June 07, 2008
Older: Available For Hire
Newer: Programmers Should Give Up More Often
What's the IP For?
In the spirit of clogging, here is a short diddy for you. I am constantly looking up ip’s for domains. I don’t know why and can’t present you with a use case but I do it a lot. What I typically do is fire up terminal, ping the domain and then copy the ip to my clipboard. Granted this doesn’t take long, but for the guy who aliases script/console to sc, it seems like ages. Also, I never quite select the text properly and I have to hit ctrl-c to kill ping, etc, etc.
Today I whipped together a tiny ruby script to do all the work for me. Now for some code.
#!/usr/bin/env ruby
require 'resolv'
unless ARGV.size == 1
puts "-> Usage: ipfor example.com"
exit
end
# only works on mac
def paste(str)
%x[echo "#{str}" | pbcopy]
puts "-> Pasted #{str} to your clipboard"
end
begin
paste(Resolv.getaddress(ARGV.first))
rescue Resolv::ResolvError
puts "-> Could not resolve '#{ARGV.first}'"
endI put this in ~/bin, named it ipfor (without.rb) and chmod u+x ipfor to make it executable. Once you’ve done that (and assuming you have ~/bin in your PATH), you can do the following on the command line:
~ $ ipfor -> Usage: ipfor example.com ~ $ ipfor railstips.org -> Pasted 208.113.156.68 to your clipboard ~ $ ipfor railstips -> Could not resolve 'railstips'
Yep, it automatically resolves the ip and pipes it into the mac command that pastes text to the clipboard. So like I said, nothing special but it saves me a few seconds here and there. Also, it was fun to see what the different ways to get an IP using ruby were. At first I was just using %x with ping and parsing the output. Then it hit me that I probably wasn’t the first person needing to resolve domains, so I looked through ruby core and found the resolv library.
8 Comments
Jun 07, 2008
Only slightly related, but if you were using ping to do name resolution, check out “dig”. On OSX it’s installable through ports.
It’s a nice tool to know when you are faced with DNS problems, as it’ll tell you TTL and what nameserver it’s getting answers from, and can be used to query about other records like MX and NS.
Jun 07, 2008
nslookup rubyonrails.org
:)
It doesn’t do the copying and isn’t clean enough to pipe on a pbcopy, but is easier than both dig and ping.
Jun 07, 2008
I’m fond of:
host example.com
Particularly since it shows the CNAME relationships (often interesting) and round-robin IPs.
You could get round-robin IPs out of your script code like this:
def ips_for(host) Resolv::DNS.open do |dns| ress = dns.getresources(host, Resolv::DNS::Resource::IN::A) ress.map { |r| r.address.to_s } end end puts ips_for('example.com').join(' ')Jun 07, 2008
Seconding Adam,
hostis awesome. Check out the man page for more goodies likehost -t mx foo.comJun 08, 2008
I know this is ruby/rails stuff but one can easily pull this off by a simple bash function →
function ipfor(){
IP=`host -ta $1 | head -n1 | awk ‘{print $4}’`
if [ `echo “${IP}.” | grep -E “([0-9]{1,3}\.){4}”` ]
then
echo $IP | pbcopy
echo “→ Pasted $IP to your clipboard”
else
echo “→ Could not resolve $1”
fi
}
Just throw it in .profile and you have a new shell function ;)
Cheers!
Jun 08, 2008
That’s a lot of work for:
dig tanga.com +short | pbcopy
Jun 08, 2008
If there is anyone who would like this to work in Linux (particularly, Debian-based systems), do this:
Jun 08, 2008
Sweet. Awesome tips everyone. Most of the things mentioned I’m not that familiar with so I appreciate the comments.
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