> cat foo.yaml
---
- xxx: |2
one
two
three
yyy: |
one
two
three
zzz: |
one
two
three
> perl -MYAML::PP -e '$y = YAML::PP->new; print $y->dump_string($y->load_file(shift))' foo.yaml
---
- xxx: |2
one
two
three
yyy: |
one
two
three
zzz: |
one
two
three
See: https://spec.yaml.io/main/playground/parser?input=LS0tCi0geHh4OiB8MgogICAgICBvbmUKICAgICAgdHdvCiAgICAgIHRocmVlCiAgeXl5OiB8CiAgICBvbmUKICAgIHR3bwogICAgdGhyZWUKICB6eno6IHwKICAgIG9uZQogICAgdHdvCiAgICB0aHJlZQo=