Resolving the Error WARNING:root:could not open file /etc/apt/sources.list on Debian Systems


Hello enthusiasts! In this post, we’re going to delve into a common error that Debian system administrators sometimes come across: “WARNING:root:could not open file /etc/apt/sources.list “. By the end of this reading, you’ll not only identify the root of this issue but also have step by step guidelines on how to solve it using ‘su’ command.

Problem Identification

This error typically implies that the system is having trouble accessing the /etc/apt/sources.list file, which is essential for package installation. This file holds the information about available repositories from where the system can install or update software packages. But what leads to this it being inaccessible?

  • Inadequate permissions: The root user (superuser) can read, write and execute this file. If another user without these rights tries to access it, they’ll be denied, and the error in question is thrown.
  • Non-existent or incorrect path: If the file does not exist or the location defined is incorrect, the system will naturally throw an error as well.

Solution – Using ‘su’

To resolve this issue, you ideally need to have superuser (root) access. ‘su’ is a command in Linux that allows you to switch to the root or any other specified user. However, the following steps assume that you already have the root password at hand.

Step 1: Switch to root user

In your console, enter the command su. Follow this by inputting the root password when prompted.

Step 2: Check if the file exists

Use the command ls /etc/apt/sources.list. If the system returns ‘/etc/apt/sources.list’, it means the file exists. If not, you need to create it using the below command.

Step 3: Create the file if it does not exist

Launch a text editor, let’s assume nano, to make an empty file by typing nano /etc/apt/sources.list. Save and exit nano by pressing ctrl + x and confirming the save.

Step 4: Assign the correct permissions

Provided the file exists, use chmod to set suitable permissions. For example, type chmod 644 /etc/apt/sources.list, granting Read and Write permissions to the owner (root), and only Read to everyone else.

Step 5: Test to verify

Try updating the system by using apt-get update. If executed successfully, with no errors, it signifies that the file is accessible and has the correct permissions thus problem solved.


Effectively identifying and resolving such errors is a crucial skill for a system administrator using Debian. I hope this article was helpful in your journey for the same. Till next time, keep exploring!

Author: admin

Leave a Reply

Your email address will not be published. Required fields are marked *