Comment lines may appear anywhere in the configuration file. A comment
is introduced with an exclamation point,
!, in column one.
Liberal use of comments to explain what is going on is encouraged.
It is important to distinguish between blank lines and comment lines. Blank lines play an important role in delimiting sections of the configuration file. Comment lines are ignored by the configuration file reading routines --- they are essentially "not there" as far as the routines are concerned and do not count as blank lines.