check_ubuntu_updates

#!/bin/bash
# Checks Ubuntu updates including security

# Exit codes
OK=0
WARNING=1
CRITICAL=2
UNKNOWN=3

exitcode=$UNKNOWN
codetext=("Ok" "Warning" "Critical" "Unknown")

# Usage help
usage() {

  text="
USAGE: ${0} [-c <number> | -w <number>]
-c : return critical if the number of security updates exceeds the limit
-w : return warning instead
"
  echo "$text"

  exit $exitcode
}

# check for command line arguments
while getopts "w:c:h" option
do
  case "$option" in
    c) critical=$OPTARG;;
    w) warning=$OPTARG;;
    h) usage;;
    *) usage;;
  esac
done

APTCHECK=$(/usr/lib/update-notifier/apt-check 2>&1)
UPDATES=$(echo $APTCHECK | cut -d ';' -f 1)
SECURITY=$(echo $APTCHECK | cut -d ';' -f 2)

if [[ -z $UPDATES || -z $SECURITY ]]
then
  echo "No recognizable output."
  exit $UNKNOWN
fi

exitcode=$OK

message="$UPDATES updates ($SECURITY security)|'All updates'=$UPDATES 'Security updates'=$SECURITY"

# threshold checks
[[ (! -z $warning) && ($SECURITY -ge $warning) ]] && exitcode=$WARNING
[[ (! -z $critical) && ($SECURITY -ge $critical) ]] && exitcode=$CRITICAL

echo "Ubuntu updates ${codetext[$exitcode]} - $message"
exit $exitcode