An if statement in Jinja has the following structure.

{% if condition %}
  <do something>
{% elif condition %}
  <do something>
{% else %}
  <do something>
{% endif %}

For example.

{% if foo == 'Hello' %}
  print("foo equals Hello")
{% elif foo == 'World' %}
  print("foo equals World")
{% else %}
  print("foo does not equal Hello or World")
{% endif %}

Here is how you would use an or clause.

{% if foo == 'Hello' or foo == 'World' %}
  print("foo equals Hello or World")
{% else %}
  print("foo does not equal Hello or World")
{% endif %}

Including a single dash after the leading percentage character (%-) and a single dash before the trailing percentage character (-%) should do a trim, removing whitespace from the left and right of the value.

{%- if foo == 'Hello' or foo == 'World' -%}
  print(" foo equals Hello or World ")
{%- else -%}
  print(" foo does not equal Hello or World ")
{%- endif -%}

Following are command if statements.