> Don't forget the **quotes** around the globs! The quotes make sure that Prettier CLI expands the globs rather than your shell, which is important for cross-platform usage.
Prettier CLI uses the [glob syntax from the `fast-glob` module](https://github.com/mrmlnc/fast-glob#pattern-syntax). To escape special glob characters, one of the two escaping syntaxes can be used: `prettier "\[my-dir]/*.js"` or `prettier "[[]my-dir]/*.js"`. Both match all JS files in a directory named `[my-dir]`, however the latter syntax is preferable as the former doesn't work on Windows, where backslashes are treated as path separators.
Prettier CLI will ignore files located in `node_modules` directory. To opt out from this behavior use `--with-node-modules` flag.
Since file names in Linux can contain almost any characters, before resolving a glob pattern, Prettier CLI first treats it as a literal file name. If a file with such a name is found, Prettier CLI proceeds with that file and doesn't resolve the pattern as a glob.
When you want to check if your files are formatted, you can run Prettier with the `--check` flag (or `-c`).
This will output a human-friendly message and a list of unformatted files, if any.
```bash
prettier --check "src/**/*.js"
```
Console output if all files are formatted:
```
Checking formatting...
All matched files use Prettier code style!
```
Console output if some of the files require re-formatting:
```
Checking formatting...
src/fileA.js
src/fileB.js
Code style issues found in the above file(s). Forgot to run Prettier?
```
The command will return exit code 1 in the second case, which is helpful inside the CI pipelines.
Human-friendly status messages help project contributors react on possible problems.
To minimise the number of times `prettier --check` finds unformatted files, you may be interested in configuring a [pre-commit hook](precommit.md) in your repo.
Applying this practice will minimise the number of times the CI fails because of code formatting problems.
If you need to pipe the list of unformatted files to another command,you can use [`--list-different`](cli.md#--list-different) flag instead of `--check`.
If you're worried that Prettier will change the correctness of your code, add `--debug-check` to the command. This will cause Prettier to print an error message if it detects that code correctness might have changed. Note that `--write` cannot be used with `--debug-check`.
If you are repeatedly formatting individual files with `prettier`, you will incur a small performance cost when prettier attempts to look up a [configuration file](configuration.md). In order to skip this, you may ask prettier to find the config file once, and re-use it later on.
Another useful flag is `--list-different` (or `-l`) which prints the filenames of files that are different from Prettier formatting. If there are differences the script errors out, which is useful in a CI scenario.
You can also use [`--check`](cli.md#--check) flag, which works the same way as `--list-different`, but also prints a human-friendly summary message to stdout.
