Date: Thu, 14 Sep 2017 20:55:00 -0400 From: Ernie Luzar <luzar722@gmail.com> To: "freebsd-questions@freebsd.org" <freebsd-questions@freebsd.org> Subject: Help scripting dns lookup using awk Message-ID: <59BB24E4.6060908@gmail.com>
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The following sh script works, but runs very slow.
host_in="$1"
host_out="$2"
host_error="$3"
truncate -s 0 $host_out
truncate -s 0 $host_error
# Make the input file read a line at a time, not a field at a time.
IFS=$'\n'
set -f
for line in `cat $host_in`; do
domain_name=`echo -n $line | cut -w -f 1`
host $domain_name > /dev/null
if [ $? -ne 0 ]; then
echo "$domain_name" >> $host_error
else
echo "$domain_name" >> $host_out
fi
done
The follow script uses awk trying to do the same thing.
host_in="$1"
host_out="$2"
host_error="$3"
truncate -s 0 $host_out
truncate -s 0 $host_error
cat $host_in | awk '
{ system(host $1)
rc_status = system($0)
if (rc_status != 0)
print $1 > $host_error
else
print $1 > $host_out
}'
# command line exec command.
>hosts2void-dns_lookup.awk /tmp/aw.hosts \
/root/good.dns /root/bad.dns
# This is the output.
sh: medrx.sensis.com.au: not found
sh: medrx.sensis.com.au: not found
awk: illegal field $(), name "host_error"
input record number 1, file
source line number 5
I see 2 problems with my awk code.
1. The text output of the host command results is going
the console screen. In the sh version I kill the output
using > /dev/null How would I to do something like that in awk.
2. I get that doing print $1 > $host_error is not allowed.
What is the correct way to pass script variables to awk?
Now I am wondering if there is a simpler way to do dns lookup
in awk?
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