+[//]: # "NOTE: THIS FILE WAS AUTOGENERATED FROM README.md"
+
+# Installation and usage
+
+## Installation
+
+_Black_ can be installed by running `pip install black`. It requires Python 3.6.0+ to
+run but you can reformat Python 2 code with it, too.
+
+### Install from GitHub
+
+If you can't wait for the latest _hotness_ and want to install from GitHub, use:
+
+`pip install git+git://github.com/psf/black`
+
+## Usage
+
+To get started right away with sensible defaults:
+
+```sh
+black {source_file_or_directory}
+```
+
+You can run _Black_ as a package if running it as a script doesn't work:
+
+```sh
+python -m black {source_file_or_directory}
+```
+
+## Command line options
+
+_Black_ doesn't provide many options. You can list them by running `black --help`:
+
+```text
+Usage: black [OPTIONS] [SRC]...
+
+ The uncompromising code formatter.
+
+Options:
+ -c, --code TEXT Format the code passed in as a string.
+ -l, --line-length INTEGER How many characters per line to allow.
+ [default: 88]
+
+ -t, --target-version [py27|py33|py34|py35|py36|py37|py38]
+ Python versions that should be supported by
+ Black's output. [default: per-file auto-
+ detection]
+
+ --pyi Format all input files like typing stubs
+ regardless of file extension (useful when
+ piping source on standard input).
+
+ -S, --skip-string-normalization
+ Don't normalize string quotes or prefixes.
+ --check Don't write the files back, just return the
+ status. Return code 0 means nothing would
+ change. Return code 1 means some files
+ would be reformatted. Return code 123 means
+ there was an internal error.
+
+ --diff Don't write the files back, just output a
+ diff for each file on stdout.
+
+ --color / --no-color Show colored diff. Only applies when
+ `--diff` is given.
+
+ --fast / --safe If --fast given, skip temporary sanity
+ checks. [default: --safe]
+
+ --include TEXT 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.
+ [default: \.pyi?$]
+
+ --exclude TEXT 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. [default: /(\.eggs|\.git|\.hg|\.mypy
+ _cache|\.nox|\.tox|\.venv|\.svn|_build|buck-
+ out|build|dist)/]
+
+ --force-exclude TEXT Like --exclude, but files and directories
+ matching this regex will be excluded even
+ when they are passed explicitly as arguments
+
+ -q, --quiet Don't emit non-error messages to stderr.
+ Errors are still emitted; silence those with
+ 2>/dev/null.
+
+ -v, --verbose Also emit messages to stderr about files
+ that were not changed or were ignored due to
+ --exclude=.
+
+ --version Show the version and exit.
+ --config FILE Read configuration from FILE path.
+ -h, --help Show this message and exit.
+```
+
+_Black_ is a well-behaved Unix-style command-line tool:
+
+- it does nothing if no sources are passed to it;
+- it will read from standard input and write to standard output if `-` is used as the
+ filename;
+- it only outputs messages to users on standard error;
+- exits with code 0 unless an internal error occurred (or `--check` was used).
+
+## Using _Black_ with other tools
+
+While _Black_ enforces formatting that conforms to PEP 8, other tools may raise warnings
+about _Black_'s changes or will overwrite _Black_'s changes. A good example of this is
+[isort](https://pypi.org/p/isort). Since _Black_ is barely configurable, these tools
+should be configured to neither warn about nor overwrite _Black_'s changes.
+
+Actual details on _Black_ compatible configurations for various tools can be found in
+[compatible_configs](https://github.com/psf/black/blob/master/docs/compatible_configs.md).
+
+## Migrating your code style without ruining git blame
+
+A long-standing argument against moving to automated code formatters like _Black_ is
+that the migration will clutter up the output of `git blame`. This was a valid argument,
+but since Git version 2.23, Git natively supports
+[ignoring revisions in blame](https://git-scm.com/docs/git-blame#Documentation/git-blame.txt---ignore-revltrevgt)
+with the `--ignore-rev` option. You can also pass a file listing the revisions to ignore
+using the `--ignore-revs-file` option. The changes made by the revision will be ignored
+when assigning blame. Lines modified by an ignored revision will be blamed on the
+previous revision that modified those lines.
+
+So when migrating your project's code style to _Black_, reformat everything and commit
+the changes (preferably in one massive commit). Then put the full 40 characters commit
+identifier(s) into a file.
+
+```
+# Migrate code style to Black
+5b4ab991dede475d393e9d69ec388fd6bd949699
+```
+
+Afterwards, you can pass that file to `git blame` and see clean and meaningful blame
+information.
+
+```console
+$ git blame important.py --ignore-revs-file .git-blame-ignore-revs
+7a1ae265 (John Smith 2019-04-15 15:55:13 -0400 1) def very_important_function(text, file):
+abdfd8b0 (Alice Doe 2019-09-23 11:39:32 -0400 2) text = text.lstrip()
+7a1ae265 (John Smith 2019-04-15 15:55:13 -0400 3) with open(file, "r+") as f:
+7a1ae265 (John Smith 2019-04-15 15:55:13 -0400 4) f.write(formatted)
+```
+
+You can even configure `git` to automatically ignore revisions listed in a file on every
+call to `git blame`.
+
+```console
+$ git config blame.ignoreRevsFile .git-blame-ignore-revs
+```
+
+**The one caveat is that GitHub and GitLab do not yet support ignoring revisions using
+their native UI of blame.** So blame information will be cluttered with a reformatting
+commit on those platforms. (If you'd like this feature, there's an open issue for
+[GitLab](https://gitlab.com/gitlab-org/gitlab/-/issues/31423) and please let GitHub
+know!)
+
+## NOTE: This is a beta product
+
+_Black_ is already [successfully used](#used-by) by many projects, small and big. It
+also sports a decent test suite. However, it is still very new. Things will probably be
+wonky for a while. This is made explicit by the "Beta" trove classifier, as well as by
+the "b" in the version number. What this means for you is that **until the formatter
+becomes stable, you should expect some formatting to change in the future**. That being
+said, no drastic stylistic changes are planned, mostly responses to bug reports.
+
+Also, as a temporary safety measure, _Black_ will check that the reformatted code still
+produces a valid AST that is equivalent to the original. This slows it down. If you're
+feeling confident, use `--fast`.
projects / etc / vim.git / blobdiff