_rc - UDM Built-in Variable
The _rc built-in variable holds the current UDM return code, a numeric value that indicates the highest return code received from processing all UDM commands up to that point.
The value of _rc is the return code that the UDM Manager returns when it exits.
As with the _halton variable, _rc can be set, via the set command, to any of the following integers or convenience values:
0 / none |
Success or no error. |
4 / warn |
Warning has been issued. |
8 / error |
Error has occurred. |
16 / fatal error |
Fatal error has occurred. |
For example: