Clog is a filter, which means it reads standard input, and writes that input to standard output. Here is an example of a filter that does nothing:
$ echo 'Hello Clog' | clog Hello Clog $
The input passed through Clog unchanged. This is because the input matched no default rules.
When you define rules in your ~/.clogrc
file, those rules are
matched against the input, and if a rule matches, the action defined by the
rule is performed.
When no section
is ѕpecified, as in the example above, the
'default
' section is used. When a section is ѕpecified, then
the named section is used. You can specify multiple sections if you wish to
combined rule sets.
The rules are applied to the input, in the order in which they are defined
in the ~/.clogrc
file. The first rule is run first, and so on.
This can mean that some rules are eclipsed by others, and you can modify
the behavior by reordering the rules.