When working with Ansible playbooks, you might encounter a frustrating YAML parsing error when trying to handle strings containing colons. The issue stems from YAML's interpretation of colons as key-value separators in its native syntax.

In your example:

---
- hosts: all
  tasks:
    - raw: echo "something: else"
  register: progOutput

YAML interprets the colon after "raw:" as a key-value delimiter, then gets confused when it encounters another colon in the string. This creates a parsing conflict.

Method 1: Quote the Entire Argument

The most reliable solution is to properly quote the entire argument string:

---
- hosts: all
  tasks:
    - raw: 'echo "something: else"'
  register: progOutput

Method 2: Use Block Scalar Syntax

For more complex cases, YAML's block scalar syntax works well:

---
- hosts: all
  tasks:
    - raw: |
        echo "something: else"
  register: progOutput

Method 3: JSON-style Quoting

You can also use double quotes with escaped inner quotes:

---
- hosts: all
  tasks:
    - raw: "echo \"something: else\""
  register: progOutput

For your comparison task, here's the corrected version:

---
- hosts: all
  tasks:
    - raw: 'echo "something: else"'
      register: progOutput

    - debug:
        msg: "something else happened!"
      when: progOutput.stdout_lines[-1] != "something: else"

When dealing with variables containing colons, use the same quoting principles:

---
- hosts: all
  vars:
    my_string: "key: value"
  
  tasks:
    - debug:
        msg: "The string is {{ my_string }}"

• Always quote strings containing special YAML characters
• Prefer single quotes for simple cases
• Use block scalar syntax for multi-line commands
• Be consistent with your quoting style throughout the playbook
• Test your playbook with ansible-playbook --syntax-check

---

When working with Ansible playbooks, a common stumbling block arises when dealing with command outputs containing colons. The YAML parser interprets colons as key-value separators, which causes syntax errors when they appear in command outputs or strings.

The root issue lies in YAML's parsing rules. In your example:

tasks:
  - raw: echo "something: else"

The colon after "something" makes YAML expect a value, creating a parsing conflict with the raw module's syntax.

Here are several robust approaches to handle colons in Ansible commands:

1. Using the Pipe Character for Literal Blocks

tasks:
  - raw: |
      echo "something: else"

2. Proper YAML Quoting

tasks:
  - raw: "echo \"something: else\""

3. Variable Substitution

vars:
  expected_output: "something: else"

tasks:
  - raw: "echo \"{{ expected_output }}\""
  register: progOutput

When checking output containing colons:

- debug:
    msg: "Output didn't match!"
  when: progOutput.stdout_lines[-1] != expected_output

For complex scenarios with various special characters:

tasks:
  - shell: |
      echo "complex:string with:multiple:colons"
    args:
      executable: /bin/bash
  register: output

- debug:
    var: output.stdout

• Always test playbooks with --syntax-check flag
• Use | for multi-line commands
• Prefer the shell module over raw when possible
• Store complex strings in variables