Question: How to use 'poor man's dfs'?

[dakusui]

In README, it is said that we can use bashreduce as a poorman's dfs by doing

br -r "cat > /tmp/myfile" < input

I think I can see a file 'input' will be distributed among the hosts with the file name /tmp/myfile.
But how can we read the file?

br -r "cat /tmp/myfile"

would give us a broken file since those distributed chunks do not have information about in what order the original file was written.
Or it is assumed that input is a file whose lines have numbers in order?