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
PHPMyAdmin :: Existing configuration file (./config.inc.php) is not readable
The Problem I have just installed LAMP on my CentOS machine and while trying to access phpMyadmin thorugh cPanel, get below error: Existing configuration file (./config.inc.php) is not readable. The Solution The above error is due to the misconfiguration of permissions of the phpMyAdmin configuration file - /usr/local/cpanel/base/3rdparty/phpMyAdmin. Follow the steps outlined below in order to resolve the issue: 1. Login to the server with root user. 2. View current the permissions … [Read more...] about PHPMyAdmin :: Existing configuration file (./config.inc.php) is not readable
cp: omitting directory – error while copying a directory in Linux
The Problem When we are trying to copy a directory to other location, we get below error: $ cp /data01 /data02 cp: omitting directory '/data01' $ The Solution The error above is a common mistake done by Linux newbies while copying a directory to other locations without using the recursive copy option in the 'cp' command. In order to avoid this error use the "-r" or the "-a" option in the copy command. From the man page of 'cp' command: # man cp -R, -r, --recursive copy … [Read more...] about cp: omitting directory – error while copying a directory in Linux
ORA-00257:Archiver Error, Connect Internal Only Until Freed
The Problem Users cannot connect to the database : 0RA-00257:archiver error, connect internal only until freed ORA-16014:log 2 sequence# 231 not archived, no available destinations ORA-00312:online log 2 thread 1:'/[path]/redo02.log' The Solution The most probable cause for this error is that the flashback recovery area must have gone full. SQL> archive log list; Database log mode Archive Mode Automatic archival Enabled Archive Destination USE_DB_RECOVERY_FILE_DEST Oldest online … [Read more...] about ORA-00257:Archiver Error, Connect Internal Only Until Freed
How to Use user-defined Functions in awk
User-Defined Functions You can create user-defined functions in a awk script file using the func or function keywords. Placement in the file is not important; the function definition can occur anywhere in the awk script. The function can take arguments (local to the function only) or use any existing variable. The syntax of a function definition is: func function_name ([optional_arg] . . .) { statements } or function function_name ([optional_arg] . . .) { statements } The … [Read more...] about How to Use user-defined Functions in awk
Using Loops (while, for) in awk scripts
The awk programming language contains many of the programming concepts that are used in shell scripting. Conditionals, such as the if statement and loops, such as the following can also be used in awk programming. The while loop The do while loop The for loop The if Statement The if statement can have two branches: an if branch and an else branch. If the condition is true, the if branch is executed; if the condition is false, the else branch is executed. if (condition) { … [Read more...] about Using Loops (while, for) in awk scripts