+#### `--diff`
+
+Passing `--diff` will make _Black_ print out diffs that indicate what changes _Black_
+would've made. They are printed to stdout so capturing them is simple.
+
+If you'd like colored diffs, you can enable them with `--color`.
+
+```console
+$ black test.py --diff
+--- test.py 2021-03-08 22:23:40.848954+00:00
++++ test.py 2021-03-08 22:23:47.126319+00:00
+@@ -1 +1 @@
+-print ( 'hello, world' )
++print("hello, world")
+would reformat test.py
+All done! ✨ 🍰 ✨
+1 file would be reformatted.
+```
+
+#### `--color` / `--no-color`
+
+Show (or do not show) colored diff. Only applies when `--diff` is given.
+
+#### `--fast` / `--safe`
+
+By default, _Black_ performs [an AST safety check](labels/ast-changes) after formatting
+your code. The `--fast` flag turns off this check and the `--safe` flag explicitly
+enables it.
+
+#### `--required-version`
+
+Require a specific version of _Black_ to be running. This is useful for ensuring that
+all contributors to your project are using the same version, because different versions
+of _Black_ may format code a little differently. This option can be set in a
+configuration file for consistent results across environments.
+
+```console
+$ black --version
+black, 23.3.0 (compiled: yes)
+$ black --required-version 23.3.0 -c "format = 'this'"
+format = "this"
+$ black --required-version 31.5b2 -c "still = 'beta?!'"
+Oh no! 💥 💔 💥 The required version does not match the running version!
+```
+
+You can also pass just the major version:
+
+```console
+$ black --required-version 22 -c "format = 'this'"
+format = "this"
+$ black --required-version 31 -c "still = 'beta?!'"
+Oh no! 💥 💔 💥 The required version does not match the running version!
+```
+
+Because of our [stability policy](../the_black_code_style/index.md), this will guarantee
+stable formatting, but still allow you to take advantage of improvements that do not
+affect formatting.
+
+#### `--include`
+
+A regular expression that matches files and directories that should be included on
+recursive searches. An empty value means all files are included regardless of the name.
+Use forward slashes for directories on all platforms (Windows, too). Exclusions are
+calculated first, inclusions later.
+
+#### `--exclude`
+
+A regular expression that matches files and directories that should be excluded on
+recursive searches. An empty value means no paths are excluded. Use forward slashes for
+directories on all platforms (Windows, too). Exclusions are calculated first, inclusions
+later.
+
+#### `--extend-exclude`
+
+Like `--exclude`, but adds additional files and directories on top of the excluded ones.
+Useful if you simply want to add to the default.
+
+#### `--force-exclude`
+
+Like `--exclude`, but files and directories matching this regex will be excluded even
+when they are passed explicitly as arguments. This is useful when invoking _Black_
+programmatically on changed files, such as in a pre-commit hook or editor plugin.
+
+#### `--stdin-filename`
+
+The name of the file when passing it through stdin. Useful to make sure Black will
+respect the `--force-exclude` option on some editors that rely on using stdin.
+
+#### `-W`, `--workers`
+
+When _Black_ formats multiple files, it may use a process pool to speed up formatting.
+This option controls the number of parallel workers. This can also be specified via the
+`BLACK_NUM_WORKERS` environment variable.
+
+#### `-q`, `--quiet`
+
+Passing `-q` / `--quiet` will cause _Black_ to stop emitting all non-critical output.
+Error messages will still be emitted (which can silenced by `2>/dev/null`).
+
+```console
+$ black src/ -q
+error: cannot format src/black_primer/cli.py: Cannot parse: 5:6: mport asyncio
+```
+
+#### `-v`, `--verbose`
+
+Passing `-v` / `--verbose` will cause _Black_ to also emit messages about files that
+were not changed or were ignored due to exclusion patterns. If _Black_ is using a
+configuration file, a blue message detailing which one it is using will be emitted.
+
+```console
+$ black src/ -v
+Using configuration from /tmp/pyproject.toml.
+src/blib2to3 ignored: matches the --extend-exclude regular expression
+src/_black_version.py wasn't modified on disk since last run.
+src/black/__main__.py wasn't modified on disk since last run.
+error: cannot format src/black_primer/cli.py: Cannot parse: 5:6: mport asyncio
+reformatted src/black_primer/lib.py
+reformatted src/blackd/__init__.py
+reformatted src/black/__init__.py
+Oh no! 💥 💔 💥
+3 files reformatted, 2 files left unchanged, 1 file failed to reformat
+```
+
+#### `--version`
+
+You can check the version of _Black_ you have installed using the `--version` flag.
+
+```console
+$ black --version
+black, 23.3.0
+```
+
+#### `--config`
+
+Read configuration options from a configuration file. See
+[below](#configuration-via-a-file) for more details on the configuration file.
+
+#### `-h`, `--help`
+
+Show available command-line options and exit.
+
+### Environment variable options
+
+_Black_ supports the following configuration via environment variables.
+
+#### `BLACK_CACHE_DIR`
+
+The directory where _Black_ should store its cache.
+
+#### `BLACK_NUM_WORKERS`
+
+The number of parallel workers _Black_ should use. The command line option `-W` /
+`--workers` takes precedence over this environment variable.
+
+### Code input alternatives
+
+_Black_ supports formatting code via stdin, with the result being printed to stdout.
+Just let _Black_ know with `-` as the path.
+
+```console
+$ echo "print ( 'hello, world' )" | black -
+print("hello, world")
+reformatted -
+All done! ✨ 🍰 ✨
+1 file reformatted.
+```
+
+**Tip:** if you need _Black_ to treat stdin input as a file passed directly via the CLI,
+use `--stdin-filename`. Useful to make sure _Black_ will respect the `--force-exclude`
+option on some editors that rely on using stdin.
+
+You can also pass code as a string using the `-c` / `--code` option.
+
+### Writeback and reporting
+
+By default _Black_ reformats the files given and/or found in place. Sometimes you need
+_Black_ to just tell you what it _would_ do without actually rewriting the Python files.
+
+There's two variations to this mode that are independently enabled by their respective
+flags:
+
+- `--check` (exit with code 1 if any file would be reformatted)
+- `--diff` (print a diff instead of reformatting files)
+
+Both variations can be enabled at once.
+
+### Output verbosity
+
+_Black_ in general tries to produce the right amount of output, balancing between
+usefulness and conciseness. By default, _Black_ emits files modified and error messages,
+plus a short summary.
+
+```console
+$ black src/
+error: cannot format src/black_primer/cli.py: Cannot parse: 5:6: mport asyncio
+reformatted src/black_primer/lib.py
+reformatted src/blackd/__init__.py
+reformatted src/black/__init__.py
+Oh no! 💥 💔 💥
+3 files reformatted, 2 files left unchanged, 1 file failed to reformat.
+```
+
+The `--quiet` and `--verbose` flags control output verbosity.
projects / etc / vim.git / blobdiff