A Technical I.T./DevOps Blog
Problem scenario
You are trying to use a USB stick with your Raspberry Pi. But you get errors you receive say things like “operation not permitted” and “target is busy.” You want to create new directories and files on this thumb drive. What do you do?
Solution
1. Remove the USB stick.
2. Insert it. Do not choose the GUI prompt to use File Manager.
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Continue reading “How Do You Get Raspberry Pi to Use a USB Drive?”
Problem scenario
When trying to install Apache Parquet on Ubuntu, you get this error:
“Running python-snappy-0.5.1/setup.py -q bdist_egg –dist-dir /tmp/easy_install-SIHL_T/python-snappy-0.5.1/egg-dist-tmp-O8UnkU
WARNING: ‘.’ not a valid package name; please use only .-separated package names in setup.py
package init file ‘__init__.py’ not found (or not a regular file)
cc1plus: warning: command line option ‘-Wstrict-prototypes’ is valid for C/ObjC but not for C++
snappymodule.cc:31:22: fatal error: snappy-c.h: No such file or directory
compilation terminated.
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Problem scenario
You are trying to run very long, complex Linux commands. There are many case-sensitive flag options and convoluted DNS names. It takes time to hold the left arrow to go to the beginning of the command. Sometimes you want to comment out a line with a “#” at the beginning of the line as you draft these Linux commands.
Solution
Use ctrl-a to get to the first character of the command.
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Continue reading “How Do You Get to the First Character in a Linux Command Prompt?”
Problem scenario
You turn on an HP computer (e.g., a desktop or laptop) and press Esc to go to the Startup Menu. You then press F10 or use the down key and press enter to get to the BIOS menu. When you are there you see the option you need “Update BIOS Using Local Media” is grayed out. You entered administrator-level credentials successfully.
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Problem scenario
You have started some commands then used Ctrl-z while they were still processing. You want to see which jobs have been suspended. You may want to terminate or run the jobs. What do you do?
Solution
Use the builtin Linux command “jobs” like this:
jobs -l
# Sample output may look like this:
[1]- 26830 Stopped
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Continue reading “How Do You Manage (List, Resume or Terminate) Suspended Linux Commands?”
Problem scenario
You want to enable IP version 4 forwarding on an Ubuntu server permanently. How do you do this without rebooting?
Solution
1. Run this command:sudo sysctl -w net.ipv4.ip_forward=1
2. Modify the /etc/sysctl.conf file. Use “sudo vi /etc/sysctl.conf“
Uncomment out this stanza:
net.ipv4.ip_forward=1
3. Save the changes.
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Continue reading “How Do You Enable IP Version 4 Forwarding on an Ubuntu Server?”
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 ]
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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,
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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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