Ryan Rampersad » Linux

★ After Oneiric Ocelot – Ubuntu 12.04

Ryan — Sun, 17 Jul 2011 17:17:16 +0000

My dad and I were trying to figure out what would come after Oneiric Ocelot or Ubuntu 11.10. Well, you can read some of the suggestions for the 12.04 name.

Some of my favorites are:

Perpetual Phoenix
Philosophical Pegasus
Pragmatic Penguin

★ restart: Rejected send message – Ubuntu Lucid

Ryan — Tue, 28 Jun 2011 17:46:37 +0000

I installed a little ftp-server on my ubuntu dev-server. After configuring some ports and other users, I needed to restart the service. Since most daemons run as services now, anything /etc/init.d/name restart is now just service name restart. But of course, nothing is that easy.

ryan@ryan-desktop:~$ service vsftpd restart

I ran this to restart the service for the ftp daemon but I was rejected.

restart: Rejected send message, 1 matched rules; type=”method_call”, sender=”:1.120″ (uid=1000 pid=26611 comm=”restart) interface=”com.ubuntu.Upstart0_6.Job” member=”Restart” error name=”(unset)” requested_reply=0 destination=”com.ubuntu.Upstart” (uid=0 pid=1 comm=”/sbin/init”))

Isn’t that a fantastic message? Well, the solution dawned on me quickly. I needed root permissions. So a quick sudo !! fixed the problem now, or just running sudo service vsftpd restart.

Happy ftp-ing.

★ IP address from hostname – Ubuntu Lucid

Ryan — Wed, 22 Jun 2011 19:10:19 +0000

If you have an IP address but you don’t have a hostname to go along with it, you can easily get it via Ubuntu’s host command.

For instance, I have an IP, 97.115.69.11, and I needed the hostname. To get it, I simply ran host 97.115.69.11.

ryan@ryan-desktop:~$ host 97.115.69.11
11.69.115.97.in-addr.arpa domain name pointer 97-115-69-11.mpls.qwest.net.

Happy IP-grabbing.

★ Do Nothing on Lid Close – Ubuntu

Ryan — Tue, 17 May 2011 18:45:55 +0000

I took my parents old 32-inch flat screen TV into the basement and hooked it up to an old laptop I had just sitting around. With Ubuntu on it, I wanted to keep it shut and tucked out of the way, and just remote in whenever I wanted to do something with it. Great idea, right?

For some reason, Ubuntu’s 10.04 Gnome does not have a do nothing action for when the lid closes on the laptop. You have blank screen, which is normally fine but it cuts VGA/HDMI output. There are suspend and hibernate which would be rather useless in this situation too.

Well, as with many things you are not supposed to do as a regular user, you can in fact get around the lack of this option. While not exposed via any public control panel, the Configuration Editor has the setting.

Open the terminal and run sudo gconf-editor. Once the window opens up, you’ll see a bunch of closed trees. Navigate through the trees: apps > gnome-power-manager > buttons. Once there, you’ll see the settings and their descriptions for the setting values.

The description for lid_ac, that is, when the lid closes while plugged in is:

The action to take when the laptop lid is closed and the laptop is on AC power. Possible values are “suspend”, “hibernate”, “blank” and “nothing”.

It strikes me that gnome should know enough to put the nothing choice in there. Finally, change the lid_ac setting to nothing, the word nothing, not blank, and then close the editor. Restarting Ubuntu will put the new setting into effect.

That should do it!

★ Install the Latest Google Chrome on Ubuntu

Ryan — Sat, 05 Mar 2011 22:53:14 +0000

If Firefox is too slow for you now, Google Chrome might be worth it. I’ve used the Ubuntu Software Center since I started using Ubuntu last year to grab Chrome from the official open source channels, but lately it’s been outdated because Google releases Chrome at the speed of light.

Since the USC is slow to update you’ll end having to wait a much longer time to get updates. To fix this, skip the USC altogether and go straight to the source – Google. The Google Chrome website automatically detects the OS you are using so you have to do this on Ubuntu directly. Once there, do not click Download Google Chrome! Instead, look below it for Try the latest BETA version or
Get Google Chrome beta or developer releases which will ensure you always have a cutting edge more than up to date version of Chrome.

On the next page, you’ll see the Early Access Release Channels header. Scroll way down to Subscribing to a channel and then to Linux. Look for Beta Channel. You’ll need to pick either an x32 or an x64 version to download. Once you click the link, it’ll bring you to the beta release page and show you the Google Chrome terms of service. Accept and the download should start.

You’re downloading a .deb file so it is basically an installer. If it doesn’t open automatically upon finishing, just go to your downloads folder and click on it a few times. Once the installer is open, click Install Package and then enter your password if prompted.

Once it’s installed, you should take a look in the Applications menu: Applications > Internet > Google Chrome. You’ll see the new Google Chrome browser right there.
Another thing I’d like to point out is the difference between the icons. Looking at the icons – the bland blue washed icon is the open source Chromium while the colorful icon is the true Google Chrome.

Now you can use Google Chrome and it’ll be always mostly updated!

Finally, I was looking for a reliable way to transfer or import the Chromium profile into the newer Chrome. However, on Linux, it doesn’t appear to be very straight forward so I’ll leave that for another day.

Enjoy Google Chrome on Linux!

★ SSH: Remote Host Identification Has Changed

Ryan — Thu, 25 Nov 2010 00:17:56 +0000

I recently reinstalled a Ubuntu machine on my network. I often log in to that server machine via SSH on my laptop. I received a scary message when trying to do so.

ryan@ryan-laptop:~$ ssh ryan@192.168.2.67
@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that the RSA host key has just been changed.
The fingerprint for the RSA key sent by the remote host is
8e:69:91:6b:d5:8e:ac:ef:2e:2f:69:8e:97:4a:c4:28.
Please contact your system administrator.
Add correct host key in /home/ryan/.ssh/known_hosts to get rid of this message.
Offending key in /home/ryan/.ssh/known_hosts:1
RSA host key for 192.168.2.67 has changed and you have requested strict checking.
Host key verification failed.

This took me by surprise. My network is secure as far as I know, and the only difference now is the that I reinstalled my server with a fresh copy of Ubuntu 10.04. When SSH is installed I guess it makes a new RSA key and it’s not based on hardware or anything silly. That makes sense, I guess.

Fixing the error at least on the laptop was effortless. First, I opened the terminal. Then, I ran cd /home/ryan/.ssh/ and then opened the file via vim known_hosts. And I saw a mess of characters appear on my screen. The error message said I could update key 1 but it looked like there already multiple key 1s.

My solution was to simply delete the known_hosts file with rm known_hosts and remake it with touch known_hosts. That was easy enough. Then, I tried to run my ssh command again, ssh ryan@192.168.2.67. It prompted me that this computer has not been accessed before and it isn’t an already trusted key. That’s great, because I did trust it and I accepted it. That means deleting the old file and remaking it worked. Excellent.

ssh happy@sshing-computer.

I knew the cause of this error pretty fast because I reinstalled my server. However, getting this error while out at a Starbucks would have tipped me off that something more sinister was going on. Keep in mind that with this error, it can mean the finger print is different or that someone is in fact spoofing the remote’s host name or IP address.

★ Change default git editor on Ubuntu

Ryan — Thu, 18 Nov 2010 20:25:25 +0000

On my new Ubuntu laptop, I installed git one day and was making a commit not long after. I was surprised with an editor that I never use: nano. I wanted VIM.

First, make sure you have the text editor you want is installed. In my case, I wanted VIM, so I ran: sudo apt-get install vim. It turns out that ubuntu doesn’t come with VIM installed by default. So it installed without any trouble.

I was reading this Stack Overflow thread about doing setting the core.editor property, but it didn’t work. It turns out that the simple command, git config core.editor "vim" doesn’t set the property for all git repositories, just the local folder. If you try to do it in a non-repo folder, it’ll scream at you:

error: could not lock config file .git/config: No such file or directory

The solution is of course to add a global option. Run the same command but with global enabled, and it’ll set all repos to use the same text editor: git config --global core.editor "vim". Note the two dashes, that’s very important.

That’s all there is to changing the default editor for git in Ubuntu.

★ Directory Size with Linux Terminal

Ryan — Wed, 27 Oct 2010 22:19:18 +0000

I needed to find out the size of a directory while connected to my Ubuntu server. When I used the properties menu in Windows explorer however, that data was not populated so I needed an alternative – the terminal. It turns out that using the terminal to find the directory size is incredibly easy.

The basic syntax for finding the directory size in Linux is goes like this: du [options] /path/to/directory. Running the command without any options will show you the size of each sub-directory and as well as the total as the last line in the output. But there are a bunch of helpful option configurations. You can always see du --help if you want more.

du -h – formats sizes according to kilo, mega, and gigabytes.
du -hc – produces a line with the word total at the end
du -hcs – skips displaying size for sub-directories.

That’s all there is to finding the size of a directory in Linux.

★ Remove Ubuntu Boot Loader

Ryan — Thu, 07 Oct 2010 20:20:33 +0000

I tried to install Ubuntu 10.04 on my HP dv6-2150us laptop but I was greeted with no wireless networking so I promptly erased the Ubuntu partition. After restarting, I got an error from grub stating that was no operating system. I knew I had to restore the Windows Boot Loader.

I thought the Windows 7 automatic repair system would kick in eventually, but it didn’t. Moving along, fixing the problem is incredibly easy. You’re going to need a Windows 7 installation disk. I had a Windows 7 Home Primium disk lying around, so I used that. I don’t know if a recovery disc you made will actually work, but you can try it.

Put your Windows 7 disk (W7D) in the optical drive and start up the computer. Then, boot from CD. Since I was using an HP laptop, I needed to hit escape and then hit F9 to boot from disc. You’re computer may be different. Once you boot into the disc, it’ll ask you to pick a language and keyboard setup. Just pick whatever you like and hit next. Now, you’ll see a huge Install Now button. Don’t click it. Look below it for Repair.

Once that comes up, you’ll see a few options but look for open command line. You’ll be entering a frightening command line. Once the command line opens up, enter Bootrec.exe /FixMbr. If the command works, it will say it was successful. That should be it, close the command line window and hit the restart button.

Good luck!

★ Cleanup an Eclipse Workspace Directory

Ryan — Thu, 09 Sep 2010 05:18:12 +0000

After an incredibly short summer, I needed to clean up my flash drives. I ran Eclipse on a workspace stored on one. All my source code for every project was stored neatly and distinctly in their own project folders. Of course Eclipse stores all sorts of meta data and even the compiled classes in those project directories too. Since I wanted to donate my code base to my old teacher, I needed to clean it up.

I tried to use the Windows Command Prompt, but I totally failed. So I quickly whisked my files over to a temporary directory on my Linux server. Once there, I could leverage the awesome power of the terminal.

There are four major things to remove in the Eclipse workspace directories: /bin, /.settings, .classpath and .project. So we know what to target. I used the follow four commands (but surely could be merged into a single line by an expert!):

rm -rf */.settings rm -rf */bin rm -rf */.classpath rm -rf */.project

I should note that before running those commands, I copied the original directory to make a backup. Please, make a backup! because you don’t get to recover from the Terminal’s rm command.

When you inspect your workspace directories, you should notice those four things gone. It’s really that easy!

Happy eclipsing.