Request for a mechanism to accept more target files than the platform line length will allow

[mkillianey]

Is your feature request related to a problem? Please describe.

When using black to format long lists of files, one must use a tool like xargs to avoid triggering the platform's maximum command-line length. For example, if I want to clean up the modified files in my workspace, I can't write this:

black $(git status --porcelain | cut -c3- | grep -e '*.py$')

Because the command-line would overflow. Instead, I have to write it this way, triggering black multiple times:

$(git status --porcelain | cut -c3- | grep -e '*.py$') | xargs black

(Yes, yes, I know that's not properly escaping the filenames...the point here is just that black is triggered multiple times, rather than once.)

Describe the solution you'd like

I would love some syntax to pass more files to black than will fit on my platform's command-line, perhaps similar to the way git add works, in that if this is in danger of overflowing:

git add -- $(command that generates many files)

It can be replaced by a single invocation:

$(command that generates many files) | git add --pathspecs-from-file=-

Describe alternatives you've considered

Using xargs to invoke black multiple times.