UNIX for Dummies Questions & Answers

Hi.....
Thanks for this wonderful forum....

My request:

I have toatally 5 unix servers in which many applications are working

I need to set a trap to identify 0 byte files if any are created proactively.

For example:

Code:

find /apps/fresco/ -mtime 1 -size 0c –print >> zerobytefile.log

This command will find zero byte file for last 1 day (no need to check entire directory every day and this is for /apps/fresco folder which will cover all the interfaces and will apply for all my servers) then filter this log file for any data and if any data is present then raise a trap.

First off: welcome to the forum and i hope you enjoy the ride. Please do us (and yourself) a favour and use as little text markup as possible. For any code, terminal output or similar data use "CODE"-tags, which let stand out yor text nicely. I have taken the liberty and replaced this in the quoted text above. Compare yourself. Thanks for your consideration.

To your problem: you alread constructed a command to identify such files. Instead of the ">>" operator you used you should use ">" to create this file anew every day. Establish passwordless login through ssh for some user (likely root, but any other user with sufficient rights will do) at each of the target machines. Put this command into a loop on any system, like this (only a sketch):

Code:

# cat list_of_hosts_to_monitor
hostA
hostB
hostC
hostD

# cat mymonitoring.sh
#! /bin/ksh

typeset fHosts="/path/to/list_of_hosts_to_monitor"
typeset fOut="/path/to/output/dir"
typeset chUser="root"          # or something else
typeset chHost=""

while read chHost ; do
     ssh -o 'BatchMode = yes' "${chUser}@${chHost}" "find /apps/fresco/ -mtime 1 -size 0c -print" > "${fOut}/${chHost}.log"
done < "${fHosts}"

exit 0

This gives you a file for each host (named like the hostname+".log") locally (in the directory $fOut points to) which you can examine separately.

Then set up a cron job to run this script daily.

I hope this helps.

bakunin

Thank you so much. I'm new to this forum I haven't expected such a quick response. I will learn quickly to post messages in better way.

'Establish passwordless' is not possible for me hence I have changed my mind to write a script for all 5 servers separately.

If I use that command mentioned earlier, some zero byte files are coming which is actually not in my scope. I want took all the paths which is not in our scope and now I want a script which should connect a single IP through ssh and gives me an output of zero byte file excluding the paths not in our scope which has zero byte.

I am not sure why this is a bettwer way to do this. "passwordless" means: create a secure-key with ssh-keygen on the system you want to run the script from. The resulting file is usually located in /your/homedir/.ssh in a file named (if you use the default RSA encryption) id_rsa.pub. Open/create the fle /home/of/user/.ssh/authorized_keys on the remote machine you want to connect to and append the content of the local file id_rsa.pub there. Now the user from the system you generated the key at is allowed to connect as the user where you stored the keyfile at without password. The user is not identified by the password but by the key you transmitted.

Actually the script i gave you does exactly this: it connects to a single machine, issues the command, saves its outcome, then goes on to do the same to the next machine on the list. To cut some paths from finds scope there are two ways: use the "-prune" option to prune away some paths you are not interested in or use grep -v to cut out from the output what doesn't peak your interest.

You might want to search this forum for "find" and "prune" with the "advanced search" feature to find out how this is done. It is the preferable way to do it.

I hope this helps.

bakunin

Moderator's Comments:

addendum: i just noticed that this has landed in the wrong forum. I move this over to "Unix for Dummies"