Dummy variable is a virtual variable in the shape of $type:_dummy in a line pattern and will not be extracted as a parser variable.
Using a dummy variable is to skip a specific type of variable that you are not interested in, like a placeholder. For example:
▪$mstring:_dummy indicates skipping multiple lines of string.
▪$string:_dummy($_dummy) indicates to skip a string.
▪$int:_dummy indicates to skip an integer.
▪$float:_dummy indicates to skip a float.
Take EIGRP neighbor for example: if you want to parse its output interface, the previous string starting with “via” must be skipped.