Configuration

• Explicit start of yaml docs by default (you can disable it with --no-explicit-start)
• Quotes preserved by default (you can disable it with --no-quotes-preserved)
• Arrays elements pushed inwards by default (you can disable it with --no-dash-inwards)
• Output file is input file by default
• Comments preserved by default thanks to ruamel.yaml round_trip mode (you can disable it with --typ safe)

To preserve or not to preserve quotes?

• Quotes preserved means : if there were quotes in the input, they will also be present in the output, and it will be the same type (single/double) of quotes
• Quotes not preserved means :
• if quotes are not necessary (around pure strings), they will be removed
• if quotes are present around booleans and numbers, they will be converted to default (single quotes)
• if quotes are not present around booleans and numbers, there will be no quotes in the output too

For double quotes lovers

Starting with v0.13.0, there is an option, --enforce-double-quotes, to enforce the usage of double quotes when -q or --no-quotes-preserved is used.

Should you use quotes for yaml strings?

If you are wondering if you should use quotes or not when writing yaml code, you can read this awesome Stack Overflow thread.

Quoting the TLDR; section here:

With that being said, according to the official YAML specification one should:

• Whenever applicable use the unquoted style since it is the most readable.
• Use the single-quoted style (') if characters such as " and \ are being used inside the string to avoid escaping them and therefore improve readability.
• Use the double-quoted style (") when the first two options aren't sufficient, i.e. in scenarios where more complex line breaks are required or non-printable characters are needed.

Quotes preserved (default behavior)

With input :

``` yaml
---
apiVersion: extensions/v1beta1 # with comment
kind: ReplicaSet
metadata:
  name: tname
  namespace: tns
  annotations:
    string_no_quotes: frontend
    string_single_quotes: 'frontend'
    string_double_quotes: "frontend"
    boolean_no_quotes: true
    boolean_single_quotes: 'true'
    boolean_double_quotes: "true"
    number_no_quotes: 1
    number_single_quotes: '1'
    number_double_quotes: "1"
```

the output will be the same as the input :

``` yaml
---
apiVersion: extensions/v1beta1 # with comment
kind: ReplicaSet
metadata:
  name: tname
  namespace: tns
  annotations:
    string_no_quotes: frontend
    string_single_quotes: 'frontend'
    string_double_quotes: "frontend"
    boolean_no_quotes: true
    boolean_single_quotes: 'true'
    boolean_double_quotes: "true"
    number_no_quotes: 1
    number_single_quotes: '1'
    number_double_quotes: "1"
```

Quotes not preserved (using -q/--no-quotes-preserved)

With input :

``` yaml
---
apiVersion: extensions/v1beta1 # with comment
kind: ReplicaSet
metadata:
  name: tname
  namespace: tns
  annotations:
    string_no_quotes: frontend
    string_single_quotes: 'frontend'
    string_double_quotes: "frontend"
    boolean_no_quotes: true
    boolean_single_quotes: 'true'
    boolean_double_quotes: "true"
    number_no_quotes: 1
    number_single_quotes: '1'
    number_double_quotes: "1"
```

the output will be :

``` yaml
---
apiVersion: extensions/v1beta1 # with comment
kind: ReplicaSet
metadata:
  name: tname
  namespace: tns
  annotations:
    string_no_quotes: frontend
    string_single_quotes: frontend
    string_double_quotes: frontend
    boolean_no_quotes: true
    boolean_single_quotes: 'true'
    boolean_double_quotes: 'true'
    number_no_quotes: 1
    number_single_quotes: '1'
    number_double_quotes: '1'
```

Quotes not preserved and enforcing double quotes (using -q/--no-quotes-preserved and -E/--enforce-double-quotes)

With input :

``` yaml
---
apiVersion: extensions/v1beta1 # with comment
kind: ReplicaSet
metadata:
  name: tname
  namespace: tns
  annotations:
    string_no_quotes: frontend
    string_single_quotes: 'frontend'
    string_double_quotes: "frontend"
    boolean_no_quotes: true
    boolean_single_quotes: 'true'
    boolean_double_quotes: "true"
    number_no_quotes: 1
    number_single_quotes: '1'
    number_double_quotes: "1"
```

the output will be :

``` yaml
---
apiVersion: extensions/v1beta1 # with comment
kind: ReplicaSet
metadata:
  name: tname
  namespace: tns
  annotations:
    string_no_quotes: frontend
    string_single_quotes: frontend
    string_double_quotes: frontend
    boolean_no_quotes: true
    boolean_single_quotes: "true"
    boolean_double_quotes: "true"
    number_no_quotes: 1
    number_single_quotes: "1"
    number_double_quotes: "1"
```