How to Fix 'Permission Denied' Error on Docker Daemon Socket in Linux

Linux users running Docker commands may encounter a 'permission denied' error when trying to connect to the Docker daemon socket at /var/run/docker.sock, because the socket is accessible only to root and members of the docker group. The permanent fix is to add your user account to the docker group using 'sudo usermod -aG docker $USER', after which Docker commands work without sudo. A new login session must be started for the group membership change to take effect, since existing shell sessions retain the old group list. A quick but temporary workaround is to prefix commands with sudo, though this is not recommended for regular use. Users should avoid the commonly suggested 'chmod 666' fix, as it exposes the Docker socket to all users and processes on the machine, creating a serious security risk.