`pickaxe`::
A constant string (can and typically does contain newlines to
look for a block of text, not just a single line) to filter out
the filepairs that do not change the number of strings contained
`pickaxe`::
A constant string (can and typically does contain newlines to
look for a block of text, not just a single line) to filter out
the filepairs that do not change the number of strings contained