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Using the wall command on Linux

  Linux terminal running on a laptop
Fatmawati Achmad Zaenuri / Shutterstock.com

Would you like to send a message to all registered users? The command wall from Linux is more powerful than e-mail and is automatically addressed to the logged in user. It sends a message to all users of a terminal on a system.

The command wall

What if you want to quickly send a message to the logged in user of your computer? E-mail does not meet the requirements. They do not know when the email is read. If you need someone who knows something, that's no problem. Also, you do not want to block the inboxes of logged-out users who do not need to see the message.

Without additional effort and without loss of time you will not know who is logged in and from where. Your system may be located in Aberdeen, Washington, but there may be remote users from Aberdeen, Scotland. So how can you target a message to the logged in users?

Linux and other Unix-like operating systems provide you with an easy way to do this. The command wall is like a haunting telegram. A message is sent to all terminal users and the message is placed directly under their nose. Users can not miss it and you know they have it. You do not have to choose to open an application to see if you're waiting for a message.

The transmission is as subtle as a pudding cake in the face.

Sending a message

The test computer sending the message This article was examined and installed with Fedora Linux, but the command wall behaves the same way in other distributions.

The only difference you might encounter is that you need to use some Linux distributions sudo over the option to send a message from a text file, while other distributions require you to sudo always with wall use. This is actually a difference between Linux distributions, no difference to how the wall command works.

To send a message to all users, enter wall a space Message you want to send. On Fedora Linux, you must use sudo .

  sudo wall main printer until further offline. 

  Wall command in a terminal window.

Your message will be sent to all users with a terminal window open.

The local users RIa and Tom receive the message, as well as the remote user Dick, who happens to be working on a computer running Ubuntu.

 Wall message to local user Ria in a terminal window

 Wall message to local user tom in a terminal window

 Wall message to a remote user in a terminal window

They all get you no longer have to wonder if they have seen the message.

Sending a message from a file

You can prepare the message in a text file and save it for sending. If you have a repetitive cycle of messages that need to be sent, you can create a library of ready-made messages so you do not have to re-enter them every time.

The message in the text file message.txt was displayed in the terminal window with the command cat to ensure that it is the message to be sent.

The message is then sent by passing the name of The text file for the command wall as a command line parameter:

  cat message.txt 
  sudo wall message.txt 

  wall- Command for a text file in a terminal window

The local users Ria and Tom (and all other users who are logged in with an open terminal window) and the remote user Dick are still receiving the message. Wall message to Tom in a terminal window ” width=”646″ height=”242″ src=”/pagespeed_static/1.JiBnMqyl6S.gif” onload=”pagespeed.lazyLoadImages.loadIfVisibleAndMaybeBeacon(this);” onerror=”this.onerror=null;pagespeed.lazyLoadImages.loadIfVisibleAndMaybeBeacon(this);”/>

 Wall message to Tom in a terminal window

 Wall message to Dick in a terminal window

Messaging Etiquette

Since the command wall forwards the message to all terminal users, it can be a harrowing experience to get one. The use of the command wall should be kept to a minimum and used only where there is a real need. Otherwise, it will quickly become very scratchy.

A wall message stamps everything that is on the user's terminal. It does not actually overwrite anything – it does not change the text it landed on – but it will cover it up. This can be alarming for a user who does not know this.

Imagine, one of our local users edited an important file in Vi exactly as the Wall message is sent.

 Editing a file in vi in ​​a terminal window

The message arrives directly in the middle of its file.

 Stamping a file in vi in ​​a terminal on the wall window

To restore the correct view of the file, the user only has to scroll through the file a bit.

 The edit file was restored in vi in ​​a terminal window ]

It's easy enough to put the ad in a state where work can continue and blood pressure drop, but too many interruptions of this kind will leave you with a very angry group of users.

As practical as is wall use it as moderate.

What about graphical desktop users?

The The command wall reaches all users who are logged in with the terminal open, but not all users who use a graphical desktop environment without an open terminal window.

If someone uses a graphical desktop and has a terminal window open, they'll see it in the terminal window – but that's it. Do not rely on wall reaching someone outside the terminal.

This is not a decent one, but you can not deny that it conveys the message – in a traditional terminal environment.

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