```
yq p <yaml_file> <path>
```

Prefixes a yaml document with the given path expression. The complete yaml content will be nested inside the new prefix path.

See docs for [path expression](path_expressions.md) for more details.

## Prefix a document
Given a data1.yaml file of:
```yaml
a:
  b: [1, 2]
```
then
```bash
yq p data1.yaml c.d
```
will output:
```yaml
c:
  d:
    a:
      b: [1, 2]
```

## Updating files in-place
```bash
yq p -i data1.yaml c
```
will update the data1.yaml file so that the path 'c' prefixes the document.

## Multiple Documents
### Prefix a single document
Given a data1.yaml file of:
```yaml
something: else
---
a: simple
b: cat
```
then
```bash
yq p -d1 data1.yaml c
```
will output:
```yaml
something: else
---
c:
  a: simple
  b: cat
```

### Prefix all documents
Given a data1.yaml file of:
```yaml
something: else
---
a: simple
b: cat
```
then
```bash
yq p -d'*' data1.yaml c
```
will output:
```yaml
c:
  something: else
---
c:
  a: simple
  b: cat
```