Hello Marcin
It is true that some debug commands show a lot of data. However, there are tools and methods that you can use to simplify you searching through the output. One of the most beneficial is to send the output you see to a local text file. This can be done using your terminal software’s capabilities (Putty and SecureCRT both have this feature, as do most terminal software packages). Once you have that you can then more easily search through using a text editor like Windows Notepad, but preferably a more advanced text editor such as Notepad2, or Sublime which have better search and text editing features that can help you.
If you are looking for a particular MAC address within the output, then you can easily find it and its associated debug output within such saved text.
Some additional helpful information for debugging best practices can be found here:
Although it is specific to voice applications, the principles are the same.
I hope this has been helpful!
Laz