So I’m a pretty technical guy and sometimes I know what I want to do, but I have no idea how to do it with the latest version of whatever operating system I’m using. Typically these days thats usually a Linux flavor of some sort. I use it for my web-server, my file server and a few other things, but typically I set it up leave it and don’t touch it for a year or so. So instead of having to troll through man pages every time I want to do something, I started to keep a list of not-frequently used commands that I always seem to forget. So this is sort of an anti-FAQ for Linux. I mean if they were frequent, i wouldn’t forget!

Scan for viruses manually with clamscan – Most of this is excluding the test directories and system devices.

clamscan -ir –exclude=/sys/ –exclude=/usr/share/doc/clamav-0.95.1/test/ /

Firewall aka. IPTables
Block IP address – * for a range

iptables -I INPUT -s 192.168.0.* -j DROP

List IP’s instead of RDNS

iptables –list -n

Delete the 3rd rule

iptables -D INPUT 3

Remove file with crazy name – Ever mange to munge a filename so bad rm won’t remove it?

ls -il
find . -inum 124043383 -exec rm -i {} \;

Hard disk tweaking – not sure how much this helps but it helped me.

cd /sys/block/sda/queue/iosched/
echo 1000 > write_expire
echo 0 > slice_idle
hdparm -Tt /dev/sda

SMART Hard Disk Check- run smart report if you have a Highpoint controller that supports it. Remember to run a periodic short/long test. I’ve found the basic report is often inadequate.

smartctl -a -d hpt,1/1 /dev/sda

Yum locate dependency- some package failing because it needs some dependency? This was a real lifesaver.

yum whatprovides yourlibraryhere

Did something before but forgot? grep the .bash_history file, it seems to keep everything from the beginning of time.

iptraf traffic statistics- need to know traffic flow on your machine right now? Yeah you could do some sort of netstat command but I can never figure it out on the local platform (its “netstat -I en0 -w 1″ on OS X).
This app will give you all sorts of useful live statstics on your ethernet connections.

Next time – SELinux – all you need to know to setup your apache/php/centos webserver.

P.S. Any useful commands you use that you think might be helpful? Leave a comment :)

So I’ve been busy updating my programming skills by learning and creating an app for the iPhone. So I’ve not had a lot of time to actually post anything for awhile. But, I have started using del.icio.us as a way to post some interesting links that I don’t have the time to write about or post here…I was thinking of using the ‘press this’ thing here, but, that’s just going to create a bunch of posts and I’d prefer to keep some sort of quality standards.

So for fun random links I find interesting…

http://delicious.com/jriskin

I almost didn’t want to share this site with others because it’s so great! I’ve been using it since the early beta and it went public sometime earlier this year. Tineye is a ‘reverse’ image search. So you feed it an image and then it finds that image on other sites. But, its even better, it will still work if the image is cropped, sized etc… I’ll let them describe it…

TinEye is a reverse image search engine. You can submit an image to TinEye to find out where it came from, how it is being used, if modified versions of the image exist, or to find higher resolution versions. TinEye is the first image search engine on the web to use image identification technology rather than keywords, metadata or watermarks.

They have indexed over 1billion images and I’m sure that number is going to grow rapidly.

Example: Here is an image of britney and all the other possible sources.

Uses:

Identification: Can’t figure out who someone is? Often with a few links to other areas, their name will be mentioned, or in the file name, or in the other images.
Validation: Is someone seem too good to be true on that dating site? Suspec that myspace profile is fake?
Copyright: Is someone using your image?
Quality: Need a larger source image for your wallpaper, print project, or artwork? Maybe you just want to see a larger/cleaner image from some blog post that has been reblogged so many times all you can see is the thumbnail.

Go check it out, it’s one of my favorite new sites of 2009.

Over the years I’ve considered developing quite a few fun and interesting cell phone applications. Unfortunately, after developing some software to test and trying a dozen different cell phones some inherent physical limitations proved too large to overcome.

Most cell phones while having adequate resolution, are fixed focus lenses that can only focus about 2 feet away and farther. Much closer than that and the images become a fuzzy mess!

This totally destroys any hopes of some of the cool applications that can be made by barcode scanning products (e.g. price checks, order online) and scanning text (e.g business cards, subscription cards).

Imagine you walk in to a store in the mall and see something you like, but you’re not sure about the price. You scan it, and you phone opens google maps with all the nearby locations that have that product and the prices they charge. Things like this would be possible with the addition of a tiny bit of extra optical help…

Someday…

So full reinstall on the server, there were some broken things and wordpress got hacked (yet again) but I think we have it secure for the moment. Meanwhile I made some new business cards and wanted to share.

My friend Jonah had mentioned to me he used Gotprint.comto make some business cards and the quality was pretty decent. Having seen ‘digital’ printing in the past (I have a DTP background) I was a little skeptical, but realized it has been 6-7 years since I’ve tried anything and it has to be better right?

The answer is YES!

The Gotprint.com cards I had made for a paltry $20 are pretty decent! If I were to review them overall they would get the following grades:

A • Convenience
A • Price
A • Cardstock quality
B • Printing quality
B • Diecut quality
B • Speed (unless you pay extra)

Here are some samples from past cards I’ve made. Including some expensive high quality offset cards from around 2000, some medium quality offset (same year), an inkjet print from home and the Gotprint.com cards.

The high quality offset wins hands down, but they are expensive and take a lot more effort to find the right printer. The regular offset are still a hair better than the digital print in line quality but in absolute resolution the digitals are slightly better. So halftones will be smoother but the white lines are a little less solid. The inkjet has a great continuous tone look, but it sacrifices resolution as the same bleed that allows the smooth tones blurs out the sharp edges. I included it merely for comparison the paper quality can’t compare to real cards and cutting them also is an issue.

You might want to hold off on the unless you’re already experiencing problems like some new MBP users are. My latest not-so-scientific numbers show its a risky bet.

Check out my older post on the topic…

The graph is basically the number of positive to negative comments made on MacRumors.com.

The Volkswagen Key Disassembly continues to be one of the more trafficked pages on my site so I figured I would commit one more selfless act of community service and bring you the all-new Mazda Key Disassembly page. This particular key is from a 2006 MX-5 (aka. 3rd Gen. Miata, or Miata NC), bit will probably work just the same as many similar keys. I’m not even sure if what Mazda might charge for this, but I’m sure its more than the $1-2 cost to replace the battery and 5 minutes of your time. It could also be useful to replace the keychain link or clean the contacts.

Enjoy…

So I thought it might be a bright idea to illustrate what has to be one of the more over complicated HTPC (Home Theatre PC aka. PVR, Tivo thing, etc…) setups ever, mine… Ok, probably not, I’m sure plenty of people have crazier setups. But, it does surprise me how reliable it has been, even with so many computers involved. So how does it work? Magic! Ok, maybe not but something like this…

SageTV controls most of it. But, after trying numerous 1394 (a.k.a. FireWire) cards I never managed to get Windows XP, the Scientific-Atlanta SA-3250HD STB, and Charter Cable’s crappy signal to get along. Magically (Apple did create the standard for 1394) it just works without anything special on a Mac. So, FireWire is plugged in to the Mac, Sage TV controls it, all HD and digital channels go through the Mac and get recorded to the main media server/raid as raw MPEG-2 TS (transport streams). SD signals get recorded directly to the RAID through a Hauppauge PVR150 in the Windows box. All channels SD and HD are controlled through the 1394 (no infrared blaster silliness).

The great thing about this set is you get pure digital recording and playback all the way to the display. Digital cable -> Firewire digital files -> HDMI TV. The only other systems that work like this are DirectTV TiVo, some dedicated cable/sat. company PVR’s and Cable Card based systems. Unfortunately, after many years of unencrypted goodness, earlier this year Charter turned on 5C encryption on all HD pay channels. Note 5C is the digital encryption for the HDMI not the encryption that protects which channels you get which I believe is DigiCipher 2.

So what does the future hold? FIOS TV and the Hauppauge HD PVR Model 1212 likely. Unfortunately, this may mean losing pure digital recording/playback. But, I would regain recording of all HD channels.

The future is more likely the Internet and Bit Torrent. It’s really too bad for the studios that downloading bit torrent TV shows are often higher quality, more convenient and let you build collections as compared to the ‘legitimate’ offerings (Hulu, NBC online etc… and even recording SD/HD TV from cable/sat). But, this is a rant for another time…

Update: For completeness I added my parents Mac Mini to the full diagram (click the image), it runs Front Row Apple’s not so good PVR software, its slow over the Internet, but I believe that might be something about Samba. She can watch movies via the remote mount to my RAID and I put aliases in her Movies folder in her home directory.

Tag	Warning!
Connected	Disconnected

So have you ever purchased something or received a gift with security tag still attached? Quite annoying… well most of the tags were designed in the days where before rare earth neodymium magnets became so popular. They normally use powerful electro-magnets to disconnect these sorts of tags. Internally they are simply a spring loaded clamp that dis-engages with a strong magnetic force. If you don’t disconnect the clamp it will pull a metal pin that when pulled out breaks the two different glass die packs designed to stain whatever you disconnect.

So it took not 1, not 2, not 3, but 4 or more of these strong magnets before it came apart easily. Anyway, much easier and safer than trying to Dremel it apart and much more immediate gratification than having to wait for the store to open, driving back and having them remove it.

Oh and be good, this is not for you bad guys out there!

So if you ever wondered what happens if you screenshare in a loop, here is a nice fun picture =)