Linux

Our group is for the beginner, a regular user or an advanced user of Linux. Our topics are usually short and wide-ranging leaving lots of time for discussion and/or practice. We deal with installing and maintaining the Linux operating system along with its related software. Our topics also may be of interest to Apple or Windows computer users.

Contact: Dave Mawdsley. The Linux SIG meets on the 3rd Wednesday of the month at 7:30pm at the DACS Resource Center.

Yahoo! Group: linux_dacs

DACS Community Forum: http://forum.dacs.org/

News and Notes
Linux SIG Bits - May Report of the Meeting at the DACS Resource Center

Tonight's complicated meeting included a presentation "Vulnerability Scanning with 'lynis'", a demonstration running lynis, a second presentation "Introducing 'htop'", a study of the capabilities of the application "Mikogo" (http://www.mikogo.com/) along with the latency issues of simultaneous use of a USB video cam with Mikogo, and finally a short discussion about the possibilities of a DACS General Meeting presentation on converting a Windows XP computer to a Linux distribution such as Ubuntu.

"Vulnerability Scanning with 'lynis'" (Is my computer configured properly?)
First this evening was my LibreOffice Impress slide show used to describe the Linux utility "lynis".  Lynis scans a computer or server for an extensive list of mistakes in settings that could result in security breaches in the system.  (Using ClamAV, an anti-virus tool, or rootkithunter, a root kit scanning tool is not enough.)  Lynis gives an extensive report card listing "Warnings" that should be attended to right away, and "Suggestions" that might point to other issues of lesser importance.  What's nice about the utility is that the results are put into log files that can be examined repeatedly after lynis has completed its run.  (This presentation can be downloaded from http://madmod.com/lynis.odp and run if you're using LibreOffice or OpenOffice.  [odp: open document presentation])

Lynis was then run on my laptop and it flagged a few warnings about vulnerabilities that I would have to fix.  I chose to fix an issue about secure shell (SSH) that concerned allowing root access.  The fix involved an SSH configuration change from "AllowRootAccess yes" to "AllowRootAccess no" followed by a restart of the Linux SSH utility.  If later I were to run lynis again, the root access issue would be graded "OK" with the remaining warnings still shown.

"Introducing 'htop'" (What resources are running on my computer and how is the computer coping?)
Next, Jim Ritterbusch presented "Introducing 'htop'".  Htop is another Linux utility that is a gem of a replacement for the standard 'top' utility.  'Top' allows the user to see the running applications, processes, memory usage, disk usage, priorities, uptime, etc. for the purpose of either killing an application hogging resources or to see the general performance of a system running numerous services and applications.  (Windows users are probably familiar with the "three finger salute" of Ctrl+Alt+Delete which brings up a "Windows Task Manager".)  While 'top' gets the job done and is widely used, it's nowhere near as flexible as the utility 'htop'.  'top' can be be started with various options controlling the display, but it lacks the ability to look at trees and the performance of the separate processor cores of the computer.  'top' allows for keyboard control, but 'htop' allows for mouse control as well.  'htop' allows for display changes and other options from a list at the bottom of the display.

From the point of view of server administration, 'htop' is thus preferred over 'top' as a way to manage resources of a server.  In particular, close study of those processes connected with, say, a webserver or database server sharing the same physical computer, could be made easier, e.g. looking for memory or CPU choke points, or unnecessary services.

Using Mikogo (a remote video sharing tool)
Bruce Preston attended our meeting remotely by use of the application Mikogo on his Windows laptop and my Ubuntu laptop.  Mikogo, which works on Windows, Apple and Linux platforms, allows the session leader's computer screen to be copied to the remote user's computer screen.  My computer was connected to the presentation projector, so that the presentation could be seen by everyone attending our SIG.  Simultaneous use of Skype allows for audio participation as well.  With Mikogo and the audio of Skype, remote attendees can fully enjoy the SIG meeting but without seeing the participants.  Mikogo, while free for simple use, has a paid version with extra features.

Additionally, we tried to use a USB video cam with the Linux utility "Cheese Webcam Booth" on my computer to allow for Bruce to see our meeting room and other attendees as well, but we discovered that latency issues made for unacceptably long delays, with page imaging caused by network slowness and other things slowing up the two computers.  Perhaps an improved method of using the USB video cam can be found for future meetings.

DACS General Meeting Topic Discussion
Last this evening, Bruce brought up the possibility of a DACS General Meeting topic on the repurposing of old non-working Windows XP computers to free Linux distributions such as Ubuntu, Fedora or Linux Mint.  Since the distribution install process takes quite a while and it usually needs to get updates from the Internet, it was thought that a PowerPoint-like slide show with perhaps a video of a previous distribution install might be useful and interesting.  Also considered was the acceptability of using 6+ year-old hard disk drives of the Windows XP machine for the new Linux distribution, thus attempting to extend a worn drive's useful life still more years.  As an alternative, I recommended replacing the old hard disk drive with a new one before attempting a distribution installation on an old computer.

Next Linux SIG Meeting
The June 19th meeting topics will include:  "Infrared Communication with the Arduino Uno" and continued discussion about using the Raspberry Pi to run weather station components.

If these items connect with your interests, join us at our next meeting in the DACS Resource Center of Ives Manor.  Bring your laptop, Arduino or Raspberry Pi and show us a thing or two.  Our meetings are for the beginner, intermediate or advanced user, so topics vary considerably depending upon the needs of the attendees.