======Synopsis:======
[[on]] [<modes>]exec [<serial#>] [-|^]<match> { <action> }

======Description:======
This hook is triggered whenever an [[exec command|EXEC]]ed process generates output to
standard output.

======Parameters:======
|$0    |the exec name or refnum that triggered the hook. |
|$1-   | a line of the process's stdout |

======Default behavior:======
If you do not suppress this event, the client will format the message
and display it to your screen **UNLESS** you are redirecting the output
of that [[exec]] to somewhere else.

======Examples:======
To distinguish process output from other window output:
   on ^exec "*" {
      echo [$0] $1-
   }