Communication Commands Or Methods In Linux.

When we work on Linux Operation system, we have to communicate with other devices.
For this, there are some basic utilities below that we can use.

• SSH
• Ping
• FTP

These utilities help us to communicate with Networks, Other Linux systems, and remote users.
So, let us learn them one by one.
SSH:- SSH which stands for Secure Shell, It is used to connect to a remote computer securely. Compare to Telnet, SSH is secure wherein the client /server connection is authenticated using a digital certificate and passwords are encrypted. Hence it's widely used by system administrators to control remote Linux servers.
The syntax to log into a remote Linux machine using SSH is.
$ssh username@ip-address or hostname
I am using a raspberry pi Board.

Now I am going to connect my laptop to the pi Board through SSH.
I have the IP of Pi board 192.168.6.87. If you don't know the IP You can use Angryip Scanner.

Use $ssh pi@192.168.6.87 in the terminal.

After entering it ask you the password of the remote device.
Once the password matched you logged in the remote device.

Once you are logged in, you can execute any commands that you do in your terminal for the remote device.
For example, I am using ls,pwd and cd command.

After using the ls command in output we get the list of file in that location.
After using the pwd command in output we get the current directory location.

After using the cd command we enter in the directory.
Let's move to the next topic Ping.

Ping:-This utility is commonly used to check whether your connection to the server is healthy or not.This command is also used in -
Analyzing network and host connections, Tracking network performance and managing it, Testing hardware and software issues.
Command Syntax:-
ping <IP Address> OR ping <hostname>
$ping 192.168.6.87
$ping google.com OR $ping raspberrypi.local
For example, I am trying to check the raspberrypi Board is up or not. So what I will do is,
Ping the IP address of raspberrypi board through below command.
$ping 192.168.6.87

$ping raspberrypi.local

Here, A system has sent 64 bytes data packets to the IP Address (192.168.6.87) or the Hostname(raspberrypi.local). If even one of data packets does not return or is lost, it would suggest an error in the connection. Usually, internet connectivity is checked using this method.
You may Press Ctrl + c to exit from the ping loop.

Let's move to the next topic FTP.

FTP:- FTP is file transfer protocol. It's the most preferred protocol for data transfer amongst computers.
We can use FTP to :- Logging in and establishing a connection with a remote host, Upload and download files, Navigating through directories, Browsing contents of the directories.
The syntax to establish an FTP connection to a remote host is -
$ftp <hostname>
Once you enter this command, it will ask you for authentication via username and password.

Once a connection is established, and you are logged in, you may use the following commands to perform different actions.

Command	Function
dir	Display files in the current directory of a remote computer
cd "dirname"	change directory to "dirname" on a remote computer
put	file upload 'file' from local to remote computer
get	file Download 'file' from remote to local computer
quit	Logout

You can read this blog at http://technicaltotke.com/communication-commands-methods-linux/ as well.