Ansible Lineinfile | Everything

Let's learn more about Ansible's Lineinfile feature. We at Skynats can take care of your Ansible problems with our Server Management Services.

Lineinfile in Ansible

Ansible's lineinfile module modifies a single line in a file. It is helpful to add a new line, alter or replace an existing one, and delete a line from a file after finding a specific text. We can apply search criteria when working with this module by using a regular expression.

Three topics will be examined in this article, namely:

• Inserting a line into a file

• Removing a line from a file

• Changing a line in a file

Inserting a line into a file

The path of the file that needs to be changed can be specified using the path/dest parameter. And specify the line we need to insert using the line parameter.

In the following example, "Inserting a line in a file" will be added to the file "server.txt." The new line will now have the EOF. If the line already exists, it will not combine. The program is prompted to create a new file if the one requested is missing when the create parameter is set. Present is the default value for the state.

E.g

- hosts: loc  

  tasks:  

    - name: Ansible insert lineinfile   

      lineinfile:  

        dest: /home/javaTpoint/remote_server.txt  

        line: Inserting a line in a file.  

        state: present  

        create: yes

Removing a line from a file

Either remove that particular line or set the state parameter to Absent. No other place will have the line.

E.g

- hosts: loc  

  tasks:  

    - name: Ansible lineinfile remove the line  

      lineinfile:  

        dest: /home/javaTpoint/remote_server.txt  

        line: Removed lines.  

        state: absent

Changing a line in a file

Along with the state of Present, we must also use the Ansible backrefs and regexp parameters. If no lines are matched by the regexp, the file will not be altered. The last matching line will be replaced if the regexp matches one or more lines. The grouped elements of a regexp are filled in and can be altered.

E.g

In the example below, we are making a line-by-line comment. By putting them inside the parenthesis to "1," the entire line is captured. The line is replaced by '#1' and then what was captured. We can have multiple captures and identify them using "1," "2," "3," etc.

Using Ansible lineinfile backrefs to comment a line

- name: Ansible lineinfile regexp replace the example  
  lineinfile:  
    dest: /etc/ansible/ansible.cfg  
    regexp: '(inventory = /home/fedora/inventory.ini.*)'  
    line: '#\1'  
    backrefs: yes

By using lineinfile regexp, the line is uncommented.

- name: Ansible lineinfile backrefs example  
  lineinfile:  
    dest: /etc/ansible/ansible.cfg  
    regexp: '#(inventory = /home/fedora/inventory.ini.*)'  
    line: '\1'  
    backrefs: yes

Conclusion

The Lineinfile module in Ansible is briefly described in this article. We also provided instructions on how to use lineinfile to add, delete, and modify text.