Archive for the ‘linux’ Category

Resuming SCP file transfers

Friday, December 12th, 2008

After a large file transfer using the UNIX command SCP failed at around 90% for the third time, I finally had the sense to google how to resume an SCP file transfer.

It turns out that you can’t. But you can tunnel RSYNC over SSH which works like a charm. This tip is posted in numerous places online, but my SSH setup at home is slightly different, so I have to modify the SSH option as follows:

rsync --human-readable --partial --progress --rsh="ssh -l username -p 2012"
domain.name:/path/to/file .

This just points out again how great a program SSH is. Its uses are truly multitudinous. It’s like the swiss army knife of UNIX commands.

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Upgrading to Debian Etch

Monday, April 9th, 2007

Today Debian released it’s first operating system upgrade in nearly two years, codenamed “Etch”. While Debian has received a lot of criticism recently over its long release cycle and internal politics, it remains a very stable, production-quality distribution that is simultaneously simple to maintain.

To upgrade my entire system I simply ran aptitude dist-upgrade and answered a few configuration prompts. Debian is by far the simplest to administrate of all the Linux and Unix systems I’ve maintained.

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Switching from Linux to Mac OS X

Sunday, July 16th, 2006

I recently moved from Ubuntu Linux on a Dell Inspiron to Mac OS X on a MacBook. Interestingly, the day before I made my purchase, Tim O’Reilly observed that a few long-time Mac-using programers had recently moved from Mac OS X to Ubuntu Linux. Because I was about to make the swich the other way, I posted the following reponse on O’Reilly’s blog:

Tim, I think your radar sense is on to something again. However, I’d like to offer myself as a counter example in that I am moving from Ubuntu to OS X this weekend when I purchase a MacBook.Ubuntu has impressed me as the most polished and feature-rich Linux distro I’ve used so far (among SUSE, Fedora, Debian, and Mandriva). I love that it improves on the robust Debian distro, offering fast development releases and an emphasis on usability. Ubuntu has improved a great deal in just its first two years of existence, and I fully expect alpha geeks and savvy tech users to adopt Ubuntu in favor of Mac OS X in the future. However, there are still several limitations to Ubuntu and Linux in general that are prompting me to move to OS X.

First, I find that Linux still requires a large degree of administration to work properly. I use several applications that require a kernel recompile every time a new version of the Linux kernel is released. Although I like the freedom of compiling my own kernel, the necessity of compiling the kernel in order to use the applications I need can be very frustrating.

Second, Linux lags behind Mac OS X and Windows in multimedia. Great strides have been made in recent years, but managing multimedia content is still difficult. Video editing and DVD authoring are especially salient sore points. Aside from the newly released Picasa for Linux, even managing photo albums is not as simple as it should be. Further, although Linux is so far DRM-free, this also means that Linux is shutout from online media content vendors such as iTunes and other music download services, and Warner Bros, Vongo, and others’ new movie download services.

Third, although software integration has improved, the large majority of software for Linux continues to feel disjointed and fragmentary when taken as a whole. Most applications don’t interoperate well with others. Simple things like dragging an image from a web page to an office document don’t work. As a result, the Linux desktop is a patchwork of powerful individual applications that never quite coordinate well enough to provide a satisfying user experience.

Fourth, neither Gnome nor KDE are as usable or as graphically appealing as Mac OS X or even Windows. I recognize that UI aesthetics and usability are not important for everyone, but I along with others note that the Linux UI is in many ways inferior to that of Windows XP, much less Vista or Mac OS X. Yes, XGL is becoming widely available, but XGL strikes me as a 3D-rendering novelty without good underlying usability justification.

I could list more complaints and others could doubtlessly add their own Linux quibbles as well. In sum, although I expect Ubuntu in time to become the power user’s distro of choice, Mac OS X still remains an unparalleled combination of UNIX and polished user experience.

Posted in apple, linux | 1 Comment »

VPN Client for Linux at GSU

Wednesday, May 17th, 2006

GSU requires a Cisco VPN client to access many of its network services. I use Linux on my laptop and unfortunately GSU does not offer support for a Linux client. However, after searching and trial and error I now have the Cisco VPN client working. I’m posting this for any interested GSU Linux users.

First, I looked into using VPNC, the open source Cisco-compatible VPN client because it doesn’t require the use of a new kernel module. However, VPNC requires the knowledge of a group password which GSU tech support declined to share with me (the official Cisco VPN client uses an obfuscated hash of the group password which VPNC doesn’t currently support).

I next turned to the Cisco VPN client for Linux. Below are the steps I took to get the Cisco client to work on my Ubuntu Dapper Drake version of Linux:

  1. Download the Linux kernel headers for your kernel version. Check your Kernel version using: uname -r
  2. Dowload the Cisco VPN Client version 4.8 for Linux. GSU doesn’t provide this, so try this Google search instead.
  3. Untar the archieve: tar -xzvf vpnclient-linux-4.8.00.0490-k9.tar.gz -C /usr/local
  4. Change directories to the new location: cd /usr/local/vpnclient
  5. Make sure the vpn_install script is executable (chmod +x ./vpn_install), then run: sudo ./vpn_install
  6. The installer will ask for the location of the kernel heard source. On my machine this is located at: /usr/src/linux-headers-2.6.15-22-686
  7. Choose “no” when asked if the Cisco file should start at boot time. After the vpn_install script ends, set the VPN_init file to start up automatically: update-rc.d /etc/init.d/vpnclient_init defaults
  8. From a Windows machine with the GSU VPN profiles installed (you can find the installer file which includes the profiles here), copy the PCF profile files to :/etc/opt/cisco-vpnclient/Profiles. Rename the PCF files so that the filenames do not include any spaces.
  9. After starting the vpn_init file (/etc/init.d/vpn_init start), start the VPN client by entering: vpnclient connect
    profile, where profile is the filename of one of the PCF files in /etc/opt/cisco-vpnclient/Profiles.

In all, this is a good example of why Linux isn’t quite ready for mainstream usage. However, Linux is a very powerful system that is becoming increasingly more user-friendly as a desktop system.

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Secure File Deletion

Friday, March 24th, 2006

I have a relatively new computer after my old Dell laptop failed while under warranty. Before returning my old laptop to Dell I decided to securely delete my hard drive to make my personal information unrecoverable.Secure file deletion is important because data can be recovered from even reformatted hard drives using tools like the Forensics Toolkit (FTK). However, most people don’t even bother reformatting their hard drive before donating their computer or throwing it away.

At any rate, I found a great secure deletion tool: Darik’s Boot and Nuke?or DBAN. DBAN is Linux boot disk that writes random zeros and ones over the entire hard disk according to secure deletion algorithms published by the US Department of Defense and Canada’s RCMP. DBAN also supports the Gutmann algorithm even though it is considered overkill by most experts.

If you want to securely delete a single file rather than an entire hard drive or partition, try GNU’s shred

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A Move to Ubuntu

Friday, December 9th, 2005

I switched to Ubuntu Linux a few months ago and I have been very impressed. Ubuntu is the fourth Linux distribution I’ve used in my three years as a full-time Linux user. Other distributions I’ve used (in chronological order) are Mandrake, Red Hat, and SUSE. Already Ubuntu is my favorite so far.

Aside from Ubuntu’s excellent hardware support, one of the main attractions of Ubuntu for me is its APT (advanced package tool) software package management system. Using APT, I can select from over 15,000 software programs to install, uninstall, or update at a click of the button. This makes software management very easy (which has not been Linux’s traditional strength). In Ubuntu, I was able to find APT packages for specialized security tools such as dSniff, Nikto, and TOR, all of which I had to compile from source on SUSE.

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