The Problem If the MySQL password contains a dollar sign character '$', PHP is unable to connect and issues an error like: Access denied for user 'username'@'hostname' (using password: YES) Connections via other clients work correctly. The Solution PHP interprets dollar signs inside of double quotes as starting a variable name, which will be expanded. This expansion will change the password sent to MySQL. There are 3 ways to avoid this problem: Escape the character with a … [Read more...] about “Access denied for user ‘username’@’hostname’ (using password: YES)” – Error while connecting MySQL with PHP
How to Restrict MySQL User Creation with Blank Password
Question: How can we not allow user creation with a blank password in MySQL? Using a blank password for a user is always a no go. In order to restrict user creation with blank password follow the steps given below: Before MySQL 5.6 In case of MySQL version below 5.6, this can not be achieved completely. But there are settings that can be used to come closer to our objective. Set the below SQL mode on the MySQL instance: SET SQL_MODE = NO_AUTO_CREATE_USER Using NO_AUTO_CREATE_USER … [Read more...] about How to Restrict MySQL User Creation with Blank Password
Beginners Guide to MySQL Data Types
Data Types: Overview In MySQL, the available data types can be grouped into four major categories: Numeric: Numeric values Binary: Binary data strings Character: Text strings Temporal: Time and date values Within each category, there are numerous specific data types that use varying amounts of memory and disk space, and thus have varying effects on performance. Choosing the best data type for the column has a rather small effect on performance in an individual record, but as the … [Read more...] about Beginners Guide to MySQL Data Types
What is the purpose of utmp, wtmp and btmp files in Linux
In a Linux system, everything is logged in a log file under the directory called /var/log. This directory contains logs related to different services and applications. In this directory we have some files such as utmp, wtmp and btmp. Unlike the system log files and the authentication log files, all of these files are binary files. So, we can't use our normal text tools, such as less or grep, to read them or extract information from them. Instead, we'll use some special tools that can read these … [Read more...] about What is the purpose of utmp, wtmp and btmp files in Linux
“expect” script to provide password to mysql_config_editor
Question: How to provide a password to mysql_config_editor without exposing it on the command line and without having to be present to type it? Use an expect script. For example: #!/usr/bin/env expect spawn mysql_config_editor set --skip-warn --login-path=client --user=root --password expect "Enter password: " send "$env(my_password)\r" expect eof The password can be stored in whatever location is considered secure enough for the operation that is accessible by the script. … [Read more...] about “expect” script to provide password to mysql_config_editor
How to (Correctly) Change the UID and GID of a user/group in Linux
Changing the UID and GID of a user might seem a trivial task to most of the system admins. But it's not so trivial and it involves a lot more changes in the backend. In this post, we have outlined the exact steps to change the UID and GID of a user "user01". Username: user01 Group: group01 Existing UID: 800 Existing GID: 700 New UID: 900 New GID: 600 Pre-requisites 1. Make sure the user for which UID and GID is to be changed is currently not having any active process running in the … [Read more...] about How to (Correctly) Change the UID and GID of a user/group in Linux