Category Archives: Software

How to check in Bash script if a Docker volume does not exist

Posted on December 17, 2021 by Siddharth Jain

Sometimes you may want to check if a Docker volume exists or not in a Bash script: To check existence of a Docker volume we can use the docker volume ls command with the name option but there are several … Continue reading →

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Access Denied for User ‘root’@’localhost’ (using password: YES)

Posted on December 16, 2021 by Siddharth Jain

In this post I describe a lesser known reason you may run into Access Denied for User ‘root’@’localhost’ (using password: YES) error when trying to login to MySQL. The setup is as follows: you are running MySQL inside a Docker … Continue reading →

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Bash script to upgrade a Docker container

Posted on December 2, 2021 by Siddharth Jain

Problem: We have an application that has a single instance and runs in a Docker container and further uses a swarm network. We want to write a bash script using which we can deploy new version of the application. The … Continue reading →

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Extract comments in PDF file

Posted on November 3, 2021 by Siddharth Jain

Here are step by step instructions on how to extract comments in a PDF file. The steps to do it using Adobe PRO are documented here. This posts describes how to do it if you do not have Adobe PRO. … Continue reading →

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Debugging cron jobs

Posted on September 7, 2021 by Siddharth Jain

Open /etc/rsyslog.conf (RHEL 7.x) and check for following line: The path in previous step gives the filename to which cronjob runs will be logged. Open that file. Whenever a cronjob is executed, an entry is logged into this file. Example … Continue reading →

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invalid literal for int() with base 10

Posted on June 16, 2021 by Siddharth Jain

UPDATE: It turns out none of this works. I ran into the same error with latest VS Code and ms-python extension. The fix was to stick a breakpoint before the input command to prevent VS Code from taking conda activate … Continue reading →

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Databases 101

Posted on June 9, 2021 by Siddharth Jain

Structured Data Unstructured Data Semi-structured data – the best way to think of structured data is data that can be queried through SQL – Structured Query Language– this means data has a schema and is made up of typed primitives … Continue reading →

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Understanding dates and time in MySQL

Posted on June 8, 2021 by Siddharth Jain

TL;DR: Set your server timezone and connection time zone to both ‘+00:00’ and use datetime instead of timestamp when you want to store dates outside the range supported by timestamp (‘1970-01-01 00:00:01.000000’ to ‘2038-01-19 03:14:07.999999′). Do’s when using datetime: Add a suffix … Continue reading →

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MySQL Foreign Keys

Posted on June 2, 2021 by Siddharth Jain

I used to think that the foreign key column has to be unique [ref] but that is not the case. Consider the tables below where we have a parent -> child -> grandchild relationship. A competition has teams and a … Continue reading →

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Dealing with annoying Azure Devops Permissions

Posted on May 28, 2021 by Siddharth Jain

Like many other of its products Azure Devops is over-engineered and a pain to use. Unfortunately you might have to use it in your organization. One of the biggest problems I have run into with it is when it will … Continue reading →

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