A Technical I.T./DevOps Blog
Problem scenario
You want to test the $# built-in Linux variable. Every time you use it, it seems to return “0.” How do you see the number of arguments in the most recent command?
Solution
Create a bash script with the following lines “echo… to fi”:
echo “This script helps you learn about built-in variables in Linux.”
if [ $# -eq 1 ]
…
Continue reading “How Do You Use the $# Builtin Linux Variable?”
Problem scenario
You think the Apache web server is running. You can see the web page from a web browser or your coworkers tell you that it is running. You are not 100% sure however. You want to see the Linux pid (process ID) for Apache web service that is running. You run this:
ps -ef | grep httpd
You do not see any services running.
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Problem scenario
You have a Linux server with the command prompt but no GUI. A separate server hosts GitLab. How do you configure the first character-based server to use GitLab?
Solution
This assumes that you have deployed GitLab; if you need directions for this, see this posting. This assumes that you have created a project in GitLab. If you need directions for this, see this
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Problem scenario
In an Ubuntu-based Docker container, how do you install MariaDB and start the MariaDB service?
Solution
Run these commands:
sudo apt-get -y update
sudo apt-get -y install vim
sudo apt-get install mariadb-server
sudo service mysql start
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Question
What and when was the first reference to cloud automation operations?
Answer
The cloud (e.g., the SaaS model or public cloud offerings) allow for new types of automation in computing. Before electricity existed, pneumatic and hydraulic automations were among the oldest automations in history. The only man-made clouds back then were smoke or steam clouds.
Homer’s Iliad refers to cloud automation. This appears to the be earliest use of such an idea (a gate),
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Continue reading “What and when Was The First Reference to Cloud Automation Operations?”
Question
In the Context of Nginx, What Is the Difference between the default.conf and nginx.conf Files?
Answer
For general Nginx purposes, the nginx.conf file specifies the location of the Nginx logs and the names of the log files themselves.
For general Nginx purposes, the default.conf handles many more configuration items than nginx.conf. The default.conf file will allow you to configure a non-standard port (other than port 80) and specifies if Nginx will act as a load balancer or a web server.
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Problem scenario
You are trying to run a bash/shell script but you get an error message that is difficult to troubleshoot. It looks something like this:
myscript.sh: line 4: syntax error near unexpected token `curl’
myscript.sh: line 4: `curl ‘http://10.10.0.1’ ‘
You thoroughly analyzed the line of the script that is called out in the error. What is the root cause?
Solution
Did you define a function in the script?
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Problem scenario
You have deployed the LAPP stack. You want a basic and meaningful message to be presented to a user of the web application after a SQL command has been run. Currently a user can click on buttons to run SQL commands behind the scenes. Messages that are returned to the user may be meaningless like “Resource id #4” or “Resource id #5.” You want to augment the functionality so at least a rudimentary message (with some meaning) is returned to the user.
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Problem scenario
You are trying to install Snort on Ubuntu. You have installed hwloc (because you know the command hwloc-info works). But when you try to run a configure script (e.g., configure_cmake.sh), you get this error:
“– Could NOT find PkgConfig (missing: PKG_CONFIG_EXECUTABLE)
CMake Error at cmake/FindHWLOC.cmake:6 (message):
ERROR! hwloc library not found.
Get it from https://www.open-mpi.org/projects/hwloc/
Call Stack (most recent call first):
…
Continue reading “How Do You Deal with An “hwloc library not found” Error?”
Updated 1/4/19
Question
You have heard of Azure’s Serverless Function Apps. What are they and what do they do?
Answer
A Serverless Function App is a PaaS solution. As of 1/4/19 they support .NET or JavaScript code as if the code was run on a Windows environment. They will eventually support Java/Linux.
You can run a program without a server using Azure. It could potentially be accessible on the web or through other connectors to different Azure servers.
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