A Technical I.T./DevOps Blog
Problem scenario
You have uninstalled and reinstalled Thunderbird. You used CCleaner to eliminate traces of a previous configuration of Thunderbird. You want to have no vestiges of the old data and older email account. How do you get clean start with Thunderbird (like an installation on a new workstation that has never had it)?
Solution
1. Open Thunderbird
2. Right click on an email username on the left (e.g.,
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Problem scenario
You are using a Red Hat derivative of Linux. You want to install Erlang (e.g., for development, or to use RabbitMQ or Chef Server). What do you do?
Solution
Run this script with the “sudo” command (e.g., sudo bash /tmp/erlang.sh)
# Written by www.continualintegration.com
#/bin/bash
# We suggest calling this script erlang.sh and placing this file in /tmp/
yum -y install ncurses-devel gtk2-devel
curl -Ls https://github.com/wxWidgets/wxWidgets/releases/download/v3.0.4/wxWidgets-3.0.4.tar.bz2 /tmp/wxWidgets-3.0.4.tar.bz2
cp /tmp/wxWidgets-3.0.4.tar.bz2 /bin/
cd /bin/
bzip2 /tmp/wxWidgets-3.0.4.tar.bz2
tar -xf wxWidgets-3.0.4.tar
cd wxWidgets-3.0.4
./configure
cd /bin/
git clone https://github.com/erlang/otp.git
cd otp
./otp_build autoconf
./configure
echo “This next portion may take 15 minutes”
date /tmp/datetime.txt
yum -y groupinstall “Development Tools”
make
make install
ln -s /usr/local/lib/erlang/bin/erl /usr/bin/erl
ln -s /usr/local/bin/erlc /usr/bin/erlc
yum -y install python3*
ln -s /etc/alternatives/python3 /usr/bin/python
echo “Script run completed.”
echo ” ”
echo “Many errors above may be ignorable”
echo “try the ‘erl’ command with no quotes to see if Erlang was installed”
echo ‘If you get to a carrot prompt, …
Continue reading “How Do You Install Erlang on CentOS/RHEL/Fedora?”
Problem scenario
Using PowerShell, how do you retrieve all files that are greater than 20 MB?
Solution
Run a command like this:
Get-ChildItem C:\ -recurse | where-object {$_.length -gt 20971520} | Sort-Object length | ft fullname, length -auto
This was adapted from this external website.
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Continue reading “How Do You Find Files on the C: Drive That Are Greater than 20 MB?”
Problem scenario
You know that sessions of a JavaScript can be exploited in today’s world. This category of vulnerability is related to imperfections in authentication and is listed as the #2 biggest web application security risk as of June of 2020 (according to OWASP). What are some techniques to stop such attacks from happening when designing a website that uses JavaScript?
Possible Solution #1
Ensure cookie information is passed using connections that leverage HTTPS (as paraphrased from page 23 of Node.js Security by Liran Tal).
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Problem scenario
You want to install OWASP ZAP (aka Open Web Application Security Project’s Zed Attack Proxy). You want to test it out. How do you do this on Linux?
Solution
Note: It is advisable to only install ZAP on OSes that have JREs that have up-to-date patches with regular maintenance. If you need assistance installing the JRE, see this posting.
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Continue reading “How Do You Install and Configure OWASP ZAP?”
Problem scenario
You try to run an aws ssm command. But you get an error about a connection timing out. What should you do?
Solution
Find the EC-2 server’s VPC and subnet. Go to VPC in the AWS console. Go to the Subnet section. Find the Route Table associated with the subnet for the EC-2 server. Make sure that the “Destination” field accommodates the IP address of the ssm.us-west1.amazonaws.com hostname.
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Problem scenario
When you have logged into hotmail, outlook.com, or live.com, and you do not see the option to “Log Off”. How do you log out?
Solution
Go to this URL: https://login.live.com/logout.srf
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Problem scenario
You have a sizable cryptocurrency position. You are concerned that if you lose it, you will not be able to get it back. What should you do?
Solution
This is not legal advice.
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Continue reading “How Do You Insure Your Bitcoin/Cryptocurrency Holdings?”
Background
Facebook’s engineering culture during its earlier days of rapid growth was “move fast and break things.” But the Harvard Business Review says that this era is over.
Problem scenario
You are concerned about recommended practices and “best practices.” You want to be productive and leave no security gaps in your systems that you design/install or allow bugs in your code.
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Continue reading “What are Recommended Practices vs. “Best Practices”?”
Problem scenario
You are trying to run a hadoop command (to kick off a mapreduce job). But you get this error:
“Exception in thread “main” java.nio.file.AccessDeniedException: /home/jdoe/./mapper.py”
What should you do?
Solution (short version)
Change to a directory where the user can write files to. Retry the command.
Solution (long version)
Create a directory that is owned by the user and the group associated with the user that is running this command.
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