My friend today asked me how to convert all spaces in filenames under a specified directory to underscores. Also, at the same time lowercase all of the filenames. Here is a quick script to do what is needed. Let us start with creating some test data in a temp directory:

mkdir temp
cd temp
touch Foo FooO "Foo Bar" "FOO BAaR"
\ls | while read -r FILENAME
do
mv -v "$FILENAME" `echo $FILENAME| tr ' ' '_'| tr '[A-Z]' '[a-z]'`
done

Note:  I intentionally have slash in front of ls (\ls).  \ls means that we want to make sure there is no ls alias overwriting our command. This is needed if your system has alias setup to display ls in a different way instead of default listing.  mv -v shows us the filenames being renamed as your script goes through the whole dir.  Your output should be like:

`Foo' -> `foo'
`FOO BAaR' -> …

Server monitoring is a big part of running a solid web site.  As an admin, you must know what is going on your server.  One of the tools most Linux/Unix admins are used to is called “top”.  “top” by itself is a very powerful tool.  Here is a quick guide on how to read output from top:  introduction to load averages under top.  It just makes sense that somebody went and created httptop to monitor http traffic.

Install perl modules:

install Term::ReadKey
install File::Tail
install Time::HiRes

Now copy paste the script below and save it in a location and set +x attribute on it so you can execute it.  On my …

As you may know mysql fulltext search is not highly scalable.  One of the options to get around this scalability limitation, which I prefer, is to use Sphinx.  You can use Sphinx with out having to alter your mysql installation.  But, if you would like to use from within mysql and not have to worry about how to pass data between Sphinx and MySQL, you can enable sphinxse (sphinx storage engine).  It is not included with mysql by default so you will have to compile it yourself.

Here are the instructions on how to get sphinxse compiled with your mysql installation on CentOS x64.  I am sure same instructions will work for other flavors but I have not tested it.  I will be compiling the most current version of sphinx (0.9.8) with most current stable version of mysql (5.0.51b) at the time of the writing.  Let’s get the appropriate …

Red Hat releases Spacewalk. It is described as: “the upstream community project from which the Red Hat Network Satellite product is derived“. Congratulations to all whom have worked on it, especially my friends who tired endlessly over it in the past.

Red Hat, is sticking true to its promise, of open sourcing everything they make. Best of all, they recognise Fedora (they always did, since say, Fedora Core 2 or 3), CentOS (a direct “competitor”/rebuild of RHEL), and Scientific Linux (I know of a certain university’s sysadmin who will be blessing Spacewalk, as her life will now be a lot easier).

There have been a few blogs about it… Matt Asay asks about a community (Red Hat traditionally wasn’t good at this, but with Fedora, I believe they’ve learned, and I’m happy …

Installing MySQL Proxy On CentOS 5 (FINAL) x86_64

This tutorial explains how you can install MySQL Proxy on a CentOS 5 (x86_64) system. MySQL Proxy is a simple program that sits between your client and MySQL server(s) that can monitor, analyze or transform their communication. Its flexibility allows for unlimited uses; common ones include: load balancing; failover; query analysis; query filtering and modification; and many more.

Installing MySQL Proxy On CentOS 5 (FINAL) x86_64

This tutorial explains how you can install MySQL Proxy on a CentOS 5 (x86_64) system. MySQL Proxy is a simple program that sits between your client and MySQL server(s) that can monitor, analyze or transform their communication. Its flexibility allows for unlimited uses; common ones include: load balancing; failover; query analysis; query filtering and modification; and many more.

Most of the users who work with distributions such as: centos, fedora, redhat, etc use yum as a package update/installer. Most of them know how to do “yum update [packagename]” (to update all or [certain packages]) or they do “yum install packagename” to install certain package(s). But yum can do so much more. Here are some options you may find useful:

Following command will search for the string you specified. Generally this will give you all of the packages which has specified string in title or description. Most of the time you will have to look through a lot of output to find what you are looking for.

yum search string

Probably one of the most important options for yum is provides/whatprovides. If you know what command you need, you can find out what package you have to install in order to have that command available to you.

yum provides (or whatprovides) command

Quick 'n' Easy LAMP Server For CentOS/RHEL

This tutorial shows a quick way of installing a LAMP server (Linux + Apache + MySQL + PHP/Perl together commonly known as LAMP Server.) on CentOS and RHEL server systems.

Update: Karanbir says “Just one thing to keep in mind is that we dont want too many people using it from the Testing repository - we only need enough feedback to move it from testing to stable ( and to be honest, there are already 8 people who have said yes it works - so move to stable should happen within the next 24 - 48 hrs ). Once the package is in stable, users on CentOS4 and 5 wont need to do anything more than just ‘yum install maatkit’ and it will install for them.”

At least one person (Karanbir Singh) is working to get Maatkit into the CentOS repositories, and I believe there might be movement towards RHEL also. From an email to the Maatkit discussion list a little while ago,

I am in the process of getting maatkit into the CentOS-Extras …

I honestly do not know why somebody would want to export each record from a table in to its’ own files in a csv format. I am sure people have their own reasons. But since I got request from couple people, I figure I would post a solution here. Same script can be used to dump the whole table in to one csv file as well, with little tweaking. I will start with creating database with a table. I then insert three rows with test data into the table just to show three separate files creation.

mysql> CREATE DATABASE testdump;
mysql> USE testdump
mysql> CREATE TABLE `testtable` (
`id` TINYINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY ,
`testfield` VARCHAR( 15 ) NOT NULL ,
`testfield2` VARCHAR( 15 ) NOT NULL
) ENGINE = innodb COMMENT = 'test table for dumping each row to file';
mysql> INSERT INTO `testtable` values ('','test1','test2'),('','test3','test4'),('','test5','test6'); …