Introduction to Ethereal (v.0.9.9), The Open Source Network-Protocol Analyzer

25
Ethereal
...Extracting data: display filters...
Ethereal display filter syntax, basic expression structure:
[!] E [rel-op val] [log-ops E [rel-op val]]...
where an element E is:
protocol[.field_1[.field_2]][substr]
the relational operators rel-op are:
== != > < >= <=
or
eq ne gt lt ge le
and the logical operators log-op are:
and or not xor
or
&& || ! ^^