Technology Insights

Ubuntu Equivalent Of yum whatprovides On CentOS

In the past I used CentOS Linux the open source RedHat Enterprise Linux clone but these days I find myself using Ubuntu Linux more and more often because so many more packages that clients want installed are more up to date. One command I used to use on CentOS all the time was the yum whatprovides command which would allow me to search for specific applications, scripts, libraries, etc. to figure out what packages I needed to install. The command that is similar on Ubuntu is apt-file which does not come installed by default. Below I show the output of an example yum whatprovides command on CentOS Linux followed by what needs to be done to use apt-file on Ubuntu Linux.

Technology Errors

Error Failed Dependencies: is needed by nxclient-3.4.0-7.i386 Installing NX Client

While looking for a light weight way to run XChat all the time without having to disconnect every time I shutdown my laptop I discovered NoMachine NX which is easy to install, configure, and use. It provides remote X sessions and is fairly reasonable in terms of bandwidth. When installing the NX Client on one of the CentOS servers I was installing this on I ran into an error complaining about libaudiofile. Below I describe the error in more detail, how I located the package to install, and show the package being installed.

Technology Insights

How To Unjailbreak GreenPoison, Remove GreenPois0n From Your iPhone

I had been wanting to jailbreak my iPhone 4 for quite awhile but since I had upgraded to Apple iOS release 4.2.1 there was not an untethered jailbreak available at the time and since I typically turn my iPhone completely off I didn’t want to deal with the untethered jailbreak. So needless to say when GreenPois0n rc5 was released I was pretty excited. GreenPois0n rc5 made it extremely easy to jailbreak iPhone’s running iOS 4.2.1. After running it for around a month now though I noticed that I really don’t install enough applications outside of what is available via the iTunes App Store to warrant the jailbreak and especially because I have personally noticed that with my iPhone jailbroken it had slowed down a bit. Not only had it slowed down but my battery appeared to be draining much quicker which I assume was from more processes running. I made the decision a couple days ago to roll back to the stock iPhone 4.2.1 firmware to see if my phone started running more efficiently. Below are instructions for rolling back the GreenPois0n firmware on an iPhone 4 to the Apple iOS 4.2.1 firmware release.

Technology Insights

iPhone Custom Ringtone Not Showing Up, iPhone 4 Ringtone Not Working

I finally got an iPhone 4 and decided to create some custom ringtones to try out on it. The first one that I created, using the method we documented in this previous article, is the sound of a dial-up modem connection. After creating the ringtone by converting an MP3 file to an m4a and then renaming then m4a to m4r I attempted to sync the iPhone to iTunes to copy over the new custom ringtone however it was not available in the Ringtone Sounds configuration section on the iPhone 4. After troubleshooting I finally figured out a solution which is documented below.

Technology Insights

Clean Macintosh iTunes Library By Batch Removing Dead Tracks

A friend asked me to help him clean up his iTunes library on his iMac the other night so I asked him to bring it by. When he did I realized what had happened which is he had moved the location of his iTunes folder from his computer to an external drive. After moving the folder he imported all of his music again which caused iTunes to think his 8,000 MP3’s had become 16,000 MP3’s. Half of the tracks had red exclamation points by them because iTunes had information about them but could no longer locate the file since he had moved all of the music to a new folder in a different location. I found an easy solution to resolve this problem on a Mac which I describe in detail below.