Use cleaner lookup instead of grep

roles/libvirt/tasks/main.yml

@@ -21,14 +21,10 @@
     append: yes
     groups: libvirt
 
-- name: Check if 'libvirt libvirt_guest' is in /etc/nsswitch.conf
-  command: grep -c 'libvirt libvirt_guest' /etc/nsswitch.conf
-  register: presence
-  ignore_errors: true
-  changed_when: presence.stdout == '0'
-
 - name: Put 'libvirt libvirt_guest' in /etc/nsswitch.conf
   become: true
+  vars:
+    nsswitch_content: "{{ lookup('file', '/etc/nsswitch.conf') }}"
   lineinfile:
     path: /etc/nsswitch.conf
     regexp: '^hosts: (.+)'
@@ -36,4 +32,4 @@
     state: present
     backrefs: true
     backup: true
-  when: presence.stdout == '0'
+  when: "'libvirt libvirt_guest' not in nsswitch_content"