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Functions

a function to find the fastest free DNS server

Terminal - a function to find the fastest free DNS server
timeDNS () { { for x in "${local_DNS}" "208.67.222.222" "208.67.220.220" "198.153.192.1" "198.153.194.1" "156.154.70.1" "156.154.71.1" "8.8.8.8" "8.8.4.4"; do ({ echo -n "$x "; dig @"$x" "$*"|grep Query ; }|sponge &) done ; } | sort -n -k5 ; }
2011-08-18 01:11:53
Functions: dig echo grep sort
1
a function to find the fastest free DNS server

Evoke from the command like as:

timeDNS commandlinefu.com

.

This isn't too terribly practical, but it is a good code example of using subshells to run the queries in parallel and the use of an "anonymous function" (a/k/a "inline group") to group i/o.

.

I'm assuming you have already defined your local DNS cache as ${local_DNS}, (here, it's 192.168.0.1).

.

You do need to install `moreutils` to get `sponge`.

.

If you're willing to wait, a slower version w/o sponge, (and w/o sorting), is this:

.

DNS () { for x in "192.168.0.1" "208.67.222.222" "208.67.220.220" "198.153.192.1" "198.153.194.1" "156.154.70.1" "156.154.71.1" "8.8.8.8" "8.8.4.4"; do (echo -n "$x "; dig @"$x" "$*"|grep Query) ; done ; }

Alternatives

There are 2 alternatives - vote for the best!

Terminal - Alternatives
timeDNS() { parallel -j0 --tag dig @{} "$*" ::: 208.67.222.222 208.67.220.220 198.153.192.1 198.153.194.1 156.154.70.1 156.154.71.1 8.8.8.8 8.8.4.4 | grep Query | sort -nk5; }
curl -s http://public-dns.info/nameserver/br.csv| cut -d, -f1 | xargs -i timeout 1 ping -c1 -w 1 {} | grep time | sed -u "s/.* from \([^:]*\).*time=\([^ ]*\).*/\2\t\1/g" | sort -n | head -n1
2017-02-02 12:00:38
User: glaudiston
1

http://public-dns.info gives a list of online dns servers. you need to change the country in url (br in this url) with your country code. this command need some time to ping all IP in list.

Know a better way?

If you can do better, submit your command here.

What others think

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Comment by jamessusan104 8 weeks and 4 days ago

Your point of view

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