check_udp_port

#result=`sudo /usr/bin/nmap -sU -p $port -P0 $host`
result=`sudo /usr/bin/nmap -sU -p $port -P0 $host| grep ^${port}/.*`
f_result=`echo $result Nmap done`
p_result=`echo $f_result | awk '{print $1" "$2" "$3}'`

Good plugin, been using for a while.
Today I upgraded Debian from 9.9 to 10 and this plugin stopped working.
The problem is probably in grep change
line 50:
f_result=`echo $result | egrep -o "${port}/udp [a-zA-Z0-9_-| ]+Nmap done"`

plugin output:
grep: Invalid range end
CRITICAL:

Does anyone know how to fix this issue?
I am no expert at regex

Thanks

Hello,
I have to give permissions to execute all the users the nmap command
chmod u+s /usr/bin/nmap

And I change exit value at the end, to UNKNOWN state because is confused CRITICAL state.

echo "UNKNOWN: $p_result ------"
exit ${STATE_UNKNOWN}

I changed the following line to avoid problems with services containing "open" in the name, e.g.: openvpn

if [ `echo $f_result | egrep -c 'udp open'` -gt 0 ]; then

Thanks for this helpful tool.
For some nmap-versions (e.g. nmap 5.21 on opensuse 11.4) you will have to remove an extra line with the MAC-address after the port line to get a valid result string:

PORT STATE SERVICE
177/udp open xdmcp
MAC Address: 00:30:48:11:22:33 (Supermicro Computer)

Nmap done: 1 IP address (1 host up) scanned in 0.09 seconds



As not being familiar with extended regular expressions I extended the nmap statement:

result=`/usr/bin/nmap -sU -p $port -P0 $host |grep -v MAC`

This works but feel free to find the respective expression for f_result.

I had to escape the dash in the egrep pattern (using GNU egrep 2.14), but after that it worked great!

f_result=`echo $result | egrep -o "${port}/udp [a-zA-Z0-9_-| ]+Nmap done"`