Perform dig on two lists

Question

I need to run a dig on domains and these domains aliases, so the result will be:
IF domain (+ doesn't have an alias) and is using my Name Servers -> then print out
IF both domain and alias are using my Name Servers -> then print out
Everything else no (including when domain is using my Name Servers and alias don't). I have domains stored in MySQL and there's the script I am working on:

for domain in `echo "$QUERY1" | mysql -N -s -u $USER -p$PASS $DBNAME -h$HOST | awk '{print $1}'; do
    lookup=$(dig $domain ns +short)
    if [[ "$lookup" =~ 'XXX' ]]; then
        our=1
        break
    else
        our=0
        break
    fi
done

In this QUERY I am listing everything (both domains and aliases). I can of course create another query to list only aliases or only domains. It would seem that I would need to group together all the aliases of the domain and loop over the domain name + aliases list. If either one not using NS, I would have to set variable that dictates printing the domain. Let me know, what are your ideas and please share the solution, if possible.

Have you considered using `dig` directly for all of this? It has a batch mode, `dig -f filename`, which is probably exactly what you need. You can use e.g. Awk to parse the query results and generate the batch file. — Wildcard, Nov 05 '16 at 02:51
Also, regarding the shell snippet in your question, I highly recommend reading [Why is printf better than echo?](http://unix.stackexchange.com/q/65803/135943) and [Why does my shell script choke on whitespace or other special characters?](http://unix.stackexchange.com/q/131766/135943) — Wildcard, Nov 05 '16 at 02:51

Kusalananda · Accepted Answer · 2017-01-24T20:34:37.047

Consider the following alternative to the script you're working on:

mysql --silent --skip-column-names \
    --user="$USER" --password="$PASSWORD" \
    --host="$HOST" --database="$DBNAME" \
    --execute="$QUERY1" |
awk '{ printf("%s ns +short\n", $1) }' |
if dig -f - | grep -q "XXX"; then
    our=1
else
    our=0
fi

I prefer using the long options in scripts since they are self-documenting.

The query in $QUERY1 can be crafted in such a way that the awk isn't necessary:

SELECT CONCAT(column, " ns +short") FROM ...

I've made dig read its queries from standard input out of the pipe coming from awk and the grep helps us finding XXX in the output.

No messy looping required.

Obviously, it doesn't do what you want to do at the end, only what you do at the moment, but since I don't know too much about DNS lookups I'll leave it at that.

Perform dig on two lists

1 Answers1