Simple nmap scanner / differ

autonmap.sh

#!/usr/local/bin/bash

SCAN_TARGETS="x.x.x.x/28 x.x.x.x/27 x.x.x.x"
EMAIL_RECIPIENTS="email@example.com.com"
WEB_URL="https://tools.example.com/scans/scan-$DATE.xml"

RUN_DIRECTORY="/usr/local/scans/data/"
NMAP="/usr/local/bin/nmap"
NDIFF="/usr/local/bin/ndiff"


DATE=`date +%FT%T%z`
echo "`date` - AutoNMAP beginning run. "

cd $RUN_DIRECTORY || exit 2
echo "`date` - Executing nmap, please wait. This may take a while."
$NMAP --open -T4 -PN -sV $SCAN_TARGETS -n -oX scan-$DATE.xml --stylesheet "nmap.xsl" > /dev/null
echo "`date` - Process completed with exit code $?"

if [ -e scan-latest.xml ]
then
    echo "`date` - Running ndiff..."
    DIFF=`$NDIFF scan-latest.xml scan-$DATE.xml 2>&1`

    echo "`date` - Checking ndiff output"
    # there are always two lines of difference, the run header that has the time/date in; ignore that
    if [ `echo "$DIFF" | wc -l` -gt 2 ]
    then
            echo "`date` - Differences detected."
            echo -e "AutoNMAP ***detected changes*** in network footprint. \n\nTargets scanned: ${SCAN_TARGETS}\n\nDiff output:\n$DIFF\n\nFull report available at $WEB_URL" | mail -s "$(echo -e "AutoNMAP network scan results\nImportance: High")" $EMAIL_RECIPIENTS
    else
            echo "`date`- No differences detected."
            echo -e "AutoNMAP did not detect changes in network footprint. \n\nTargets scanned: ${SCAN_TARGETS}\n\nDiff output:\n$DIFF\n\nFull report available at $WEB_URL" | mail -s "$(echo -e "AutoNMAP network scan results\nImportance: Low")" $EMAIL_RECIPIENTS
    fi

else
    echo "`date` - There is no latest scan (scan-latest.xml). Cannot diff this run; will do next run."
fi

ln -sf scan-$DATE.xml scan-latest.xml

echo "`date` - AutoNMAP is complete."
exit 0