A Technical I.T./DevOps Blog
Goal: You want to issue a command (e.g., an export command) that has a password in it. But you do not want anyone looking over your shoulder to see it. You do not want the password to be visible in the history of the shell.
Solution: Type this ‘read -s foobar’
Then press enter. The cursor will go to the next line. Type in the password. The characters will not echo to the screen.
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Continue reading “How Do You Assign a Password to a Variable In Linux Without Making It Visible?”
Problem scenario: When trying to use PowerShell to download a file, get you this error ‘Error calling “DownloadFile” with “2” argument(s): “An Exception occurred during a WebClient request.”‘
Solution: Make sure you have ample space on the disk and make sure the destination folder exists. A typo in the path or if the folder not existing could cause this error. Insufficient disk space could also cause the problem.
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Continue reading “How to Troubleshoot PowerShell Downloading a File From the Internet”
Updated 1/5/18
THESE DIRECTIONS ARE OUTDATED. They are here as a reference for legacy purposes only. For directions on how to install Hadoop on a RedHat or CentOS server, see this article.
Problem scenario
You want to install an open source version on a RedHat derivative distribution of Linux in a public cloud. How do you do this?
Solution
These directions will allow you install Hadoop on a RedHat derivative (e.g.,
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These “directions” to install Suricata on SUSE Linux include a script and how to run it. The script was designed to install Suricata 3.1dev on an AWS instance of SUSE 12 SP1. This script was based on these here. This script requires that your AWS SUSE Linux server is in a security group that has access to the Internet. The script takes approximately five minutes to run. But bandwidth and resources on your instance may vary.
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Continue reading “How to Install Suricata on an AWS Instance of SUSE Linux”
Problem scenario: On Ubuntu, after installing Hadoop, when you enter the command ‘/usr/local/hadoop/bin/hadoop namenode -format’ and you get this error:
“Error: JAVA_HOME is not set and could not be found.”
Solution: Verify Java is installed (‘java -version’). If it is not installed, you can use ‘apt-get install -y default-jre’.
Next, go to hadoop-env.sh. Find the export JAVA_HOME stanza. Change the ‘${JAVA_HOME}’ value to ‘/usr’ with no quotes.
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Continue reading “How To Get Hadoop Installed on Ubuntu When There Is a Java Error”
Problem scenario
When you log into Ubuntu, you see a message like this:
8 packages can be updated.
5 updates are security updates.
You run this: sudo apt-get -y update
This completes. But next time you log in, you see the same message about 8 packages can be updated. What do you do?
Solution
Run this command: sudo apt-get -y upgrade
If you are looking for deploying Hadoop to Ubuntu,
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Updated on 11/28/17
Problem scenario
You want to install Suricata on Ubuntu Linux. How do you do this?
Solution
These directions to install Suricata include a script and how to run it. The optional script in 2.c was based on these here. The optional script in 2.c script requires that your AWS Ubuntu Linux server is in a security group that has access to the Internet.
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Continue reading “How to Install Suricata on an AWS Instance of Ubuntu Linux”
Problem Scenario: You want to use Ant to invoke your customized build.xml file. But when you run it, you get “
Target “build.xml” does not exist in the project …”
Solution: Call ant with no other variables. Do not use “ant build.xml”. Use “ant” by itself.
Miscellaneous: Most CentOS/RedHat repositories will have Ant available. As root, the command “yum install ant” should get it installed.
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Continue reading “How to Use Ant (when You Receive an Error about build.xml Not Existing)”
Question 1: What are the packages that must be installed on a CentOS server to have it serve as the Kerberos server?
Answer 1: These three packages: krb5-server krb5-libs krb5-auth-dialog
Question 2: What are the packages that must be installed on a CentOS server to have it serve as the Kerberos client?
Answer 2: These three packages:
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Continue reading “What Are the Minimum Packages Necessary for Kerberos on CentOS?”
Problem scenario: When using Jenkins, PsExec never seems to work when called as a batch command in a .bat file or PowerShell script. Jenkins logs an error about the PsExec command not being found.
Solution / workaround: PsExec seems to never work if called by a PowerShell script or a batch script via Jenkins. The only exception seems to be if a Scheduled Task calls a .bat file or PowerShell script that uses PsExec.
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