msgcomm

msgcomm [-n] [-q msgqid] [-t msgtype] [message]

-q msgqid
    Specifies the message queue ID (msgqid). This is a required parameter.

-t msgtype
    Specifies the message type (msgtype). This is an integer value used to filter messages.

message
    The message to be sent to the message queue. If no message is provided, the command attempts to read a message from the queue.

-n
    Prevents `msgcomm` from appending a newline character to the message when sending.

The `msgcomm` command is used to send and receive messages between processes using System V message queues.
It is a versatile tool that allows for basic inter-process communication (IPC) without the complexities of sockets or pipes. It allows sending and receiving data through message queues by specifying the queue ID, message type, and the message itself.
It provides a simple interface for programs to exchange information and synchronize their activities.
It allows writing data to the given queue or reading data from that queue.
If message is not specified, the command reads from the queue.

The message queue ID must already exist before `msgcomm` can be used. Message queues are system resources and should be carefully managed to avoid resource exhaustion. Security concerns such as privilege escalation when accessing message queues should be considered when using this command.

msgcomm provides minimal error reporting. Errors typically result in a non-zero exit status. It is important to check the exit status to determine whether the command was successful. Check the system logs and/or use strace for more detailed debugging.

ipcs(1), ipcrm(1), msgget(2), msgsnd(2), msgrcv(2), msgctl(2)