Edit single-line text -Ansible module lineinfile

How to edit a single-line text in a file with Ansible module lineinfile.

August 19, 2021

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#ansible #lineinfile #module #text #rhel #centos #fedora #ubuntu #debian #suse

Today we’re going to talk about how to edit a single-line text in a file with Ansible. Ansible module lineinfile. I’m Luca Berton and welcome to today’s episode of Ansible Pilot

Ansible module lineinfile

Today we’re talking about the Ansible module lineinfile. The full name is ansible.builtin.lineinfile, which means that is part of the collection of modules “builtin” with ansible and shipped with it. It’s a module pretty stable and out for years and it supports a large variety of operating systems. You are able to insert, update and remove a single line of text in a file.

Main Parameters

path string - file path
line string - text
insertafter/insertbefore string - EOF/regular expression
validate string - validation command
create boolean - create if not exist
state string - present/absent
owner/group/mode - permission
setype/seuser/selevel - SELinux

This module has some parameters to perform any tasks. The only required is “path”, where you specify the filesystem path of the file you’re going to edit. “line” is the line of text we would like to insert in the file, easy! By default, the text is going to be inserted at the end of the file, but we could personalize it in a specific position with “insertafter” or “insertbefore”. If there is any tool to validate the file we could specify it in the validate parameter, very useful for configuration files. If the file does not exist we could also “create” it! Usually, we would like to insert a text line but we could also remove using state in conjunction with parameter absent. Let me also highlight that we could also specify some permissions or SELinux property.

demo

Are you ready to make your hands dirty? Let’s jump in a live demo of lineinfile module usage in the Ansible playbook.

lineinfile.yml

---
- name: lineinfile module demo
  hosts: all
  become: true
  tasks:
    - name: allow password authentication
      ansible.builtin.lineinfile:
        state: present
        dest: /etc/ssh/sshd_config
        regexp: "^PasswordAuthentication"
        line: "PasswordAuthentication yes"
        validate: 'sshd -t -f %s'

code with ❤️ in GitHub

Recap

Now you know better the Ansible module lineinfile and you could use it successfully in your playbook. Subscribe to the YouTube channel, Medium, and Website, X (formerly Twitter) to not miss the next episode of the Ansible Pilot.