Gotcha: YAML multiline strings and unexpected parsing

YAML multiline strings behave differently depending on syntax, causing unexpected trailing newlines, preserved indentation, or folded lines.

YAML multiline string types:

# 1. LITERAL BLOCK (|) - preserves newlines
script: |
  echo hello
  echo world
# Result: "echo hello\necho world\n"
# (Keeps newlines, adds trailing newline)

# 2. LITERAL BLOCK STRIP (|-) - no trailing newline
script: |-
  echo hello
  echo world
# Result: "echo hello\necho world"
# (Keeps newlines, NO trailing newline)

# 3. LITERAL BLOCK KEEP (|+) - keep all trailing newlines
script: |+
  echo hello
  echo world


# Result: "echo hello\necho world\n\n\n"

# 4. FOLDED BLOCK (>) - newlines become spaces
description: >
  This is a long
  description that will
  be folded into one line.
# Result: "This is a long description that will be folded into one line.\n"

# 5. FOLDED BLOCK STRIP (>-)
description: >-
  This is a long
  description.
# Result: "This is a long description."
# (Folded, no trailing newline)

# COMMON GOTCHAS:

# Gotcha 1: Indentation matters!
data: |
  line 1
    indented line  # This has 2 extra spaces!
  line 3

# Gotcha 2: YAML booleans
# These are ALL booleans, not strings!
flag: yes    # true
flag: no     # false  
flag: true   # true
flag: on     # true
flag: off    # false
flag: "yes"  # string "yes" (quote to force string)

# Gotcha 3: Numbers
version: 1.0   # float, not string!
version: "1.0" # string (quote it)
zip: 01onal   # string
zip: 01234    # octal number in some parsers!
zip: "01234"  # string (always quote zip codes)

# Gotcha 4: Colons in values
title: Thing: A Story  # ERROR! Colon starts a mapping
title: "Thing: A Story" # Correct

YAML's implicit typing and multiple string syntaxes cause subtle bugs. The Norway problem (NO parsed as false) and colon-in-value errors are especially common.

Configuration files in YAML format