Linux provides users with tools to communicate with each other. Some can send messages to a specified user; some can send a group of messages; some can even send content as an email to a user’s inbox list.

Send Message to a Specific User

Before we send information to a user, we first need to know which terminal the message receiver is at:

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who

When we know the terminal of the message receiver, we can send some messages to the terminal:

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write user pts/1    # Run this command first
Hi Mate,
This is a msg from root.
Root
# Press Ctrl + D at this line

When the message is sent, the receiving terminal should print out the content just sent out by the root terminal:

Disable or Enable Messaging Function

We can use the mesg command to turn on or off the ability to send and receive messages.

Here are two arguments for mesg command:

We can set root to not receive or send messages:

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mesg n

When a user attempts to send a message to root, the system displays that root has disabled the messaging feature:

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write root pts/0

Group Messaging Function

We can use the wall command to broadcast messages to all users:

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wall

When the message is broadcasted, the receiving terminals should print out the content just sent out by the root terminal:

Output the Message Without the Banner

With the -h option, the message sent does not display the sending host:

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wall -n

When the message is broadcasted, the receiving terminals should print out the content just sent out by the root terminal without the banner:

Send an Email to a User

We can send mail to users based on mail, but we first need to install the mailx package:

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yum mailx -y

We can try sending an email to root:

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mail -s 'Hi root' root
Hi Mate,
This is an email from user.
Talk soon.
User
.    # This is act as an terminate symbol

The root user’s terminal should prompt a message:

We can view the newly received mail through the mail command:

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mail

When we have finished checking the e-mail, we can terminate the program by pressing the Ctrl + D key combination.

References WRITE(1), MESG(1), WALL(1), GNU Mailutils

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