gistfile1.sh

#!/bin/bash
# bash nagios plugin

###
# Variables
###
OK=0
WARNING=1
CRITICAL=2
UNKNOWN=-1
TO_RETURN=${OK}
TO_OUTPUT=''

# Print usage information and exit
print_usage(){
    echo -e "\n" \
    "usage: ./check_uptime -w 20 -c 30 \n" \
    "\n" \
    "-w <days>    warning value\n" \
    "-c <days>    critical value\n" \
    "-h           this help\n" \
    "\n" && exit 1
}

###
# Options
###

# Loop through $@ to find flags
while getopts ":hw:c:" FLAG; do
    case "${FLAG}" in
        w) # Warning value
            WARNING_VALUE="${OPTARG}" ;;
        c) # Critical value
            CRITICAL_VALUE="${OPTARG}" ;;
        h) # Print usage information
            HELP=1;;
        [:?]) # Print usage information
            print_usage;;
    esac
done

###
# Functions
###

log_date(){
    echo $(date +"%b %e %T")
}

error() {
    NOW=$(log_date)
    echo "${NOW}: ERROR: $1"
    exit 1
}

warning() {
    NOW=$(log_date)
    echo "${NOW}: WARNING: $1"
}

info() {
    NOW=$(log_date)
    echo "${NOW}: INFO: $1"
}

# Do something
get_cmd_output(){
    #generate output
    echo `uptime | sed 's/.*up \([0-9]*\) day.*/\1/'` || error "failed to run command"
}

###
# Program execution
###
[ "${HELP}" ] && print_usage

if [ ${WARNING_VALUE} ] && [ ${CRITICAL_VALUE} ]
then
    CMD_OUTPUT=$(get_cmd_output)
else
    print_usage
fi

if [ "${CMD_OUTPUT}" ] && [ ${CMD_OUTPUT} -gt ${CRITICAL_VALUE} ]
then
    TO_RETURN=${CRITICAL}
elif [ "${CMD_OUTPUT}" ] && [ ${CMD_OUTPUT} -gt ${WARNING_VALUE} ]
then
    TO_RETURN=${WARNING}
elif [ "${CMD_OUTPUT}" ] && [ ${CMD_OUTPUT} -gt 0 ]
then
    TO_RETURN=${OK}
else
    TO_RETURN=${UNKNOWN}
fi

if [ $TO_RETURN == ${CRITICAL} ]
then
    TO_OUTPUT="CRITICAL "
elif [ $TO_RETURN == ${WARNING} ]
then
    TO_OUTPUT="WARNING "
elif [ ${TO_RETURN} == ${OK} ]
then
    TO_OUTPUT="OK "
else
    TO_OUTPUT="UNKNOWN "
fi

TO_OUTPUT="${TO_OUTPUT}| uptime=${CMD_OUTPUT};$WARNING_VALUE;$CRITICAL_VALUE"

echo "$TO_OUTPUT";
exit $TO_RETURN;