---
description: |
  The `packer fmt` Packer command formats HCL2 configuration files to a canonical format and style to help you prevent coding errors.
page_title: packer fmt command reference
---

# `packer fmt` command reference

The `packer fmt` Packer command is used to format HCL2 configuration files to
a canonical format and style. JSON files (.json) are not modified. This command
applies a subset of HCL language style conventions, along with other minor
adjustments for readability.

`packer fmt` will display the name of the configuration file(s) that need formatting,
and write any formatted changes back to the original configuration file(s).

Example usage:

Check if configuration file(s) need to be formatted, but don't write the changes.

```shell-session
$ packer fmt -check .
my-template.pkr.hcl

```

Format a configuration file, writing the changes back to the original file.

```shell-session
$ packer fmt my-template.pkr.hcl
my-template.pkr.hcl

```

Format multiple configuration files, writing the changes back to respective original files.

```shell-session
$ packer fmt my-template.pkr.hcl my-varfile.pkrvars.hcl
my-template.pkr.hcl
my-varfile.pkrvars.hcl

```

Format a configuration file, reading from stdin and writing to stdout.

```shell-session
$ packer fmt -

// You can use pipes to combine this feature with other command line options
$ cat my-template.pkr.hcl | packer fmt -
```

## Options

- `-check` - Checks if the input is formatted. Exit status will be 0 if all
  input is properly formatted and non-zero otherwise.

- `-diff` - Display diffs of any formatting change

- `-write=false` - Don't write formatting changes to source files
  (always disabled if using -check)

- `-` - read formatting changes from stdin and write them to stdout.

- `-recursive` Also process files in subdirectories. By default, only the
  given directory (or current directory) is processed.
