Featured »

March 2, 2022 – 2:00 pm

Books have been written on the subject of awk and sed. Here’s a small sample of commands I put together over the years that are useful for everyday system administration tasks. Most of these tasks …

Read the full story »
Networking

Unix and Linux network configuration. Multiple network interfaces. Bridged NICs. High-availability network configurations.

Applications

Reviews of latest Unix and Linux software. Helpful tips for application support admins. Automating application support.

Data

Disk partitioning, filesystems, directories, and files. Volume management, logical volumes, HA filesystems. Backups and disaster recovery.

Monitoring

Distributed server monitoring. Server performance and capacity planning. Monitoring applications, network status and user activity.

Commands & Shells

Cool Unix shell commands and options. Command-line tools and application. Things every Unix sysadmin needs to know.

Home » Archive by Month

Article Archive for June 2009

Wget and User-Agent Header

June 29, 2009 – 12:41 pm
computer_security_it_privacy_0003

As you may already know, Wget is a popular (particularly in the Unix world) command-line downloader and Web crawler application. You can read more about Wget in one of my earlier posts on the subject. …

Numeric File Permissions in Unix

June 27, 2009 – 7:50 pm
shell_001

Suppose you are working with a Web server and your task is to make sure that no files or directories have permissions “777”. It would be easy to just recursively change permissions for all files …

Duplicating WordPress Installation

June 25, 2009 – 2:51 pm
wordpress_logo

Whenever you upgrade your WordPress installation or do development work, it is always a good idea to be working on a copy of your main site and not on the real thing. Copying WordPress installation …

Restart Apache, MySQL When Low on Memory

June 25, 2009 – 4:27 am
logo_mysql

Heavy traffic, hungry SQL queries, leaky applications will eventually leave your server low on memory. Apache will go on a hunt for swap space and MySQL will start freezing in thoughtful contemplation. Your hard drives …

MySQL Global Search and Replace Script

June 25, 2009 – 3:53 am
logo_mysql

A day will eventually come when your need to find and replace a string of text in your database. You don’t know which row, or which column, or which table. Heck, you may not even …

Passing MySQL Commands from Shell Script

June 25, 2009 – 3:30 am
mysql_0002

Running MySQL commands from a shell script is a relatively simple task that has a lot of people baffled. Some say its too complicated and suggest using PHP or Perl, others claim doing so is …

WordPress Directory Listing Risk

June 11, 2009 – 11:36 pm
wordpress_0004

A large number of WordPress directories do not have an index file. This is particularly dangerous in case of the plugins directory. If your server allows directory listings, a potential attacker may see which plugins …