Only check whether a line present in a file (ansible)

Question

In ansible, I need to check whether a particular line present in a file or not. Basically, I need to convert the following command to an ansible task. My goal is to only che

Answer 1

Another solution, also useful for other purposes is to loop over the contents of the file, line by line

- name: get the file
  slurp:
    src: /etc/locale.gen
  register: slurped_file

- name: initialize the matches list
  set_fact:
    MATCHES: []

- name: collect matches in a list
  set_fact:
    MATCHES: "{{ MATCHES + [line2match] }}"
  loop: "{{ file_lines }}"
  loop_control:
    loop_var: line2match
  vars:
    - decode_content: "{{ slurped_file.content | b64decode }}"
    - file_lines: "{{ decode_content.split('\n') }}"
  when: '"BE" in line2match'
  
- name: report matches if any
  debug:
    msg: "Found {{ MATCHES | length }} matches\n{{ MATCHES }}"
  when: 'listlen | int > 0'
  vars:
    listlen: "{{ MATCHES | length }}"

This mechanism can be use to get a specific value from a matched line if you use it for example with the jinja regex_replace filter

Answer 2

Use ansible lineinfile command, but this command will update the file with the line if it does not exists.

- lineinfile: dest=/tmp/my.conf line='127.0.0.1' state=present