific username and password.
```
ssh <user>@<hostname OR IP Address>
```
-l attribute can also be used as
```
ssh –l <user> <hostname OR IP Address>
```

#### Password-Less Authentication

Passwordless authentication can be setup via key-pair authentication in order to login to the remote server with password.

Public and Private key are stored at below location.

Public Key: /home/bob/.ssh/id_rsa.pub

Private Key: /home/bob/.ssh/id_rsa

To generate a keypair on the Client run this command
```
bob@caleston-lp10 ~]$ ssh-keygen –t rsa
```
To copy the Public key from the client to the remote server
```
bob@caleston-lp10 ~]$ ssh-copy-id bob@devapp01
```
Now bob can login to remote server without password
```
[bob@caleston-lp10 ~]$ ssh devapp01
```

Public Key is copied to the remote server at :

[bob@caleston-lp10 ~]$ cat /home/bob/.ssh/authorized_keys

auth

#### SCP

To copy a compresses file to a remote server

bob@caleston-lp10 ~]$ scp /home/bob/bob-code.tar.gz devapp01:/home/bob

To copy a directory to a remote server

[bob@caleston-lp10 ~]$ scp –pr /home/bob/media/ devapp01:/home/bob

scp