topic Re: Shell Script for file monitoring in Operating System - Linux

Shell Script for file monitoring

Sreejith Kumar — Thu, 20 Sep 2007 02:00:47 GMT

Hi,

I want to monitor a file and whenever it gets changed we should receive email notification regarding the same.

For example: i want to monitor the file name "/etc/passwd". Once it is found that
the file is got changed then it should send email notification to Admin.

Can any one suggest shell script for this ?

Thanks,
Sreejith

Re: Shell Script for file monitoring

Oviwan — Thu, 20 Sep 2007 02:18:23 GMT

Hey

check the time of the file with one of those commands:

ls -l file (modification time)
ls -lc file (change time)
ls -lu file (access time)

then compare it with the results of the check before, e.g. you check it each hour...

if its's not the same time, send a mail.

hope this helps

Regards

Re: Shell Script for file monitoring

Ernesto Cappello — Thu, 20 Sep 2007 02:53:41 GMT

Hi Sreejith, this is my script:

#!/bin/sh

FILE_DATE=`/bin/ls -al /etc/passwd | /bin/awk '{print $6 $7}'`

DATE=`/bin/date | awk '{print $2 $3}'`

if [ "$FILE_DATE" -eq "$DATE" ]
then
mailx -s "Check File (`hostname`)" name.surname@company.com < /etc/passwd
fi

Best regards.
Ernesto

Re: Shell Script for file monitoring

Srimalik — Thu, 20 Sep 2007 03:53:44 GMT

#!/usr/bin/sh
CURR=`ls -l /etc/passwd`
while true
do
PREV=CURR;
sleep 1; # check the file every second
CURR=`ls -l /etc/passwd`
if [ PREV != CURR]
then
//Send a mail (read previous reply)
fi
done
############
I have not tested it, Please look for any shell specific errors.

-Sri

Re: Shell Script for file monitoring

AwadheshPandey — Thu, 20 Sep 2007 05:47:37 GMT

Hello Sreejith,

Here it comes,

create a backup password file file to some where as per your choice I assume that you have /etc/paswd.old, then schedule script below in crontab as per your requirment.

#!/bin/ksh

typeset -i old_time=`ls -lc /etc/passwd.old |awk '{print $8}'|awk -F: '{print $1$2}'`
typeset -i new_time=`ls -lc /etc/passwd |awk '{print $8}'|awk -F: '{print $1$2}'`

echo "Old Modication Time:" $old_time > tmpfile
echo "New Modification Time:" $new_time >> tmpfile

if (( $old_time != $new_time ));

then

mailx -s "password tmpfile modified" email.id@xyz.com < tmpfile
cp -p /etc/passwd /etc/passwd.old

fi

Regards,

Awadhesh

Re: Shell Script for file monitoring

spex — Thu, 20 Sep 2007 07:56:06 GMT

Hello,

The best solution is to use Tripwire (part of Internet Express), as it is intended for this kind of thing. Set up a "tripwire -m c" cronjob to run as often as you like.

Or you could create a script such as the following:

#!/usr/bin/sh
echo "Comparing /etc/passwd.1 to /etc/passwd"
diff /etc/passwd.1 /etc/passwd
echo "Moving /etc/passwd.1 to /etc/passwd.2"
cp /etc/passwd.1 /etc/passwd.2
echo "Copying /etc/passwd to /etc/passwd.1"
cp /etc/passwd /etc/passwd.1
exit 0

'diff' looks at the contents of a file, not its attributes, which may or may not work for your purposes. Schedule it to run as often as you like.

PCS

Re: Shell Script for file monitoring

James R. Ferguson — Thu, 20 Sep 2007 08:05:52 GMT

Hi:

I presume that you are using a shadow password file since otherwise normal users changing their password would update '/etc/passwd'. That saiid, however, I'm still puzzled by your question if it is specific to the aforementioned file. If the permissions and ownership on '/etc/passwd' are correctly restricted, only 'root' can modify it. Thus, why would you want to montior potential changes?

Regards!

...JRF...

Re: Shell Script for file monitoring

Tim Nelson — Thu, 20 Sep 2007 09:44:31 GMT

A thought that may/may not be worth the hassle.

If eventually you would like to do this to support audit and monitor many other files HP IDS9000 does this on a system wide bases as well as other things.

It is free and may be worth looking into.

Re: Shell Script for file monitoring

Sreejith Kumar — Thu, 20 Sep 2007 23:24:37 GMT

Fine Awdesh its working