Unix - Communication

When you work in a distributed environment then you need to communicate with remote users and you also need to access remote Unix machines.

There are several Unix utilities which are especially useful for users computing in a networked, distributed environment. This tutorial lists few of them:

The ping Utility:

The ping command sends an echo request to a host available on the network. Using this command you can check if your remote host is responding well or not.

The ping command is useful for the following:

• Tracking and isolating hardware and software problems.
• Determining the status of the network and various foreign hosts.
• Testing, measuring, and managing networks.

Syntax:

Following is the simple syntax to use ping command:


Above command would start printing a response after every second. To come out of the command you can terminate it by pressing CNTRL + C keys.

Example:

Following is the example to check the availability of a host available on the network:


If a host does not exist then it would behave something like this:


The ftp Utility:

Here ftp stands for File Transfer Protocol. This utility helps you to upload and download your file from one computer to another computer.

The ftp utility has its own set of UNIX like commands which allow you to perform tasks such as:

• Connect and login to a remote host.
• Navigate directories.
• List directory contents
• Put and get files
• Transfer files as ascii, ebcdic or binary

Syntax:

Following is the simple syntax to use ping command:


Above command would prompt you for login ID and password. Once you are authenticated, you would have access on the home directory of the login account and you would be able to perform various commands.

Few of the useful commands are listed below:

Command	Description
put filename	Upload filename from local machine to remote machine.
get filename	Download filename from remote machine to local machine.
mput file list	Upload more than one files from local machine to remove machine.
mget file list	Download more than one files from remote machine to local machine.
prompt off	Turns prompt off, by default you would be prompted to upload or download movies using mput or mget commands.
prompt on	Turns prompt on.
Dir	List all the files available in the current directory of remote machine.
cd dirname	Change directory to dirname on remote machine.
lcd dirname	Change directory to dirname on local machine.
Quit	Logout from the current login.

It should be noted that all the files would be downloaded or uploaded to or from current directories. If you want to upload your files in a particular directory then first you change to that directory and then upload required files.

Example:

Following is the example to show few commands:


The telnet Utility:

Many times you would be in need to connect to a remote Unix machine and work on that machine remotely. Telnet is a utility that allows a computer user at one site to make a connection, login and then conduct work on a computer at another site.

Once you are login using telnet, you can perform all the activities on your remotely connect machine. Here is example telnet session:


The finger Utility:

The finger command displays information about users on a given host. The host can be either local or remote.
Finger may be disabled on other systems for security reasons.
Following are the simple syntax to use finger command:
Check all the logged in users on local machine as follows:

$ finger
Login	Name	Tty	Idle	Login	Time	Office
amrood		pts/0		Jun 25	08:03	(62.61.164.115)

Get information about a specific user available on local machine:


Check all the logged in users on remote machine as follows:

$ finger @avtar.com
Login	Name	Tty	Idle	Login	Time	Office
amrood		pts/0		Jun 25	08:03	(62.61.164.115)

Get information about a specific user available on remote machine:

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