yq/pkg/yqlib/doc/Union Operator.md

This operator is used to combine different results together.
## Examples
### Combine scalars
Running
```bash
yq eval --null-input '1, true, "cat"'
```
will output
```yaml
1
true
cat
```

### Combine selected paths
Given a sample.yml file of:
```yaml
a: fieldA
b: fieldB
c: fieldC
```
then
```bash
yq eval '.a, .c' sample.yml
```
will output
```yaml
fieldA
fieldC
```

### Combine selected paths
Given a sample.yml file of:
```yaml
a: fieldA
b: fieldB
c: fieldC
```
then
```bash
yq eval '(.a, .c) |= "potatoe"' sample.yml
```
will output
```yaml
a: potatoe
b: fieldB
c: potatoe
```