Ansible Module lineinfile

External

• https://docs.ansible.com/ansible/latest/modules/lineinfile_module.html

Internal

• Ansible Concepts

Overview

The module is mainly used to look for or change a single line in a text file. A typical use case is to ensure that a particular line is in a file, based on a regular expression. Another case is to replace an existing line using a back-referenced regular expression.

Module Parameters

line (value)

The line to be inserted.

create

Used with state=present. If "yes" os specified, the file will be created if it does not already exist. By default, the value is "no", so the module will fail if the file is missing.

insertafter

Used with state=present. The specified line will be inserted after the last match of the regular expression presented as value of insertafter, or, if the regular expression is not provided, after EOF.

TODO.

Use Cases

Insert a Line to a Text File

- name: Insert a line into a file if it does not exist already
  lineinfile:
    path: test.txt
    line: 'this is a line'
    create: yes

The line will be inserted, but on subsequent executions, the file will not be changed anymore.

Append Lines to a Text File in a Loop

- name: Append lines to a text file
  lineinfile:
    path: test.txt
    line: 'line {{ item }}'
    create: yes
  with_items:
    - A
    - B
    - C

The result will be:

line A
line B
line C

upon the first execution, then the file will not be changes upon subsequent executions.

Adjust a Line based on a Regular Expression

- name: "Adjust Java version to {{ jdk.version }}"
  lineinfile:
    path: "{{ settings_path }}/settings.conf"
    regexp: '^JAVA_VERSION='
    line: "JAVA_VERSION={{ jdk.version }}"