Sending Messages (the MESSAGE command):
- Messages can be sent from a macro using the MESSAGE command.
  - Typical usage:
```
plot/id=plot1 ...
...
message send ID="PLOT1" NAME="OPENFILE" DATA="world.prm"
```
  - See the MESSAGE explain file for details.
- The messages sent or received by a command are listed in the explain file for that command.
  - Example:
```
nM> explain plot messages
```

X-Midas Users Take Note:
Be careful when porting macros from X-Midas to NeXtMidas since the parameters for `MESSAGE` differ slightly. In general it is best to use the `TAG=` in NeXtMidas.