Brad Lucas

Programming, Clojure and other interests

Get Ip Address Of Ec2 Instance

July 31, 2017

A quick command to figure out what your IP address is.

$ curl checkip.amazonaws.com
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Amazon Linux Ami

July 30, 2017

  • Based on CentOS/Redhat and you can use Redhat/Centos repositories
  • Has better integration and has EC2 management tools pre-installed
  • There may be issues at times due to dependency issues
  • One potential issue is you can't run Amazon Linux outside of EC2
  • Local/developer builds may be on their own RHEL/Centos but there may be slight differences
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Rename Group Of File Extensions In Git

July 29, 2017

For this example, I had a collection of text files with embedded mode lines to setup the mode for org-mode. I wanted to do away with the mode line and rename them from txt files to org files.

Build the GLOB before hand and verify with ls. For example ls *.txt would have the GLOB value in the example replaced with *.txt.

The git mv renames the files.

for i in $(find . -iname "GLOB"); do
    git mv "$i" "$(echo $i | rev | cut -d '.' -f 2- | rev).org";
done
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Upgrade To Java 1.8 On Ec2

July 28, 2017

Update to Java 1.8 on EC2

  • sudo yum install java-1.8.0- sudo yum remove java-1.7.0-openjdk
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Ethereum Get Eth Balance Script

July 27, 2017

The site Etherscan allows you retrieve information on accounts and transactions. There is an interface to the Reposten testnet as well. While doing some work on a project I was monitoring the page to view an account balance and ended up creating a script to do the monitoring programmatically.

The repo listed at the bottom of the page contains the python script which simply parses the page and returns the balance.

The main routine after figuring out which chain the user wants to look at and which account is the get_balance routine. It parses the page and finds the balance in the first table's first row, second cell.

def get_balance(url):
    html = requests.get(url, headers={'User-agent': 'Mozilla/5.0'}).text
    soup = BeautifulSoup(html, "html.parser")
    table = soup.find("table", {"class" : "table"})
    value = table.findAll('td')[1].text.split(' ')[0].strip()
    return value

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