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

Description:
   This hook is triggered whenever an EXECed process produces output to
   standard error.

Parameters:
   $0    process number or name of the EXECed process
   $1-   a line of the process's output to stderr

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

See Also:
   exec(5); on(5) exec, exec_exit, exec_prompt