wall:tldr:5015f

The command "wall --timeout ${seconds} ${file}" is used to send a message to all currently logged-in users on a Unix-like system.

Here's what each part of the command does:

• "wall" is the command itself. It stands for "write all" and is used to broadcast a message to all users.
• "--timeout ${seconds}" is an optional flag that specifies the amount of time (in seconds) the message should be displayed on the users' screens. After the specified time elapses, the message will automatically be removed from the screens. If this flag is not provided, the message will stay until the user manually removes it.
• "${file}" is an optional argument that specifies a file containing the message to be sent. Instead of typing the message directly in the command, you can provide a file containing the text. This is useful for sending large or complex messages.

In summary, the command "wall --timeout ${seconds} ${file}" sends a message to all logged-in users, with an optional timeout, and optionally reads the message from a file.