Sometimes your files have some some trivial part that you want to ignore when using Beyond Compare. There are several ways to do this.
For this example we will look at a pair of files in C language:
This way is crude but easy.
From the menu:
2. Then choose Category->Lines. Set that window similar to mine below. Then, you must go and UNcheck the box that calls that rule important:
If you want BC to evaluate all of the files in a Folder Compare session using this rule:
3. You can choose Session->SessionSettings->Importance and select AlsoUpdateSessionDefaults
The most computer-scienceish way to ignore things is with a mask or a regular expression. The mask is an asterisk wildcard combined with the string of the thing you are ignoring.