Symmetric commands: prepipe

[Poshi]

It feels weird to me that we have a --prepipe[x] flag but not a --postpipe[x] one. I know that you always can redirect output to the command of your choice though a pipe, but the same could be said about the input.
I can see the need of a --prepipe[x] command when we have more than a single input file, and usually many input files end up being a single output stream; but there's a case you are not covering (and is explicitly not supported according the documentation): in-place modification of files not compressed/coded in a standard way.

Let's say I'm using a hand-made compressor suited to my data that can reduce the size more than the standard compressors. Let's call it reducer. The tool to recover that data is called expander.
How would you perform an in-place modification of more than one of those files?

mlr --csv -I --prepipe expander --mfrom data1.csv.reduced data2.csv.reduced -- cut -f field1

With a --postpipe[x] command, that would be possible.

[johnkerl]

@Poshi you're right -- I've always thought we don't need post-pipe since we have the Unix pipe for output. But you're quite right -- -I is the right place for this. :)