Ignoring lines with #

I have been looking all over the internet for what I thought would be a simple answer to a question about Root. How do you get Root to ignore all lines that begin with the # symbol?

According to the description of the TTree::ReadFile: [quote]Lines in the input file starting with “#” are ignored. Leading whitespace
for each column data is skipped. Empty lines are skipped[/quote]

[quote] How do you get Root to ignore all lines that begin with the # symbol?[/quote]In which context?