Is there a variable holding the header line fileds?

[dclong]

i.e., column names? I want to select columns by name.

[alecthomas]

Not built-in, no, but that's an interesting idea. You're thinking of input where the first row is the column headers, like so?

count name
12 bob
34 fred

[alecthomas]

Implemented in v0.6.4 (fa5a596).