Tips ‘n Tricks :: Page 8

Archive for Tips ‘n Tricks – Page 8

Forcing a Device to Unmount in Ubuntu Linux

by Chris Jean

February 7th, 2009

I recently ran into an issue where a mounted SSHFS filesystem refused to unmount.

I tried to unmount it from inside Nautilus by right-clicking the mount and selecting Unmount, but this failed with an error message. The error told me that it couldn’t unmount the device and gave a reason of “mount disagrees with the fstab”.

I then edited the fstab (sudo vi /etc/fstab) and commented out the entry for the device. I tried to unmount in Nautilus again, but this time it told me that I couldn’t unmount the device because I wasn’t root and the device was not listed in fstab. I then uncommented the previously commented line and saved the file again.

Time to get dirty. I tried to manually run umount, but it failed:

[chris@home ~]$ sudo umount /mnt/share
umount: /mnt/share: device is busy.
        (In some cases useful info about processes that use
        the device is found by lsof(8) or fuser(1))
[chris@home ~]$

This was getting personal now as the previous messages said nothing about the device being in use. I closed out every application and tried again. Same error message.

I followed the instructions and ran man lsof followed by man fuser to find out more about those recommended commands. fuser was the winner.

fuser allows you to find out detailed information about processes that are using specific files or sockets. In addition to getting information, it allows you to kill processes accessing the file or socket. This was exactly what I was looking for.

After reading up on the fuser syntax, I ran the following:

[chris@home ~]$ sudo fuser -km /mnt/share
/mnt/share/: 9004c
[chris@home ~]$

This command basically translates into “find every process that is accessing the /mnt/share mount point and kill it”. Since I was unsure of the ownership of the processes that would be killed, I ran it with sudo to make sure that any processes could be killed.

The /mnt/share/: 9004c response means that a process with an ID of 9004 was terminated.

Again, I ran:

[chris@home ~]$ sudo umount /mnt/share
[chris@home ~]$

This command cheerily replied with nothing, which is a good sign as it means that the umount command succeeded.

Finally, the mount is unmounted. Now if only I could remember what I was trying to do when this problem happened…

Categories Linux, Tips 'n Tricks
Comments (15)

“cleaning soda off a motherboard”

by Chris Jean

February 5th, 2009

Every so often, I see some search result that led to my site that piques my interest. I think I’ll post about these when I see them and add them to my new category: Interesting Search. Every so often, I’ll select one of these search queries and try my best to provide the content that I believe that person was looking for.

To kick off Interesting Search, we have the search query “cleaning soda off a motherboard”. I have to say that I find this search both funny and very concerning at the same time. In all seriousness, having soda on your motherboard is a very bad situation. While I’ll focus on soda and motherboards, the information I provide here is valuable for anyone who has spilled any type of liquid or powdered chemical on an electronic device.

So what dangers does soda pose to electronics?

Categories Interesting Search, Tips 'n Tricks
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Dell Studio 17, Headphones, and Linux Mint

by Chris Jean

February 4th, 2009

A visitor to the site mentioned that he has the same laptop as I have yet is running Linux Mint rather than Ubuntu. He said that all the help that I was offering for getting Ubuntu to run well on the Studio 17 worked for him in Linux Mint except the headphone fix didn’t work. So, I dug in to see if I could find a solution.

I installed Linux Mint on my Dell Studio 1735 two nights ago and got the headphone jacks working successfully. Here’s step-by-step what I did:

Categories Linux, Tips 'n Tricks
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Partition Manager in Ubuntu Linux

by Chris Jean

February 3rd, 2009

Last night I needed to modify one of my partitions from inside Ubuntu Intrepid Ibex (8.10). I quickly realized that the familiar Partition Editor was nowhere to be found. I was quite stumped and looked through all the menus and didn’t find it. There is a simple reason for why I didn’t find it, it’s no longer installed by default on newer Ubuntu releases.

Fortunately, adding the Partition Editor, its true name is GParted, is extremely easy with package management.

Load Synaptic (System > Administration > Synaptic Package Manager)
Type gparted inside the Quick search box and click the Search button
Right-click the Package named “gparted” and select “Mark for Installation”
Click the Apply button toward the top of the window
Wait for the package to install

Now that GParted is installed, you can access it via System > Administration > Partition Editor.

Happy partitioning.

Categories Linux, Tips 'n Tricks
Comments (2)

Create ZIP Archives Quickly in Ubuntu Linux

by Chris Jean

February 2nd, 2009

Here’s a quick tip on storing a number of files into a single archive file quickly and easily in Ubuntu. The instructions will also work for those who use other distros as long as they are using Gnome and Nautilus.

Load up Nautilus (Places > Home Folder)
Copy all the files you want to store in the archive to a single location. For example, I’ll often copy all the files and folders that I want to add to my home folder first.
Highlight all the files to be included in the archive. You can select files and folders one at a time by holding down the Ctrl key while clicking on the desired file/folder.
Right-click one of the highlighted files and select “Create Archive…”
Name the archive and click “Create”.

Depending on the size of the files that you’ve selected, you’ll soon have a new zip file sitting in the folder where the source files are located.

Categories Linux, Tips 'n Tricks
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Unicode Support on CentOS 5.2 with PHP and PCRE

by Chris Jean

January 31st, 2009

Yesterday, I talked about how to get the most out of running regular expressions in PHP. The reason that I needed to dig in deep on regular expression syntax with PHP is because I needed to write some regular expressions that deal with Unicode characters.

After much reading, I believed that I knew everything that I needed. I started writing some regex strings and testing the code. Unfortunately, every time I ran a test with a string that contained Unicode characters, the match failed. When I removed the Unicode characters from the string and tested again, it would work. I was baffled.

Categories Linux, Tips 'n Tricks
Comments (69)

PHP Regular Expression Syntax References

by Chris Jean

January 30th, 2009

Since beginning work on my DNS Yogi site, I’ve had to do numerous regular expressions to matching all sorts of string bits. I quickly ran into problems when I realized that I need to add support for Unicode characters since certain TLD registrars support registrations with non-Latin characters.

The main issue is that there are multiple regular expression engines. PHP uses a flavor of the PCRE (Perl Compatible Regular Expression) engine. Each engine and varient of an engine has a slightly different way of handling regular expression syntax. I needed to find out exactly how the PHP regular expression engine worked, and finding that information was not easy.

Categories Development, Tips 'n Tricks, WordPress
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Headphones Jacks Now Fully Work on Dell Studio 17 Running Ubuntu

by Chris Jean

January 29th, 2009

A number of updates were installed on my machine yesterday. Ubuntu asked me to reboot, but I was busy, so I never ended up doing that yesterday. This morning, I booted my machine and was very surprised to find out that my headphone jacks no longer worked. Needless to say, I was upset.

As I discussed in a previous post, I’m running Ubuntu 8.10 (Intrepid Ibex) on a Dell Studio 17 laptop and getting the headphones to work required some workarounds. Basically, you had to set up the headphones to be line outs which caused one of the jacks to function but failed to mute the speakers when headphones were plugged in. This resulted in needing to manually mute and unmute the Front audio channel when you used or removed headphones. It’s because of this workaround that I thought the jack no longer worked.

Categories Linux, Tips 'n Tricks
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Using the Mic on a Dell Studio with Ubuntu

by Chris Jean

January 27th, 2009

I received a comment from John asking about using a mic with Ubuntu on a Dell Studio. I hadn’t tried to use my mic before, so I thought that it was time to try it out. After playing around a bit, I figured it out.

Categories Linux, Tips 'n Tricks
Comments (2)

Change Google favicon Back

by Chris Jean

January 23rd, 2009

Google’s original capital G favicon was around for, I don’t know, forever. Around June, they changed it to a lowercase g. I know that many people threw up their hands in disgust, but I actually liked it. It looked very clean and neat. However, they recently changed the favicon yet again.

Now Google’s favicon is this very colorful icon with green, blue, yellow, and red colors from their logo. I don’t necessarily dislike this new favicon, but I simply don’t and can’t associate it with Google. Google has always been represented by clean simplicity. They don’t need wizbang fancy images because they are simply good and don’t need to be fancy to attract people.

I think that’s why I liked the simple blue and white icon, even when they changed it. It was simple, to the point, laconic even; It was, in a word: Google.

Now when I have numerous Google tabs open, I look up at my tabs and just can’t help but think, “what is that site and why do I so many tabs of it?” I tried getting used to it, but I simply cannot. So, I decided that I would find a way to do something about it.

Categories Tips 'n Tricks
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