yq/pkg/yqlib/doc/operators/load.md

# Load

The load operators allows you to load in content from another file.

Note that you can use string operators like `+` and `sub` to modify the value in the yaml file to a path that exists in your system.

You can load files of the following supported types:

|Format | Load Operator |
| --- | --- |
| Yaml | load |
| XML | load_xml |
| Properties | load_props |
| Plain String | load_str |

Lets say there is a file `../../examples/thing.yml`:

```yaml
a: apple is included
b: cool
```
and a file `small.xml`:

```xml
<this>is some xml</this>
```

and `small.properties`:

```properties
this.is = a properties file
```

{% hint style="warning" %}
Note that versions prior to 4.18 require the 'eval/e' command to be specified.&#x20;

`yq e <exp> <file>`
{% endhint %}

## Simple example
Given a sample.yml file of:
```yaml
myFile: ../../examples/thing.yml
```
then
```bash
yq 'load(.myFile)' sample.yml
```
will output
```yaml
a: apple is included
b: cool.
```

## Replace node with referenced file
Note that you can modify the filename in the load operator if needed.

Given a sample.yml file of:
```yaml
something:
  file: thing.yml
```
then
```bash
yq '.something |= load("../../examples/" + .file)' sample.yml
```
will output
```yaml
something:
  a: apple is included
  b: cool.
```

## Replace _all_ nodes with referenced file
Recursively match all the nodes (`..`) and then filter the ones that have a 'file' attribute. 

Given a sample.yml file of:
```yaml
something:
  file: thing.yml
over:
  here:
    - file: thing.yml
```
then
```bash
yq '(.. | select(has("file"))) |= load("../../examples/" + .file)' sample.yml
```
will output
```yaml
something:
  a: apple is included
  b: cool.
over:
  here:
    - a: apple is included
      b: cool.
```

## Replace node with referenced file as string
This will work for any text based file

Given a sample.yml file of:
```yaml
something:
  file: thing.yml
```
then
```bash
yq '.something |= load_str("../../examples/" + .file)' sample.yml
```
will output
```yaml
something: |-
  a: apple is included
  b: cool.
```

## Load from XML
Given a sample.yml file of:
```yaml
cool: things
```
then
```bash
yq '.more_stuff = load_xml("../../examples/small.xml")' sample.yml
```
will output
```yaml
cool: things
more_stuff:
  this: is some xml
```

## Load from Properties
Given a sample.yml file of:
```yaml
cool: things
```
then
```bash
yq '.more_stuff = load_props("../../examples/small.properties")' sample.yml
```
will output
```yaml
cool: things
more_stuff:
  this:
    is: a properties file
```

## Merge from properties
This can be used as a convenient way to update a yaml document

Given a sample.yml file of:
```yaml
this:
  is: from yaml
  cool: ay
```
then
```bash
yq '. *= load_props("../../examples/small.properties")' sample.yml
```
will output
```yaml
this:
  is: a properties file
  cool: ay
```