in reply to Thoughts on designing a file format.

All good points ++

I read a paper once that explained very clearly why the two character line endings (CR, LF) in DOS was a mistake, I have no idea where it was but Wikipedia echoes the sentiment. Either way documenting it is OK but using the line endings appropriate for your OS is a better approach.

Two points I would add

Hence any data file parsing I do usually ends up beginning like this-

next if /^\s*#/; next if /^\s*$/;

Murray Barton
Do not seek to follow in the footsteps of the wise. Seek what they sought. -Basho