File:: Find pl6

I have a directory tree like
raw-files-base-dir/
└── YYYY
    └── MM
        └── DD

I want to recurse through each and do 3 things
1. replace spaces in directory names with underscore
2. concatenate all filenames with a matching pattern
	i.e
	concatenate all files which have 'string1' in filename into a new file in the top directory
	and
	concatenate all files which have 'string2' in filename into a new file in the top directory

This paste is with regards to question I asked in IRC #perl6.