How to use the command 'msg' (with examples)

The ‘msg’ command in Windows is a powerful tool used to send messages to users or sessions on a network or a local machine. This command is particularly useful for system administrators who need to notify users about system events, maintenance times, or to simply send alerts. The messages can be targeted to specific users or sessions, and even to all users on a server, offering significant flexibility in how information is communicated.

Use case 1: Send a message to a specified user or session

Code:

msg username|session_name|session_id message

Motivation:

In a multi-user environment, such as a shared server or a network of computers, administrators often need to communicate with individual users directly. Whether it’s to inform a user about private data cleanse cycles, ask them to log off for maintenance, or provide instructions on software updates, sending targeted messages ensures that specific individuals receive the information pertinent to them without disturbing others.

Explanation:

• msg: The command itself, used to initiate a message being sent.
• username|session_name|session_id: Specifies the recipient of the message. It can be a username directly, a session name, or an ID, giving flexibility depending on what reference system administrators prefer.
• message: The content of the message to be sent, providing the actual information or alert you wish to communicate.

Example output:

Message from SERVER01 to ADMIN01 on 12/23/2023 15:24

Please save your work and log off in the next 10 minutes for maintenance.

Use case 2: Send a message from stdin

Code:

echo "message" | msg username|session_name|session_id

Motivation:

Piping input from stdin to the ‘msg’ command is ideal in scripting environments or when building automation around system messages. For instance, a script can generate dynamic and context-sensitive messages on the fly, such as alerting a user when their resource usage exceeds a certain threshold, all without hardcoding the message directly into the msg command.

Explanation:

• echo "message": A command to pass a message string from standard input. This allows dynamic message content generation.
• |: A pipe operator, passing the output of echo directly into the msg command.
• msg username|session_name|session_id: The same parameters as in the above case, used to target the message correctly.

Example output:

Message from SERVER02 to JDOE on 12/23/2023 15:40

Resource usage has exceeded 80% – consider offloading tasks.

Use case 3: Send a message to a specific server

Code:

msg /server:server_name username|session_name|session_id

Motivation:

When working in large or complex network environments, administrators might need to send messages to users on specific servers. This is particularly useful for coordinated maintenance on particular machines or when an issue arises with a particular server and attention needs to be drawn immediately to the users connected to it.

Explanation:

• /server:server_name: Specifies a remote server where the message should be sent. Useful for administrative tasks involving remote systems.
• username|session_name|session_id: As with previous example, directs the message to the needed recipient.
• msg: The command initiates the messaging process.

Example output:

Message from IT-DEPT to USER100 on 12/23/2023 15:55

Please assist with diagnostics on SERVER03. Your session is identified for review.

Use case 4: Send a message to all users of the current machine

Code:

msg *

Motivation:

Sometimes a general announcement is necessary for all users connected to a system. This command is particularly powerful in sending broadcast messages to inform or alert every connected user simultaneously about actions affecting the entire system, such as imminent power shutdowns or urgent security notices.

Explanation:

• msg: The command to send messages.
• *: A wildcard character used to signify all users, allowing the message reach everyone currently logged into the system.

Example output:

Message from ADMIN to ALL USERS on 12/23/2023 16:10

Critical security update in progress – system restart at 16:30.

Use case 5: Set a delay in seconds for a message

Code:

msg /time:10

Motivation:

When sending messages, sometimes you might want to provide users with a specific time frame in which they can see the message before it disappears, especially if it’s being displayed on terminals or command prompts. The delay provides a controlled visibility period which is useful when timing is crucial for user awareness, such as logging off warnings or service availability announcements.

Explanation:

• msg: The command for sending messages.
• /time:10: Sets a 10-second delay after the message is displayed, ensuring users have a definite period to read the message before it automatically clears.

Example output:

Message from OPS to SESSION_5 on 12/23/2023 16:20

Please be aware that system access will be restricted in 15 mins – plan accordingly.
(This message will self-clear in 10 seconds)

Conclusion:

The ‘msg’ command provides an essential suite of communication tools for administrators, boosting efficiency in system management through timely, targeted, and flexible user notifications. Understanding these use cases can help in optimizing system operations and improving collaboration within multi-user environments.