I do have some text sequences that are replaced by the SCM (Perforce in my case).
I do want to configure BeyondCompare to consider these sequences as unimportant differe
You need to define a new grammar element (let's call it "SCM") and mark it as unimportant (see the tutorial here; choose "Basic" and make sure to check "Regular Expression").
The grammar element should be (if I interpret your examples correctly):
^.*\$(Id|DateTime|Author|Change):.*$
This will ignore any line that contains $Id:
, $DateTime:
etc.
If you only want to ignore lines that start with # $...
, use
^\s*#s*\$(Id|DateTime|Author|Change):.*$
And if you only want to ignore stuff between $
(and treat everything else as important), use
\$[^$\r\n]*\$
or
\$(Id|DateTime|Author|Change)[^$\r\n]*\$
depending on whether you care about those keywords or not.