shell script email format / condition reworking

Question

context: im working on a redhat radius Server and i have a Shell script which sends me an email every time an unauthorized user tries to Access the Network (e.g: Invalid User: Switch: Switch xxx | Port: xx | Mac-Adress: xxxxxxxxxxxxxx)

my script Looks like the following:

#!/bin/bash



while :

do

if [ ! -e myFile ] ; then

grep Invalid radius.log > myFile

mailx -E -s Radius-Invalid-User myuser@email.com < myFile

else

comm -23 <(grep Trigger-Word radius.log) myFile| mailx -E -s Radius-Invalid-User myuser@mail.com

grep Trigger-Word radius.log > myFile

fi

sleep 1

done

This script works fine and does exactly what it should do, but the Output in the mail is just the line from the logfile and pretty bad to read:

Mon Jan 22 09:38:24 2018 : Auth: (18) Invalid user: [000000000] (from client client-id port 15 cli xx-xx-xx-xx-xx-xx) switchname Port: |15|

so i have to reparse it. And there the trouble starts.

I tried to rework it so that the mail output is:

|-------------------------------------------------------------|

  Switch: 

|-------------------------------------------------------------|

  Port-Nr: 

|-------------------------------------------------------------|

  MAC-Address: 

|-------------------------------------------------------------|

i thought the script part should look like the following:

(
echo "|-------------------------------------------------------------|"
echo " "
echo "  Switch: `awk 'END {print $19}' myFile`"
echo " "
echo "|-------------------------------------------------------------|"
echo " "
echo "  Port-Nr: `awk 'END {print $21}' myFile`"
echo " "
echo "|-------------------------------------------------------------|"
echo " "
echo "  MAC-Address: `awk 'END {print $11}' myFile`"
echo " "
echo "|-------------------------------------------------------------|"
) | mailx -E -s Radius myuser@mail.com

the Problem here is, that the mail is not empty anymore, so the -E from the mailx command does not help + it does not check anymore if this message was sent already. Because it is an endless loop it sends permanent mails with the "blank form".

Can someone help me how to fix it that the script does the exact same Thing the first script does, but with sending the mail in a proper format.

if you need an more information please let me know Big thanks in advance

Answer 1

#!/bin/bash
 
l=radius.log                                            # logfile, all logs
m=myFile
 
_sendMail(){                                            # send mail if not empty
  local f msg="$(</dev/stdin)"                          # mail contents
  if [[ -n "$msg" ]]; then                              # if contents not empty
    while read -r -a f || [[ -n "${f[20]}" ]]; do       # read line by line
      [[ -z "${f[20]}" ]] && continue                   # ignore mal-formatted log
      echo "|-------------------------------------------------------------|"
      echo "  Switch: ${f[18]}"
      echo "|-------------------------------------------------------------|"
      echo "  Port-Nr: ${f[20]}"
      echo "|-------------------------------------------------------------|"
      echo "  MAC-Address: ${f[10]}"
      echo "|-------------------------------------------------------------|"
    done <<<"$msg" | (echo "-----> $1"; cat)            # fake sending for test
    #done <<<"$msg" | mailx -E -s "$1" myuser@email.com # real sending, $1 = subject
  fi
}
 
while :; do                                             # endless loop
  if [[ ! -e "$m" ]]; then
    grep "Invalid user" "$l" >"$m"
    _sendMail "Invalid $l" <"$m"
  else
    n=$(grep "Invalid user" "$l")
    comm -23 <(echo "$n") "$m" | _sendMail "Radius Invalid User"
    echo "$n" >"$m"
  fi
  sleep 1
done

---

To test:

1. Run the bash script

2. From another terminal, continuously add log lines to radius.log, example:

   $ echo 'Auth: (18) Invalid user: [000000000] (from client client-id port 15 cli xx-xx-xx-xx-xx-xx) switchname Port: |15|' >>radius.log

3. The bash script detect the new logs and send mail if that log line contain "Invalid user:".

Outputs:

$ ./report-error.sh 
-----> Radius Invalid User
|-------------------------------------------------------------|
  Switch: switchname
|-------------------------------------------------------------|
  Port-Nr: |23|
|-------------------------------------------------------------|
  MAC-Address: [000000000]
|-------------------------------------------------------------|
-----> Radius Invalid User
|-------------------------------------------------------------|
  Switch: switchname
|-------------------------------------------------------------|
  Port-Nr: |33|
|-------------------------------------------------------------|
  MAC-Address: [000000000]
|-------------------------------------------------------------|
-----> Radius Invalid User
|-------------------------------------------------------------|
  Switch: switchname
|-------------------------------------------------------------|
  Port-Nr: |33|
|-------------------------------------------------------------|
  MAC-Address: [000000000]
|-------------------------------------------------------------|
|-------------------------------------------------------------|
  Switch: switchname
|-------------------------------------------------------------|
  Port-Nr: |33|
|-------------------------------------------------------------|
  MAC-Address: [000000000]
|-------------------------------------------------------------|

Answer 2

i solved it by myself :

#!/bin/bash



while :

do

        if [ ! -e RadiusLogInvalidarchive ] ; then

                grep Invalid radius.log > RadiusLogInvalidArchive

                mailx -E -s Radius-Invalid-User myuser@mail.com < RadiusLogInvalidArchive

        else


comm -2 -3 <(grep Invalid radius.log) RadiusLogInvalidArchive > testFile


        if [ -s testFile ] ; then


                awk ' BEGIN {
                print "|-------------------------------------------------Invalid User-----------------------------------------------------|"
                print " "
                print " >> Port-NR <<         >>  Switch <<             >> MAC-Address << "
                print " "}
                {print "                 ", $22, "                   ", $19, "                  ", $11}' testFile | mailx -E -s Radius-Test myuser@mail.com

        fi


grep Invalid radius.log > RadiusLogInvalidArchive

                if [ -f testFile ] ; then

                        rm testFile

                fi
        fi

sleep 1

done