KrazyWorks

Getting Epoch Time on Solaris 10 and Older

September 8, 2014 – 3:57 pm

You can get the epoch time on Solaris 11 and Linux simply by running the date command:

Quick Setup of Salt on CentOS/RHEL

August 21, 2014 – 2:58 pm

Just some quick notes on installing and configuring Salt master server and minions to run remote commands for various sysamdin needs.

Searching Files for Text Strings

July 28, 2014 – 4:22 pm

In the past, I’ve posted a couple of versions of this script in Bash and Korn shell. Here’s a much-expanded and improved Bash version. The script will take your input and look for files containing …

Recovering Deleted /bin on CentOS

June 25, 2014 – 1:54 pm

So, as the saying goes, shit happens and the other day I accidentally deleted /boot on a CentOS 6 box. I have NetBackup running on the system, so this would not have been a problem …

Disable Formatting When Pasting into Outlook

June 24, 2014 – 9:25 pm

By default, Outlook will preserve source text formatting during copy/paste operations. At times this can be very annoying, especially when composing emails of technical nature. There’s a good chance your email will end up looking …

Installing GoAccess on CentOS/RHEL

June 24, 2014 – 11:02 am

GoAccess is a simple but useful “top”-like CLI utility giving you a quick overview of the Apache access_log entries.

What To Do When Windows Ignores SD Card

June 22, 2014 – 11:17 pm

Here’s a common scenario: you insert or swap and SD card in your laptop and… nothing happens. Sometimes Windows decides to ignore the SD card for reasons unknown (well, the true reason is it’s Windows). …

Permanently Ban IP with Fail2Ban

June 9, 2014 – 12:12 am

If you’re not familiar with Fail2Ban: it’s a log analysis tool that detects failed login attempts for your SSH, FTP, etc services and uses IPTools firewall to temporarily drop connection requests from the offending IP addresses. …

NTP Client Configuration on CentOS

May 15, 2014 – 8:31 pm

Just some quick note on configuring NTP client on CentOS/RHEL/Fedora and forcing time update. Just got tired of having to remember these steps every time I run into NTP.

Searching Log Files

April 18, 2014 – 4:40 pm

This is a quick example of finding the first and last occurrence of an event in the log file. This can be useful for determining the service outage window and for general troubleshooting. In the example below I am looking at the PostFix maillog file, trying to figure out the duration of the problem I’ve been having with one of the mail relay servers.

Looking for Recently Changed Files

April 3, 2014 – 2:55 am

Locating most recently-modified files in the current directory is easy: ls -alt | head. However, searching a directory structure for recent changes may prove a little more challenging. The most common approach is to use …

Installing CentOS 6.x From USB

January 16, 2014 – 12:23 am

If at all possible, don’t do it. Find a blank DVD-RW and burn the ISO file. Most current Linux distros can be easily put on a USB stick using freely-available utilities and installed without a hassle. CentOS is not one of them. It would appear, CentOS was designed specifically to make installation from a USB stick a professional challenge for a seasoned sysadmin.

Matching Installed RPMs on Two Systems

January 6, 2014 – 10:02 pm

The basic problem is this: you have server “A” with a bunch of packages -let’s say PHP-related stuff – installed you need for you application. You need to get the same application working on server “B”, which is not an exact copy of server “A” and is missing some of the packages.

Searching Large Database Tables

December 9, 2013 – 9:19 pm

Recently I ran into a little problem: I needed to make a simple Web UI allowing users to search a database table containing a copy of the Postfix maillog for quarantined mail addressed to them. …

WordPress Remove Extra Line Breaks

December 2, 2013 – 3:09 pm

Frequently, imported posts or posts created by auto-blogging plugins will create unnecessary tabs, newlines, and line breaks. This has a negative impact on readability and aesthetics of your site. If you cannot address the problem …

MySQL mysqlhotcopy Script

December 2, 2013 – 1:30 pm

Here’s a simple script to automate mysqlhotcopy runs from cron to backup multiple MySQL databases. The script loops through the list of databases and kicks off an instance of mysqlhotcopy in the background for each one. Really, …

Monday Rant: HP’s Web Site Fail

November 18, 2013 – 8:21 pm

Every time I come across a link leading to HP’s angry garden salad of a Web site, I feel as if I stepped in chewing gum. Unfortunately for me, being a sysadmin means I have …

Dynamic Variables in BASH

October 10, 2013 – 9:32 am

Assigning variables is easy if you know how many you have and what they are called. The value of a variable can be, well, variable. But the names and number of variables need to be …

VMware vCenter Converter Standalone Notes

October 9, 2013 – 11:28 am

The vCenter Standalone Converter is a handy app you can run on your Windows or Linux PC to to P2V a remote server. As convenient as the Converter is, there are a few gotchas that …

Free Rescue CDs for Windows

October 5, 2013 – 11:32 am

This is just a quick summary of the more popular rescue CDs out there. All of these are Unix-based bootable ISOs. Some are available as self-burning EXE files, which may be useful if you don’t …

Linux Man Pages (man1)

October 1, 2013 – 3:03 pm

The current version of manual pages for the most common Linux commands and options. Just for your online convenience.

My Script Won’t Run from Cron!

September 27, 2013 – 10:36 am

This is a fairly common issue with running scripts from root cron: the script works perfectly when ran manually from command line, but fails in unexpected ways when running automatically from root cron.

Commands & Shells »

Plundering Facebook Photo Albums

Let’s imagine you need to download all the photos in a Facebook photo album. It can be a public album, a friend’s, or even your own. Sure, you can do this manually, but you probably …

Scraping a Web Page in Bash

Just a scripting exercise because I need to do something important, but I am procrastinating. The idea is simple: grab some URL with text containing somewhat structured data and convert it into a spreadsheet. I …

Processing Videos with ffmpeg and Lightroom

On occasion I wondered how to apply advanced photo filters to my lackluster GoPro and drone videos. You know, not the basic exposure/contrast/saturation or the cheesy special effects you find in video editors, but something …

Searching Twitter

Here are just a few hopefully useful tips for searching Twitter to get more relevant results and buy cheap twitter followers.

Scraping a Web Page in Bash

Generating Random Text Files for Testing

Sometimes you need dummy folder structures populated with random data for testing your various scripts and processes – backups, file transfers, encryption, compression, etc. Every time I need something like this, I end up writing …

Finding Cron Jobs

Cron is an indispensable tool for system administration. The difficulties in working with cron in a large environment stem from its decentralized nature. Cron jobs multiply like rabbits, and keeping track of them is not …

Understanding Memory Utilization in Linux

This is a depressing – and all-too-common – scenario: a user runs the free command and opens a support case because he sees zero “free” memory on the server.

Validating HTTPS Cache Peers for Squid

I have a squid proxy server that uses a long list of authenticated cache peers in a round-robin configuration. The process looks something like this:

Verifying SNMP Connectivity on Multiple Hosts

I needed to check if SNMP was accessible on whatever live servers that existed in a particular subnet. Here’s a quick script to do this.

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