Output formatted file to console

[csala]

Context

Sometimes it would be desirable to run mdformat to obtain the formatted markdown string without modifying the original source file.

For reference, other code formatting tools like black or isort offer this option in one way or another:

• black can be passed input via stdin and then outputs to stdout
• isort has a -d/--debug option which outputs to stdout

Proposal

Add a way to format a file and dump the formatted contents to stdout without touching the file.

I see several ways of achieving this:

1. Add some cli option to dump to console, like the -d/--debug option from isort
2. Add piping capabilities allowing - as input filename and then forcing output to stdout, like black does.
3. Add a -o/--output <filename> option to write to a different output file, potentially allowing - to indicate that outputs need to go to stdout

My preferred option here would be number 3, or a combination of 2 and 3, since this is the one that provides more flexibility.

[csala]

Forget this. I did not realize that point 2. above is already supported