Ubuntu update manager for Fabric. Checks for updates, installs them and reboots if needed across multiple servers

fabfile.py

"""
Ubuntu update manager for Fabric

Checks for updates, installs them and reboots if needed across multiple servers

Create a "hosts" file alongside this fabfile and put your hosts in there one per line

Updating package list::

    fab update

Check for updates::

    fab check

Install updates and reboot (if necessary)::

    fab upgrade

"""
from fabric.api import sudo, run, env
from fabric.colors import red
from fabric.contrib.files import exists
from fabric.contrib.console import confirm


for host in open('hosts').readlines():
    host = host.strip()
    if host.startswith('#'):
        continue
    env.hosts.append(host)

def update():
    """
    Updates the package list
    """
    sudo('apt-get update -qq')

def check():
    """
    Displays package updates needed
    """
    run("""apt-get dist-upgrade -s | python -c "import sys; [sys.stderr.write(l) for l in sys.stdin.readlines()[7:] if not (l.startswith('Inst') or l.startswith('Conf'))]" """)

def upgrade():
    """
    Upgrades the system, updating packages and reboots if needed
    """
    sudo('apt-get -y upgrade')
    if exists('/var/run/reboot-required') and confirm('Needs reboot, do it now?'):
        print(red('Rebooting now', True))
        sudo('reboot')

A file object is already an iterator over lines in Python. You don't need .readlines() call