Add support for pipeline

[liruqi]

:-)

[physacco]

It's difficult to support pipeline for such cases because pipes are unseekable.
However, you can use it in this way:

$ producer > output
$ reverse output output.rev

[liruqi]

How about reverse with separater like line break "\n".
reverse each line

[physacco]

Just reversing each line is not enough, the lines must be reversed too, e.g. the 1st line will become the last line.
Anyway, you have to cache the whole file (reversed or not) in memory, or write it to a temporary file.