YAML Block Chomping Indicators: | vs |- vs |+

yaml-chomping-indicators.md

YAML Block Chomping Indicators: | vs |- vs |+

The | symbol denotes a literal block scalar — newlines inside the value are preserved as-is. The character after it is the block chomping indicator, controlling how trailing newlines are handled.

The Three Indicators

Indicator	Name	Trailing newline
|	Clip (default)	Keeps one trailing newline
|-	Strip	Removes all trailing newlines
|+	Keep	Preserves all trailing newlines

Internal newlines (between lines of content) are always preserved — chomping only affects trailing newlines after the last line.

Demo

clip: |
  hello
  world

strip: |-
  hello
  world

keep: |+
  hello
  world

import yaml

data = yaml.safe_load("""
clip: |
  hello
  world

strip: |-
  hello
  world

keep: |+
  hello
  world


""")

for key, value in data.items():
    print(f"{key!r}: {value!r}")

Output:

'clip':  'hello\nworld\n'
'strip': 'hello\nworld'
'keep':  'hello\nworld\n\n\n'

Visualized with · representing a newline:

Indicator	Value
| clip	hello·world·
|- strip	hello·world
|+ keep	hello·world···

Practical Notes

• Raw base64 / certificates → use |- to avoid a trailing \n that can break strict decoders
• PEM certificates (with -----BEGIN/END----- headers) → | is fine; most PEM parsers are lenient
• Kubernetes secrets/manifests, Helm charts → |- is the safe default for any cert or key material

Reference

• YAML 1.2 Spec — Block Chomping