MOTD.sh

#!/bin/sh

# install figlet to enable ASCII art
apt-get install figlet
# create directory
mkdir /etc/update-motd.d/
# change to new directory
cd /etc/update-motd.d/
# create dynamic files
touch 00-header && touch 10-sysinfo && touch 20-updates && touch 90-footer
# make files executable
chmod +x /etc/update-motd.d/*
# remove MOTD file
rm /etc/motd
# symlink dynamic MOTD file
ln -s /var/run/motd /etc/motd

cat <<EOF >> 00-header
#!/bin/sh
#
#    00-header - create the header of the MOTD
#    Copyright (c) 2013 Nick Charlton
#    Copyright (c) 2009-2010 Canonical Ltd.
#
#    Authors: Nick Charlton <hello@nickcharlton.net>
#             Dustin Kirkland <kirkland@canonical.com>
#
#    This program is free software; you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation; either version 2 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License along
#    with this program; if not, write to the Free Software Foundation, Inc.,
#    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

[ -r /etc/lsb-release ] && . /etc/lsb-release

if [ -z "$DISTRIB_DESCRIPTION" ] && [ -x /usr/bin/lsb_release ]; then
        # Fall back to using the very slow lsb_release utility
        DISTRIB_DESCRIPTION=$(lsb_release -s -d)
fi

figlet $(hostname)
printf "\n"

printf "Welcome to %s (%s).\n" "$DISTRIB_DESCRIPTION" "$(uname -r)"
printf "\n"
EOF

cat <<EOF >> 10-sysinfo
#!/bin/bash
#
#    10-sysinfo - generate the system information
#    Copyright (c) 2013 Nick Charlton
#
#    Authors: Nick Charlton <hello@nickcharlton.net>
#
#    This program is free software; you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation; either version 2 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License along
#    with this program; if not, write to the Free Software Foundation, Inc.,
#    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

date=`date`
load=`cat /proc/loadavg | awk '{print $1}'`
root_usage=`df -h / | awk '/\// {print $(NF-1)}'`
memory_usage=`free -m | awk '/Mem:/ { total=$2 } /buffers\/cache/ { used=$3 } END { printf("%3.1f%%", used/total*100)}'`
swap_usage=`free -m | awk '/Swap/ { printf("%3.1f%%", "exit !$2;$3/$2*100") }'`
users=`users | wc -w`
time=`uptime | grep -ohe 'up .*' | sed 's/,/\ hours/g' | awk '{ printf $2" "$3 }'`
processes=`ps aux | wc -l`
ip=`ifconfig $(route | grep default | awk '{ print $8 }') | grep "inet addr" | awk -F: '{print $2}' | awk '{print $1}'`

echo "System information as of: $date"
echo
printf "System load:\t%s\tIP Address:\t%s\n" $load $ip
printf "Memory usage:\t%s\tSystem uptime:\t%s\n" $memory_usage "$time"
printf "Usage on /:\t%s\tSwap usage:\t%s\n" $root_usage $swap_usage
printf "Local Users:\t%s\tProcesses:\t%s\n" $users $processes
echo
EOF

cat <<EOF >> 20-updates
#!/usr/bin/python
#
#   20-updates - create the system updates section of the MOTD
#   Copyright (c) 2013 Nick Charlton
#
#   Authors: Nick Charlton <hello@nickcharlton.net>
#   Based upon prior work by Dustin Kirkland and Michael Vogt.
#
#   This program is free software; you can redistribute it and/or modify
#   it under the terms of the GNU General Public License as published by
#   the Free Software Foundation; either version 2 of the License, or
#   (at your option) any later version.
#
#   This program is distributed in the hope that it will be useful,
#   but WITHOUT ANY WARRANTY; without even the implied warranty of
#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#   GNU General Public License for more details.
#
#   You should have received a copy of the GNU General Public License along
#   with this program; if not, write to the Free Software Foundation, Inc.,
#   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

import sys
import subprocess
import apt_pkg

DISTRO = subprocess.Popen(["lsb_release", "-c", "-s"],
                          stdout=subprocess.PIPE).communicate()[0].strip()

class OpNullProgress(object):
    '''apt progress handler which supresses any output.'''
    def update(self):
        pass
    def done(self):
        pass

def is_security_upgrade(pkg):
    '''
    Checks to see if a package comes from a DISTRO-security source.
    '''
    security_package_sources = [("Ubuntu", "%s-security" % DISTRO),
                               ("Debian", "%s-security" % DISTRO)]

    for (file, index) in pkg.file_list:
        for origin, archive in security_package_sources:
            if (file.archive == archive and file.origin == origin):
                return True
    return False

# init apt and config
apt_pkg.init()

# open the apt cache
try:
    cache = apt_pkg.Cache(OpNullProgress())
except SystemError, e:
    sys.stderr.write("Error: Opening the cache (%s)" % e)
    sys.exit(-1)

# setup a DepCache instance to interact with the repo
depcache = apt_pkg.DepCache(cache)

# take into account apt policies
depcache.read_pinfile()

# initialise it
depcache.init()

# give up if packages are broken
if depcache.broken_count > 0:
    sys.stderr.write("Error: Broken packages exist.")
    sys.exit(-1)

# mark possible packages
try:
    # run distro-upgrade
    depcache.upgrade(True)
    # reset if packages get marked as deleted -> we don't want to break anything
    if depcache.del_count > 0:
        depcache.init()

    # then a standard upgrade
    depcache.upgrade()
except SystemError, e:
    sys.stderr.write("Error: Couldn't mark the upgrade (%s)" % e)
    sys.exit(-1)

# run around the packages
upgrades = 0
security_upgrades = 0
for pkg in cache.packages:
    candidate = depcache.get_candidate_ver(pkg)
    current = pkg.current_ver

    # skip packages not marked as upgraded/installed
    if not (depcache.marked_install(pkg) or depcache.marked_upgrade(pkg)):
        continue

    # increment the upgrade counter
    upgrades += 1

    # keep another count for security upgrades
    if is_security_upgrade(candidate):
        security_upgrades += 1

    # double check for security upgrades masked by another package
    for version in pkg.version_list:
        if (current and apt_pkg.version_compare(version.ver_str, current.ver_str) <= 0):
            continue
        if is_security_upgrade(version):
            security_upgrades += 1
            break

print "%d updates to install." % upgrades
print "%d are security updates." % security_upgrades
print "" # leave a trailing blank line
EOF

cat <<EOF >> 90-footer
#!/bin/sh
#
#    90-footer - write the admin's footer to the MOTD
#    Copyright (c) 2013 Nick Charlton
#    Copyright (c) 2009-2010 Canonical Ltd.
#
#    Authors: Nick Charlton <hello@nickcharlton.net>
#             Dustin Kirkland <kirkland@canonical.com>
#
#    This program is free software; you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation; either version 2 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License along
#    with this program; if not, write to the Free Software Foundation, Inc.,
#    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

[ -f /etc/motd.tail ] && cat /etc/motd.tail || true
EOF