ansible/examples/playbooks/upgraded_vars.yml

# in Ansible 1.2 and later, the $foo variable syntax, which is friendly enough for simple things
# has been upgraded to allow Jinja2 substitiutions as well, which is now the preferred Syntax.
# here is an example.  Note that Jinja2 conditionals belong only in templates.  Use ansible conditionals
# in playbooks.

---

  - hosts: all

    vars:
      a_list:
        - a 
        - b
        - c

    tasks:
      - shell: echo hello {{ ansible_hostname.upper() }}

      - shell: echo match
        when: 2 == 2

      - shell: echo no match
        when: 2 == 2 + 1

      - shell: echo {{ ansible_os_family }}

      - shell: echo {{ item }}
        with_items: a_list

      - shell: echo 'RedHat'
        when: ansible_os_family == 'RedHat'