Shell script to email about nslookup failure

[Tharshini]

I'm currently writing a shell script to do nslookup on a list of servers which could be obtained from listener file. Could anyone please help me how to send an email notification in case nslookup failed for a server?

[James R. Ferguson]

Hi:

cat ./nsfailure
#!/usr/bin/sh
HOST=$1
RSLT=$(nslookup $1 | sed -ne "/can.t find/p")
[ -z "${RSLT}" ] || mailx -s "nslookup failed: ${RSLT}" root < /dev/null
exit

# ./nsfailure host_or_IP

Regards!

...JRF...

[James R. Ferguson]

Hi (again):

Oops, we need to capture STDERR, so:

# cat ./nsfailure
#!/usr/bin/sh
HOST=$1
RSLT=$(nslookup $1 2>&1 | sed -ne "/can.t find/p")
[ -z "${RSLT}" ] || mailx -s "nslookup failed: ${RSLT}" root < /dev/null
exit

# ./nsfailure host_or_IP

Regards!

...JRF...

[Tharshini]

Hi James,

Thanks so much for your help. I'm modifying the script at the moment and it will be ready to go by tomorrow.

I will let you know about the result.

Thanks so much again!

Best Regards,
Tharshini

[James R. Ferguson]

Hi (again):

Since you are new to this forum, welcome!

If/when you are satisfied with the answers you have received, please read:

http://forums.itrc.hp.com/service/forums/helptips.do?#28

Regards!

...JRF...

[Tharshini]

Hi James,

When I tried to run the script, it did not accept and gave this error continuously.
`RSLT=$' unexpected.

This is the script:
#!/bin/sh

cat /disk1r1/app/oracle/product/10.2.0/db_1/network/admin/sqlnet.ora | cut -d= -f3 | grep -v 10 | grep -v 192 | grep -v ")" | sed 's/\(.*\)./\1/' >> output.txt

log="/apps/dba/bin/output.txt"; export log
rm log

for HOSTNAME in `more log`
do
RSLT=$(nslookup $HOSTNAME 2>&1 | sed -ne "/can.t find/p")
[ -z "${RSLT}" ] || mailx -s "nslookup failed: ${RSLT}" root < /dev/null
done

exit

Thanks for helping me out.

Best Regards,
Tharshini

[James R. Ferguson]

Hi:

> When I tried to run the script, it did not accept and gave this error continuously.
`RSLT=$' unexpected.

What shell are you running on what HP-UX release? '/bin/sh' should point to '/usr/bin/sh' which should be the POSIX shell.

The notation:

RSLT=$(nslookup ${HOST} 2>&1 | sed -ne '/can.t find/p')

...is a better (POSIX) form of the archaic back-ticks:

RSLT=`(nslookup ${HOST} 2>&1 | sed -ne '/can.t find/p'`

See if the back-tick syntax fixes your problem.

Regards!

...JRF...

[Dennis Handly]

>it did not accept and gave this error continuously
>for HOSTNAME in `more log`

You shouldn't be using more(1) here, that's for interactive use. Instead use:
for HOSTNAME in $(< log); do

>JRF: See if the back-tick syntax fixes your problem.

You left in a "(":
RSLT=`nslookup ${HOST} 2>&1 | sed -ne '/can.t find/p'`

[James R. Ferguson]

Hi (again):

> Dennis: You shouldn't be using more(1) here, that's for interactive use. Instead use:
for HOSTNAME in $(< log); do

If Tharshini is running a non-POSIX shell, I think that this too will be an issue. I would suggest the alternative:

for HOSTNANE in `cat log`; do

> Dennis > JRF: You left in a "(":
RSLT=`nslookup ${HOST} 2>&1 | sed -ne '/can.t find/p'`

Yes indeed I did. Thanks for catching that.

Regards!

...JRF...

[Dennis Handly]

>JRF: If Tharshini is running a non-POSIX shell,

But Tharshini said: This is the script:
#!/bin/sh