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The grub bootloader is particularly useful, especially when upgrading and testing new kernels. I recently found a way to modifiy the default boot config to make it useful when you wish to remotely upgrade a kernel and boot into it once only without being at the console to change the default back.

Java is a programming language and computing platform first released by Sun Microsystems in 1995. It is the underlying technology that powers state-of-the-art programs including utilities, games, and business applications. Java runs on more than 850 million personal computers worldwide, and on billions of devices worldwide, including mobile and TV devices.

The stub_status module provides the ability to get some stats from nginx...

active connections -- number of all open connections including connections to backends

server accepts handled requests -- nginx accepted connections, handled connections (no one was closed just it was accepted), and handles requests (requests per connection = handles requests / handled connections)

reading -- nginx reads request header

writing -- nginx reads request body, processes request, or writes response to a client

waiting -- keep-alive connections, actually it is (active - reading + writing)

Centrify Express is a comprehensive suite of free Active Directory-based integration solutions for authentication, single sign-on, remote access, file-sharing, monitoring The #1 Choice for Active Directory Integration and cloud security for cross-platform systems. It is the quickest and most proven solution for integrating UNIX, Linux and Mac systems with Windows, and delivers more functionality and more to upgrade to when compared to other free offerings.

Whenever sendmail has to deliver mails to other hosts which cannot be reached at that time, the messages are kept in the queue. Although the other hosts could be reached again and you want to tell sendmail to flush the mail queue, the command

sendmail -q -v

does not really try to reconnect to these hosts and still assumes that the connection timed out. The reason is that the hoststatus is cached, per default for a period of 30 minutes. Using

sendmail -OTimeout.hoststatus=0m -q -v

you can re-run the mail queue and force sendmail to reconnect to the hosts.

Finding a good solution for sharing files between Linux users is a nightmare.

If using a unique UID is not a problem, it's the most simple solution. All clients access files with the same UID. This way you cannot know who does what, and users cannot fine tune access rights.

Dec to hex converter (or a dec to hex convertor) is a tool used to convert numbers expressed in the decimal format into hexadecimal or short hex format. Dec to hex conversion is common when working with web sites and graphics...

The 'edac' kernel module goal is to detect and report errors that occur
within the computer system running under linux.

MongoDB wasn’t designed in a lab. We built MongoDB from our own experiences building large scale, high availability, robust systems. We didn’t start from scratch, we really tried to figure out what was broken, and tackle that. So the way I think about MongoDB is that if you take MySql, and change the data model from relational to document based, you get a lot of great features: embedded docs for speed, manageability, agile development with schema-less databases, easier horizontal scalability because joins aren’t as important.

Sometimes I want to FTP a file from one machine to another. Usually, I can do the transfer interactively, but every so often, I would like to have a shell script do the file transfer. This task has eluded me in the past, but I finally figured it out. I've not seen this particular trick documented in the past, so I submit it for your approval...