A Technical I.T./DevOps Blog
Problem scenario
You want to use a Java Virtual Machine language on a CentOS/RHEL/Fedora server. You want to test out the language too. What should you do?
Prerequisites
Install Groovy; this command should work (assuming your server is configured to work with a yum repository with groovy): sudo yum -y install groovy
# If your yum repositories do not have Groovy, see this posting.
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Continue reading “How Do You Run a Groovy Program on a Red Hat Derivative Linux Server?”
Problem scenario
You have no desktop GUI and a limited ability to install new applications other than the Java compiler. You are not be allowed to install a SQL command line client such as sqlconnect or a utility such as tnsping. What should you do to test the credentials, server name and port number to ensure they work to allow access to an Oracle database?
Solution
The overview is to use a Java program with the code provided below.
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Problem scenario
You get an error such as this on a Linux server:
“Caused by: java.lang.AbstractMethodError: Method oracle/jdbc/driver/OraclePrepreadStatementWrapper.setBinaryStream (IL java/io/InputStream;)V is abstract at oracle.jdbc.driver.OraclePreparedStatementWrapper.setBinaryStream (OraclePreparedStatementWrapper.java)”
What should you do?
Possible Solution #1
If you are doing Java coding, have you imported the packages needed for the line of Java code that is throwing this error?
Possible Solution #2
If you are using JBoss,
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Problem scenario
You are trying to debug a Python program that uses shell (or Bash) commands. The shell or Bash commands work when they are called with Python’s subprocess.check_output. They do not work when called directly from the Linux command prompt. What is wrong?
Possible solutions
Normally I.T. professionals can get the Linux (Bash or shell) commands to work without as many moving parts. In some instances the Python script that executes the Bash commands seem to help the reliability of the commands.
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Problem scenario
You want to use a Java Virtual Machine language on an Ubuntu Linux server. You want to test out the language too. What should you do?
Prerequisites
Install Groovy version 1; this command should work: sudo apt-get -y update; sudo apt-get -y install groovy
Procedures
1. Create a file called hello.groovy with the following five lines:
class Example {
static void main(String[] args) {
println(‘Hello World’); …
Continue reading “How Do You Run a Groovy Program on a Debian or Ubuntu Server?”
Problem scenario
Your C program compiles. But you get the error “Segmentation fault.” You expect the value of a variable to be printed. How do you get the value to be printed without this error?
Solution
Does every print function print? If one print function seems to be displaying the “Segmentation fault” error, look closely at the syntax thereof. Here is a line that will produce this error:
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Problem scenario
You have a Python list with n items. You are getting a “IndexError: pop index out of range” error. The order that these lists are being printed (used or displayed) is not what you expect. Your program prints the entire list initially, so you know what to expect. This IndexError and the order of the items being displayed is not what you expect. Here is an example:
print(fun_list)
[‘item1’,
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Continue reading “How Do You Deal with the Python Error “IndexError: pop index out of range”?”
Problem scenario
You are running a Python program with Boto and you get an error like this:
” aws_access_key_id=AKIAJfoobar9999, NameError: name ‘AKIAfoobar9999’ is not defined”
What should you do?
Solution
Put single quotes around the aws_access_key_id value.
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Problem scenario
You want to install Groovy version 2 on Debian or Ubuntu Linux. What do you do?
Solution
Run these two commands:
sudo apt-get -y update
sudo apt-get -y install groovy2
…
Continue reading “How Do You Install Groovy Version 2 on Debian or Ubuntu Linux?”
Problem scenario
You want to use Grunt the automation tool (https://gruntjs.com). How do you install it and get it to work on Linux?
Solution
#1 If you are using CentOS, Red Hat Enterprise Linux, or Fedora, run these two commands:
sudo yum -y install nodejs npm # *
sudo npm install -g grunt
If you are using Debian or Ubuntu Linux,
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