Sometimes, however, it is necessary to fool SSH into accepting an interactive password non-interactively. This is where sshpass comes in ....
With autossh, you can monitor your SSH connections and restart them if they stop sending traffic or SSH exits abnormally. This makes autossh perfect for keeping secure port forwarding available.
Which path should you follow? Should you take advantage of Ubuntu's package manager and use it to upgrade your system to the latest 8.04 Hardy Heron release, or should you download a CD or DVD ISO image and do a clean install? Common wisdom says that doing a clean install is the better, safer course of action. There may be a little extra work involved configuring everything once the latest and greatest is installed, but that's nothing compared to the pain of an update gone wrong, according to traditional thinking. But that cautious approach may no longer be necessary.
If you need to administer a remote server but don't feel like installing a complete, complex application like Webmin, try Web Console, a modern, over-the-Web, AJAX-based solution that's easy to configure and use.
Using toast takes the burden out of building, installing, and keeping track of software built from source. You can use toast to build and maintain software installed in your /home directory as a regular user, or to set up software for all users in /usr/local. toast can obtain packages over HTTP, HTTPS, FTP, and via SSH and CVS. It can handle most archive formats, as well as .rpm and .deb packages.
With tinc you can create a virtual private network (VPN) that lets you communicate between two machines over an insecure network such as the Internet with all of your traffic encrypted between the hosts on your virtual network.
Storage performance has failed to keep up with that of other major components of computer systems. Hard disks have gotten larger, but their speed has not kept pace with the relative speed improvements in RAM and CPU technology. The potential for your hard drive to be your system's performance bottleneck makes knowing how fast your disks and filesystems are and getting quantitative measurements on any improvements you can make to the disk subsystem important. One way to make disk access faster is to use more disks in combination, as in a RAID-5 configuration.
Got a question about Linux or free and open source software? You've come to the right place. In the left column of every page, directly below the Distributions link, you'll find a link labeled "Get Linux help" that will take you to the Linux.com discussion forums -- your best bet for getting Linux-related troubleshooting and advice, whether the issue involves hardware, software, or neither. Here are some examples of threads from recent days -- some with answers, and some still looking for solutions.
Developing a business model around free and open source software (FOSS) can be a delicate balancing game. Many companies in this space opt for models in which revenue comes from sources such as services, rather than the software itself. However, the recently announced LinMin is taking a different approach with a new appliance and imaging appliance: Although it runs and works on FOSS, LinMin's software is proprietary. The company's reasons for this practice raise several core issues about the relationship between FOSS and proprietary software on one hand and business priorities on the other.
Odds are, if you design Web sites with a database back end, you've worked with MySQL. You can manage this database from the command line, but it's not very user-friendly. Using the graphical tool phpMyAdmin helps, but not all Web hosting providers offer it or allow you to install it on the server. Fortunately, you can install it on your own box and manage several MySQL databases remotely at the same time, without having to install anything anywhere else.
Anyterm allows you to have secure terminal access to a server without needing any special software on a client machine beyond a Web browser. For example, with Anyterm you can open a terminal into your server from an Internet cafe. Because Anyterm uses a pseudo-terminal for communication with the shell, you can run most command-line tools from an Anyterm terminal running inside a Web browser.
In many organizations, copiers get little respect. Often relegated to a break room or storage closet, they are underutilized and underappreciated, and get no attention from the IT department. Yet, multifunction copiers can play a critical role in reducing operating costs and become a hub for document processing.
One of the main things that gets annoying with FUSE, or Filesystem in Userspace, is that it won't automatically mount a filesystem when you first attempt to access the filesystem. This means you must manually track mountpoints and specify what program to run in order to mount each FUSE filesystem. Placing the exact commands to mount each FUSE filesystem into shell scripts can make things a little easier, but with afuse, you can mount FUSE filesystems on demand without the need for any explicit mounting.
Session Initiation Protocol (SIP) is a popular open standard for implementing Voice over Internet Protocol (VoIP) telephone calls. Siproxd is a SIP proxy server that can help you with network connectivity issues for SIP clients behind firewalls.
The installation instructions in most free software reviews aren't enough. If you decide a package sucks, how do you get rid of it? If a package rocks, how do you upgrade it? GNU Stow, a package manager for packages you compile and install yourself, provides an easy answer to both questions.
One undeniable sign of progress among Linux distributions is the proliferation of easy-to-use, graphical package management applications. Tools like yum, Synaptic, and CNR are the rule these days rather than the exception. Mac OS X has free software fans, and a well-maintained collection of software at MacPorts, but for a long time those fans have been limited to the command line for finding, installing, and updating the offerings. Now a new utility called Porticus has arrived to present a slick GUI interface to the MacPorts collection, and it could make some converts.
The Linux kernel has merged three hypervisors into its mainline tree, starting with KVM in 2.6.20, and continuing with Xen and lguest in the 2.6.23 release of the kernel. Hypervisors let users run multiple operating systems on a host system. Lguest is the simplest of the three in terms of usability and implementation, which makes it a good candidate for helping you learn how virtualization works.
You're probably familiar with the live CD concept -- a fully functional operating system on a CD that can be run on any computer that boots from its optical drive, without affecting the one(s) already installed. In a similar vein, you can set up Linux to run from a USB hard drive drive on any computer that can boot from USB. The live system offers automatic detection and configuration of the display adapter and screen, storage devices, and other peripherals. A bootable USB drive can run a mainstream Linux distribution such as Debian GNU/Linux, and can be secured, personalised, upgraded, and otherwise modified to suit your needs.
With MySQLfs you can store a filesystem inside a MySQL relational database. MySQLfs breaks up the byte content of files that you store in its filesystem into tuples in the database, which allows you to store large files in the filesystem without requiring the database to support extremely large BLOB fields. With MySQLfs you can throw a filesystem into a MySQL database and take advantage of whatever database backup, clustering, and replication setup you have to protect your MySQLfs filesystem.
The /proc directory is a strange beast. It doesn't really exist, yet you can explore it. Its zero-length files are neither binary nor text, yet you can examine and display them. This special directory holds all the details about your Linux system, including its kernel, processes, and configuration parameters. By studying the /proc directory, you can learn how Linux commands work, and you can even do some administrative tasks.
The Simple Network Management Protocol (SNMP) is a useful tool for examining the state of devices on a network. The open source world offers a number of consoles designed to manage the information from these devices and produce reports. However, there are circumstances in which access to the devices at a more customizable level is more beneficial. Given that the programming involved is minimal, it is worth considering custom applications for SNMP reporting.