Archive for Ubuntu
I recently had a issue getting MySQL to read a specific database. Each time I tried to manually query a table in the database, I received the following error message:
ERROR 1018 (HY000): Can't read dir of './default/' (errno: 13)
I’ve seen this message before as it means that there is a permissions issue. I checked the ownerships and permissions, and everything seemed to be in order.
The only thing special about this database is that I have it symlinked to another partition. This has always worked in the past, so I was stumped.
The problem turned out to be that Ubuntu has AppArmor. This software sets up rules that prevent software from gaining access to different areas of the file system. In my case, AppArmor was preventing read and write access to the actual location of my database files.
The solution was quite easy: First, I added the path that I wanted MySQL to have access to in the AppArmor configuration file for MySQL. Second, I restarted the apparmor service. Here’s the technical details:
- On my system, the configuration file that controls MySQL permissions through AppArmor are located at /etc/apparmor.d/usr.sbin.mysqld. The following shows the contents of the file as it now exists:
# vim:syntax=apparmor # Last Modified: Tue Jun 19 17:37:30 2007 #include /usr/sbin/mysqld { #include #include #include #include #include capability dac_override, capability sys_resource, capability setgid, capability setuid, network tcp, /etc/hosts.allow r, /etc/hosts.deny r, /etc/mysql/*.pem r, /etc/mysql/conf.d/ r, /etc/mysql/conf.d/* r, /etc/mysql/my.cnf r, /usr/sbin/mysqld mr, /usr/share/mysql/** r, /var/log/mysql.log rw, /var/log/mysql.err rw, /var/lib/mysql/ r, /var/lib/mysql/** rwk, /var/log/mysql/ r, /var/log/mysql/* rw, /var/run/mysqld/mysqld.pid w, /var/run/mysqld/mysqld.sock w, /home/sites/default/mysql/ rw, /home/sites/default/mysql/* rw, /sys/devices/system/cpu/ r, }The two lines in bold show what I added to the configuation. The first line gives read and write access to the directory itself while the second gives read and write access to the files contained in the directory.
- After saving the configuration changes, I simply needed to restart the AppArmor daemon. I did this with the following command:
[chris@rommie ~]$ sudo service apparmor restart * Reloading AppArmor profiles Skipping profile in /etc/apparmor.d/disable: usr.bin.firefox
My dual monitor setup didn’t work properly in Ubuntu 9.04, Jaunty Jackalope. Fortunately, it does work properly in 9.10, Karmic Kaola. However, this newfound dual monitor setup has given me a new problem: how do I move my panels to the secondary monitor?
My office machine is a laptop. When I get in the office, I hook it up to a 24″ LCD. I’d like to use this external monitor as the primary, which means that I definitely want to have my panels display on it. However, as much as I tried to drag the panels around or play around with settings, there just didn’t seem to be a way to get them over there. However, I just figured it out.
By default, panels are set to expand. This means that the panels will span the entire width or height of the section of the window they occupy. If the expand option is disabled, they turn into self-sizing bar that can be dragged to different edges or centered.
Having the expand option disabled also allows you to grab and edge of the panel and drag it to another screen. Once on the screen you want it on, simply re-enable the expand option and you now have the panel on another screen.
Here’s a step-by-step way of moving a panel to another screen:
- Right-click the panel you wish to move and select “Properties”.
- Uncheck the “Expand” option under the “General” tab.
- Grab one of the edges of the panel by clicking on the left or right end (top or bottom end for vertical panels).
- Drag the bar to the desired screen and position.
- Check the “Expand” option in the “Panel Properties” window and click “Close”.
PEAR is PHP’s equivalent of Perl’s CPAN. It offers hundreds of ready-to-use code modules that can make projects go much more quickly than having to hand code everything. However, it never seems like PEAR is easy to get running.
Installing the Needed Software
In Ubuntu, installing the following packages will quickly get you started with PEAR: php5-cli, php5-dev, and php-pear.
Make sure that you read the next section about problems with using PEAR to install PEAR packages if you are running 9.10, Karmic Kaola.
Here’s an example of how to quickly install those packages from the terminal.
[chris@rommie ~]$ sudo apt-get install php5-cli php5-dev php-pear Reading package lists... Done Building dependency tree Reading state information... Done The following extra packages will be installed: autoconf autoconf2.13 automake automake1.4 autotools-dev libltdl-dev libssl-dev libtool m4 php5-common shtool zlib1g-dev Suggested packages: autobook autoconf-archive gnu-standards autoconf-doc gettext libtool-doc automaken gfortran fortran95-compiler gcj php5-suhosin The following NEW packages will be installed: autoconf autoconf2.13 automake automake1.4 autotools-dev libltdl-dev libssl-dev libtool m4 php-pear php5-cli php5-common php5-dev shtool zlib1g-dev 0 upgraded, 15 newly installed, 0 to remove and 5 not upgraded. Need to get 0B/8,690kB of archives. After this operation, 27.7MB of additional disk space will be used. Do you want to continue [Y/n]? y Selecting previously deselected package m4. (Reading database ... 127272 files and directories currently installed.) Unpacking m4 (from .../archives/m4_1.4.13-2_i386.deb) ... ...
With these packages, you are ready to roll with PHP and PEAR in Ubuntu.
Problem with Ubuntu 9.10 Karmic Kaola
A great thing about PEAR is that you can quickly install packages with a simple command. For example, “sudo pear install PHP_Parser-0.2.1″ will install the PHP_Parser package. However, this doesn’t work properly in Ubuntu 9.10, Karmic Kaola.
Output of the standard PEAR install command can be seen below:
[chris@rommie ~]$ sudo pear install PHP_Parser-0.2.1 downloading PHP_Parser-0.2.1.tgz ... Starting to download PHP_Parser-0.2.1.tgz (70,782 bytes) .................done: 70,782 bytes
While this doesn’t look wrong, it has actually failed. Rather than installing the package, it has simply downloaded the archive, encountered an unchecked error, and crashed. A successful installation has a message saying that the installation is successful.
This problem can be easily fixed by giving the install command the “-Z” option. For example:
[chris@rommie ~]$ sudo pear install -Z PHP_Parser-0.2.1 downloading PHP_Parser-0.2.1.tar ... Starting to download PHP_Parser-0.2.1.tar (Unknown size) .............................................................................done: 533,504 bytes install ok: channel://pear.php.net/PHP_Parser-0.2.1
Notice the “install ok: …” portion of the message. That’s what you should see at the end of a successful installation.
For more details on this bug, please check out Bug #451314 on the Ubuntu bug tracker.
I just encountered an odd issue with Ubuntu 9.10, Karmic Kaola. I had music playing in the background, I adjusted the volume, and I noticed that there wasn’t any change in the volume level. Even maxing out the volume and muting it had no effect.
After wondering if the problem was that I went insane, I looked in Sound Preferences (right-click the volume icon and select Sound Preferences) and found that “RV635 Audio device [Radeon HD 3600 Series] Digital Stereo (HDMI)” was selected under the device output. This means that Ubuntu was trying to send audio over my HDMI connection rather than through my headphone jacks.
This wasn’t a problem last night, so it might be due to the fact that my external monitor at the office runs over the HDMI connection, so it automatically switched to the HDMI audio output. In one way, this is nice, in another way, it will frustrate me to no end if it does this every time I’m at the office. If I’m right that it automatically switched upon detecting an active HDMI connection, then wouldn’t it be better to make it easier to provide a notification on where to switch the audio output rather than just switching it and causing confusion?
Switching the option to “Internal Audio Analog Stereo” instantly fixed the problem.
Oddly enough, when I manually selected the HDMI output again, it muted the analog output. So, it seems that it may not be a complete switchover or possibly just a bug. I’ll continue to see how the situation plays out and make a Ubuntu bug report if necessary.
Ubuntu 9.10, Karmic Kaola, launched earlier this week. One of the key new features in this release is Ubuntu One. Unfortunately, from what I’ve seen, this new feature/product launch has been anything but smooth.
Ubuntu One is one of the new ways that Canonical, the creators of Ubuntu, is trying to generate some revenue based on their distro. Ubuntu One is a hosted file storage solution that allows users to keep a folder and all of its content synced between multiple computers. All users get 2GB of storage for free with the option of increasing the store to 50GB for $10/month.
Since this new offering has many Ubuntu users very excited, I thought I’d give it a try as soon as I installed the new release. However, I was instantly met with a very big message telling me that something was wrong.
Continue reading “A Rough Launch for Ubuntu One on Ubuntu 9.10 – Karmic Kaola”
I recently tutored a friend in C coding. Since I hadn’t worked with C in at least 8 years, I really needed to have some references to rely on for syntax and other specifics. Fortunately, there are some easy man pages that can be installed in Ubuntu that offer helpful information that I was able to use to help refresh my memory.
These man pages are easily installed by installing the manpages-dev package. You can install this package via Synaptic or directly on the command line. I like the command line method personally, so I ran sudo apt-get install manpages-dev from the command line to quickly install the package.
After installing the package, I’m able to access man pages for functions such as printf, opendir, and putc. For each function, it shows the valid syntax as well as what library is required to make use of the function.
The information isn’t limited to functions as you can also access information on the libraries, such as stdio or string.
To access any of this information, simply run man [function or library name] such as man stdio.
This package isn’t limited to C functions/libraries. It is a general use Linux development suite of man pages. For a full list of what is installed, check out the file list.
In Linux, clicking the middle mouse button (or mouse wheel) pastes the most recently highlighted text from any application. This is useful; however, it has an extremely-annoying side-effect in Firefox. Whenever I middle-click outside of entry fields, I get an annoying pop-up that says: “The URL is not valid and cannot be loaded.” This frustrates me to no end. It usually happens when I accidentally nudge my mouse and miss middle-clicking a link in order to open it in a new tab.
So, why is it doing this? Turns out that, by default, Firefox for Linux allows you to use this middle-click to paste functionality to allow you to navigate to a highlighted URL simply by middle-clicking non-editable portions of the page. When an invalid URL is the result of the paste, the annoying popup appears.
Today, I found out how to get rid of this annoyance.
Open a new tab in Firefox and navigate to “about:config”. This will take you to an interface that allows you to tweak and configure very specific functionality of Firefox.
In the “Filter:” text box, enter “middlemouse.contentLoadURL”. This should present a single entry that lists the option as having a value of “true”. Simply double-click the listing to change the value to “false”. The effect is instantaneous.
Now when you middle-click outside of editable areas in Firefox, it will no longer try to navigate to a URL. This change only modifies the navigation to URL functionality; the middle-click to paste in editable areas still functions.
If you like the middle-click to scroll functionality found in other browsers/operating systems, then search for “general.autoScroll” and double-click the listing to change it to true. Now you can middle-click to initiate scrolling.
Firefox 3.5 was released yesterday. This is an exciting new release complete with features such as support for HTML 5, video and audio that works in the browser without the need for plugins, a much faster Javascript engine, a native JSON parser, private browsing mode, support for SVG transformations, and other great enhancements.
I’m sure that you’re just as excited to get started with Firefox 3.5 as I was yesterday when I heard the news. But wait! We’re on Ubuntu, we can’t just install whatever we want, we need to wait for a package. Right? Wrong.
Here’s a really quick way to get 3.5.5 running on your Ubuntu 9.04 system.
Continue reading “Upgrade to Firefox 3.5 on Ubuntu 9.04 – Jaunty Jackalope”
Now that I know how to do this, it seems so easy and straight-forward. To change the default application files of a specific type are opened with, do the following:
- Right-click a file that you wish to change the default application for and select Properties.
- Click the “Open With” tab.
- Select the desired application’s radio button.
- Additional applications can be added if the one you want is not listed. Use the Add button to find the desired application.
- You can also remove applications from the list by highlighting the application and clicking the Remove button.
- Adding applications to or removing applications from this list changes which applications are available in the “Open With” option when you right-click a file.
- Click the Close button.
Again, it seems so easy and straight-forward now. Go figure. 
It’s been a month since my last post. For all my regular readers, I’m very sorry for the absense.
There’s a lot of intersting stuff going on right now. Fortunately, with so much going on, I shouldn’t have a lack of topics to talk about.
To get the old post ball rolling again, how could I not start back up with Ubuntu 9.04?
Continue reading “Gaarai is Back and the Jackalope is Jaunty”