Best of Technical Support
I am using Red Hat 4.2. I would like to give a user who is not root the permission to shut down the system. The man page says, “write the name of the user in the file /etc/shutdown.allow”. Unfortunately, this has no effect, i.e., the user gets the message “must be root” after typing shutdown. —Thomas Okon, okon@math.tu-dresden.de
The only way I know of for any user to correctly shut down a Linux system is to be physically present at the keyboard and press ctrl-alt-del. This key sequence has the effect of running shutdown from init(8). This is the default behavior and all /etc/shutdown.allow does is to restrict ctrl-alt-del even more to specifically named users.
I am using Red Hat 5.0. How can I write a script that compares two directories recursively, one on the localhost, the other on an FTP site, then upload only the newer files to the FTP site? I wish to easily update my web site which is getting quite large and difficult to update manually. —Grim_Sweeper@softhome.net
The good news is the solution is already available. The bad news is that you will have to configure it to fit your needs. I'm talking about the mirror package available at ftp://src.doc.ic.ac.uk/packages/mirror/mirror.tar.gz. This is an excerpt from the man page:
Mirror was written for use by archive maintainers but can be used by anyone wanting to transfer a lot of files via ftp. Regardless of how it is called, mirror always performs the same basic steps. It connects to the remote site, internally builds a directory listing of the local target directory, builds one for the remote directory, compares them, creates any subdirectories required, transfers the appropriate files (setting their time-stamps to match those on the remote site), creates any symbolic links, removes any unnecessary objects and finally drops the connection.
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It's Raspberry Pi month at Linux Journal. Each week in May, Adafruit will be giving away a Pi-related prize to a lucky, randomly drawn LJ reader. Winners will be announced weekly.
Fill out the fields below to enter to win this week's prize-- a Pi Cobbler Breakout Kit for Raspberry Pi.
Congratulations to our winners so far:
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Free Webinar: Hadoop
How to Build an Optimal Hadoop Cluster to Store and Maintain Unlimited Amounts of Data Using Microservers
Realizing the promise of Apache® Hadoop® requires the effective deployment of compute, memory, storage and networking to achieve optimal results. With its flexibility and multitude of options, it is easy to over or under provision the server infrastructure, resulting in poor performance and high TCO. Join us for an in depth, technical discussion with industry experts from leading Hadoop and server companies who will provide insights into the key considerations for designing and deploying an optimal Hadoop cluster.
Some of key questions to be discussed are:
- What is the “typical” Hadoop cluster and what should be installed on the different machine types?
- Why should you consider the typical workload patterns when making your hardware decisions?
- Are all microservers created equal for Hadoop deployments?
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