[SOLVED] How can I set an exit option in shell script

rockie321 · 07-27-2012, 03:38 AM

Hi
I am trying to collect OS details from multiple servers

Have a file /tmp/a which contains 10 server names

and I process it via for loop to do a df command on all these servers. I want the script to skip a particular server and proceed to the next one if its not able to connect to it or the password provided is wrong. Can I code a line in the script to do that ?

If I press a Ctrl +C, the script will terminate. I don't want that, but to move to the next server name in /tmp/a.

Can this be done ?

for i in `/tmp/a`
do
ssh $i "df -h" >>\output
done

pan64 · 07-27-2012, 03:53 AM

you need to check the trap settings of the shell,

divyashree · 07-27-2012, 06:10 AM

Quote:

Originally Posted by rockie321

Hi
I am trying to collect OS details from multiple servers

Have a file /tmp/a which contains 10 server names

and I process it via for loop to do a df command on all these servers. I want the script to skip a particular server and proceed to the next one if its not able to connect to it or the password provided is wrong. Can I code a line in the script to do that ?

If I press a Ctrl +C, the script will terminate. I don't want that, but to move to the next server name in /tmp/a.

Can this be done ?

for i in `/tmp/a`
do
ssh $i "df -h" >>\output
done

You can add a condition before doing ssh:

Code:

for IP in $(cat /tmp/a)
do
  ping -c 2 $IP
  if [ $? -eq 0 ]
  then
    echo $IP can be connected
    ssh $IP "df -h" >>/output
  else
    echo $IP cant be connected
  fi
done

rockie321 · 07-27-2012, 08:30 AM

Quote:

Originally Posted by divyashree

You can add a condition before doing ssh:

Code:

for IP in $(cat /tmp/a)
do
  ping -c 2 $IP
  if [ $? -eq 0 ]
  then
    echo $IP can be connected
    ssh $IP "df -h" >>/output
  else
    echo $IP cant be connected
  fi
done

Thanks Divyashree. That would solve the "not able to connect issue". Is there something that I can do for exiting back to the script/for loop when I provide a wrong password

cbtshare · 07-27-2012, 08:24 PM

It would be best not to use passwords, if you just want a script to log in and check the disk space or whats mounted.Just use ssh keys.

divyashree · 07-27-2012, 11:33 PM

yes, cbtshare is correct. You should not use passwords in script. Instead you can setup ssh for password less login using PKI .

1 - Generate public/private key pair on the local server ( use - ssh-keygen )
2 - Distribute the public key it to all the servers you want to monitor( Use - ssh-copy-id )

rockie321 · 07-28-2012, 10:41 AM

I agree with both of you. But is there a way by which I can interact with a for loop ?

etech3 · 07-28-2012, 08:13 PM

You may want to tweak a few things.

Code:

ping -qc2 $IP

The -q is for quiet output to the screen.

Code:

echo  $IP Can be connected >>/OUTPUTFILE

will put a header with the IP address of each server from the /temp/a list into the output file.

Like so:

Code:

192.168.0.XXX Can be connected

Then continue on with the info:

Code:

Filesystem            Size  Used Avail Use% Mounted on

just my

Kenhelm · 07-28-2012, 10:34 PM

An example of interacting with a for loop using trap:-

Code:

#!/bin/bash
trap 'continue' SIGINT

echo 'Press CTRL-C to end each loop immediately.'
for n in 1 2 3 4 5; do
  echo "loop $n: sleeping for 10 seconds....."
  sleep 10
done

rockie321 · 08-05-2012, 11:04 AM

Thanks All.

I was able to get what was requested.

Code:

trap 'continue' INT
echo 'Press CTRL-C to end this loop immediately.'
for server in `cat file`
do
ping -qc2 $server
if [ $? -eq 0 ]
then
echo $server is pingable
echo $server >>/output
ssh $server "df -h" >>\output
else
echo $server is not pingable
fi
done