This operator is used to combine different results together.
## 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
```