April 25, 2008

Ask Linux.com: Startup commands, cloning, and anti-virus software

Author: Linux.com Staff

In this week's peek inside the Linux.com discussion forums, we'll learn how to schedule commands to run every time at system start-up and what the Linux equivalents are for the disk cloning powers of Symantec Ghost. We'll also see a discussion about anti-virus software options for Linux, and whether or not they are worth the trouble to install. Plus, you'll get your chance to chime in with answers to tricky unsolved problems with virtual consoles and distributed filesystems.

Ghosts, Viruses, Pods, and more

User r2b2 posed the question about startup commands in the New to Linux forum, asking how to execute a command when the computer starts -- and, furthermore, what to do if the command in question requires sudo.

Readers asked r2b2 to elaborate, and it came out that the command that prompted the question was mounting a remote SMB (Windows) share. As user tophandcwby explained, that action is best handled by adding an entry to the /etc/fstab file, which allows you to specify both local and remote volumes to mount at startup.

But that was not the end: r2b2 still wanted to know how to configure general-purpose commands to run when the system starts. "When using debian and maybe ubuntu since it is derived from debian, to run a script at boot time, write the script and locate it at /etc/rc.local," tophandcwby replied. "During the boot up process the script in /etc/init.d/rc.local checks for /etc/rc.local and if it's executable, runs it. This script will be run with root privilege so sudo is not needed."

Two questions this week involved finding Linux-based replacements for important Windows utilities. User smhall05 wanted to find a replacement for Symantec's Ghost, a hard disk cloning utility known for its bit-perfect reliability. "I have used dd and dd_rhelp minimally in the past. Do these programs image the actual data only? If not, what programs can I use that are comparable?" User Penguin pointed out the differences between Ghost and dd's approach to data copying, and recommended looking at Partimage and G4L for a more Ghost-like solution. Khabi posted another possible alternative using the dump and restore programs, and gave a brief tutorial.

New Linux user (and new forum reader) zach asked if there were any anti-virus programs written for Linux in particular. Snowman responded with the three big contenders, the GPL-licensed Clam AV, and the proprietary F-Prot and AVG. Synthead took issue with the need, pointing out that the majority of computer virus target and exploit the Windows operating system. "At least for now, you have nothing to worry about. The only way an intruder can really get into your system is if they trick you to run code designed to harm your system," he concluded. "Another thing to keep in mind is that Linux is very different from many OSes. Many of the general guidelines taken to run other operating systems don't apply."

The need, or lack-of-need, for anti-virus protection on Linux is a hotly-debated topic, and one not likely to be settled soon. The same can be said about the merits of supporting proprietary technology like the iPod. User ler wrote in to ask for helping syncing his Linux machine with an iPod touch -- the newest model, and one different enough from its predecessors that it poses a unique challenge. Waxon pointed out an article that dealt with several iPod-supporting applications, but ler didn't find iPod touch support mentioned. User Synthead reassured ler that the touch was supported in the latest releases of gtkpod, and added some specifics to help get a working Firewire connection to the device.

Brains out, it's unanswered question time

If you don't have an iPod touch and you're not concerned about viruses, turn your attention to the forum readers that still have open questions. Efrain recently started using Compiz Fusion on a Gateway laptop, only to find that the mouse stops working after waking up from a suspend.

ImmerOhneGott has a virtual console (TTY) conundrum: although X sees the monitor correctly, the TTY does not, cutting of the bottom few lines of text, and thus making the shell impossible to use.

If troubleshooting isn't your thing, user Ratmonkey is in need of advice about working with the OpenAFS distributed filesystem. JimS is embarking on an unusual project -- building a headless Linux system to serve up Internet audio streams -- and he could use some success stories from others who have done similar work in the past.

Whether you have an answer for any of these posters or just an experience to share, click on the link to the thread and let readers know. Do you have a question of your own? Just visit the forums and ask away.


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