I am trying to migrate from log4j2 to logback. I am trying to find equivalent syntax for filename and filepatterns in this case

log4j2.xml

<RollingFile name="myLOg" fileName="/log/${env1}-{{*myEnv|||@mydir@*}}-app.log"  .../>

When i use something like this I get an exception saying invalid Repition. I m not sure what the above code was intended to do.

1. How can i convert this fileName to a valid one in logback ? 

2. I do understand it will resolve ${env1} properly from environment variables. The "myENv" is being defined in a .properties file being loaded by the application. I have seens examples in logback.xml like

<RollingFile name="myLOg" fileName="/log/${env1}-:[myEnv]-app.log"  .../>

what does the :[myEnv] do here ? Would it resolve to a property set in a .properties file?

ALso not sure what the @ symbol means in the log4j, and if it has any equivalent here?

thanks for any pointers

Best Regards

Ani