The wall command (short for write all) is used to send a message to all logged-in users on a Linux system. It is commonly used by system administrators to broadcast important information, such as planned maintenance or urgent announcements.
wall [options] [message]
If no message is provided as an argument, wall will read the message from standard input (stdin).
Some popular option flags include:
-n Do not display the header (username and terminal of the sender).
-t [seconds] Set a timeout for writing the message to each terminal.
- Broadcast a message to all users
wall "The system will shut down in 10 minutes. Please save your work."
- Broadcast a message from a text file
wall < message.txt
- Send a message without showing the sender header
wall -n "Maintenance completed successfully."
Here I showed you how to use the wall command in Linux. It is a simple but effective tool for system-wide communication, especially useful when you need to notify multiple logged-in users at once.
For more details: Wall (Unix) on Wikipedia