How to debug a batch job in D365 F&O

2) Select the batch.exe process and make sure show processes for all users is selected. 

Note : Batch Service has name batch.exe and its location is (C:\CustomerServiceUnit\DOBind\Packages\Cloud\AosWebApplication\
AosWebApplication.csx\roles\AosWeb\approot\bin ) –at least on locally deployed machines

After attaching the process  symbols will be loaded. When you will execute your batch job at that time you will be able to debug X++ code.