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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 3 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; }

Know a better way?

If you can do better, submit your command here.

What others think

This is odd. Today is the 22nd, and I posted it on the 18th, yet it's still not visible. WTF?

Comment by unixmonkey365 276 weeks and 2 days ago

Your point of view

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