I have a TV and my monitor connected to my PC by a VGA switch box but what’s annoying is they aren’t the same resolution. This causes problems because I can’t see what I’m doing when I have switched to TV and usually have to leave the setting manager open so that when I [...]]]>

I have a TV and my monitor connected to my PC by a VGA switch box but what’s annoying is they aren’t the same resolution. This causes problems because I can’t see what I’m doing when I have switched to TV and usually have to leave the setting manager open so that when I change between them I just have to hit return and the resolution changes. That’s great and all but it’s far more effort than I want for something I do fairly often.

My plan was initially to create two xorg.conf files and switch between them using a script, I figured this would be the easiest way even though I haven’t messed around with xorg stuff for a few years ever since things just started working better in Linux. Turns out I couldn’t even find where they keep the xorg.conf file, it sure isn’t in /etc/X11 where it was the last time I looked..

On the search for this file though I came across another useful tool called xrandr, which essentially allows you to change the resolution from the command line.

Xrandr is used to set the size, orientation and/or reflection of the outputs for a
screen. It can also set the screen size.

If invoked without any option, it will dump the state of the outputs, showing the
existing modes for each of them, with a ‘+’ after the preferred mode and a ‘*’
after the current mode.

There are a few global options. Other options modify the last output that is spec‐
ified in earlier parameters in the command line. Multiple outputs may be modified
at the same time by passing multiple –output options followed immediately by
their corresponding modifying options.

For more information on xrandr check out the manual page (or type man xrandr in terminal).

It turns out it’s an extremely easy tool to use, with a command as simple as the following changing the resolution:

So the next thing I did was create the following script which allows the resolution to switch between 1440×900 and 1360×768 (my monitor and my TV native resolutions).

This script simply checks what the current resolution is being used and then toggles between the two set resolutions.

If you’re getting the following error while trying export a video under several different codecs in OpenShot including AVI, MOV and MPEG using (mpeg2, mpeg4 or h.264) chances are this might help you with that error.

The following formats/codecs are missing from your system:

libmp3lame

You will not be able to use the [...]]]>

If you’re getting the following error while trying export a video under several different codecs in OpenShot including AVI, MOV and MPEG using (mpeg2, mpeg4 or h.264) chances are this might help you with that error.

The following formats/codecs are missing from your system:

libmp3lame

You will not be able to use the selected export profile. You will need to install the missing formats/codecs or choose a different export profile.

This is a simple fix:

• Open up Synaptic Package Manager
• Search “libavformat”,
• If the current package installed is “libavformat52″ select “libavformat-extra-52″ (alternativly “libavformat-unstripped-52″ should also work).
• Else the package might be “libavformat53″ so simply change to “libavformat-extra-53″, basically it might end in different numbers, it should work the same.
• Hit Apply and approve the changes.

Errors:

$ dmesg usb rtl819xU:FirmwareDownload92S(): failed with TCR-Status: a rtl819xU:ERR!!! _rtl8192_up(): initialization is failed!

Solution 1:

To get this wifi dongle working I simply had to download the above firmware and place it in /lib/firmware/RTL8192SU/ and then reboot my computer. You should check that location [...]]]>

Errors:

Solution 1:

To get this wifi dongle working I simply had to download the above firmware and place it in /lib/firmware/RTL8192SU/ and then reboot my computer. You should check that location before hand and make a backup of anything inside of it if you’re not sure what you are doing. If it’s empty you can use the following commands to make the directory and then download the firmware directly.

Solution 2:

Alternatively download the source and build it:

Downloads:
Firmware: http://svn.debian.org/wsvn/kernel/dists/trunk/firmware-nonfree/realtek/RTL8192SU/rtl8192sfw.bin

Source: http://launchpadlibrarian.net/33927923/rtl8192se_linux_2.6.0010.1012.2009.tar.gz

For Christmas I got a Kindle 3 and it was instantly filled with Free eBooks (http://www.gutenberg.org/wiki/Main_Page) and research papers (PDFs). I found myself wanting to be able to automatically synchronize it with a folder on my desktop when it was plugged in and found no one else had posted online how to do [...]]]>

For Christmas I got a Kindle 3 and it was instantly filled with Free eBooks (http://www.gutenberg.org/wiki/Main_Page) and research papers (PDFs). I found myself wanting to be able to automatically synchronize it with a folder on my desktop when it was plugged in and found no one else had posted online how to do this, so I began researching into udev and rsync to get something working.

Setting up udev rules to run a script when the Kindle is plugged in.

Firstly, we need to find some parameters of the Kindle which are unique to it so that udev can identify that it is the Kindle being plugged in and not another USB mass storage device. We’ll need to find out where the device is mounted in /dev/ which can be a little tricky because this folder is pretty full.

An easier way to do this is to first, without the Kindle plugged in do the following command (list the directory and pipe the output to a file called dev1 in the home dir):

Now plug the Kindle in and redo the command, changing the destination output:

The difference between the two files will show what has changed in the /dev/ directory:

The output for mine (show in the image below) shows that 3 things changed when I plugged in the Kindle, sdb, sdb1 and sg2 directorys were added (shown by the > sign to the left). The folder I am looking for is the sdb1, this is where the mass storage device is found.

Write down where it’s found in /dev/ and then you can clean up those two files you previously made:

The next thing we want to do is use udevadm to collect some useful information about the device which we can do by the following command (I have chosen to pipe the output to a file called kindle in the home dir, because the output was pretty big. If you don’t want to remove the > ~/kindle from the end of the command):

WARNING: This can look pretty daunting but, (in the words of Douglas Adams) Don’t Panic.

While this many look daunting, what you want to do if find some attributes from the output which mean only your Kindle will be found when looking for them all, the problem I have found is that, with udev rules you cannot go too far down in the parent tree which stops me being able to use the Kindles serial to identify it. This could mean that my computer will sync any Kindle that’s plugged into it but I don’t have 2 to check. The following are the attributes I chose:

Now you’ll want to write the udev rule in /etc/udev/rules.d/

According to the readme the numbers represent the priority of the rule (higher overriding lower) followed by a descriptive name and it must end in .rules eg (xx-description.rules).

The following is the whole line I used for the udev rule, the only addition to the above is the RUN+=”/home/alex/.scripts/kindlesync.sh” which will run the script in that directory, this script contains the rsync command.

Save and close the file and then restart the udev service:

Writing a script to sync a folder on the Desktop with a folder on the Kindle using rsync:
Change the first directory from “/home/alex/ebooks/kindle_sync” to the directory on your computer where you want to keep the files that will be synced onto your Kindle and the second from “/media/Kindle/documents/sync/” to the location on your mounted Kindle where you want the files to be stored, save this file as kindlesync.sh. This is the script you call from the udev rules so for mine it’s saved as “/home/alex/.scripts/kindlesync.sh”.

Go to the location of the script and make it executable with the following command:

Now try plugging in your Kindle and make sure it syncs up!

Problems

In the udev rule, ACTION==”add” can be used to specify when the Kindle is first plugged in, however when trying to use this Ubuntu’s auto-mounting service mounts the drive after the script is ran so the sync becomes useless. Without this it runs the script 3 times, twice before it has mounted and then once it has mounted – this is currently the best I have found but it’s extremely messy.

Previously I was having problems with Ubuntu dropping wifi connections and failing to reconnect, to solve this I wrote a script which would kill the network-manager and then connect using iwconfig commands (here). While this works fine, it felt a little hacky, having to have a script running as sudo constantly in the background [...]]]>

Previously I was having problems with Ubuntu dropping wifi connections and failing to reconnect, to solve this I wrote a script which would kill the network-manager and then connect using iwconfig commands (here). While this works fine, it felt a little hacky, having to have a script running as sudo constantly in the background checking for a dropped connection. After a little searching I came across cron (the time based job scheduler ) and /etc/rc.local (a script which is run after all other initialization scripts have ran, allowing for scripts to be ran on startup) so from this I decided to split the old script up into connection and checking scripts which could be ran from init.d/local and cron, respectively.

Firstly my startup script in /etc/init.d/local which sets up and connects to the wireless network, open the file as sudo:

Paste in the following:

Next the script for checking the network is still connected, if not attempt to reconnect (named wirelesscheck.sh):

Make sure this script is executable (from the directory of the script):

Note: This is setup in the sudo crontab, only because this command needs root privileges – other commands could be added to a user crontab (by removing sudo from the following.)

Now, edit (-e) the crontab for sudo:

If crontab has not previously been used choose an editor (I used nano – 2) and append this line to the bottom of the file and change the frequency and directory of the script. The current settings will run it every 5 minutes (*/5) every hour, day, month and year and the file is located in “/path/to/script/wirelesscheck.sh”.

If you have any issues, leave a comment and I will help if I can.

If you’re getting this error but you’re still connected to the internet this page might help. This error is sometimes caused by repository’s which are down or broken.

From terminal run the following command:

If the output runs through a few [...]]]>

If you’re getting this error but you’re still connected to the internet this page might help. This error is sometimes caused by repository’s which are down or broken.

Failed to download repository information

Check your Internet connection.

From terminal run the following command:

If the output runs through a few repositorys but ends with something similar to the below (most probably with different repositorys failing) and ultimately stopping your updating process then there is a good chance you can fix it by just removing those failing sources from the software sources.

Err http://ppa.launchpad.net maverick/main Sources
404 Not Found
Err http://ppa.launchpad.net maverick/main amd64 Packages
404 Not Found
W: Failed to fetch http://ppa.launchpad.net/bugs-sehe/gparted/ubuntu/dists/maverick/main/source/Sources.gz 404 Not Found
W: Failed to fetch http://ppa.launchpad.net/bugs-sehe/gparted/ubuntu/dists/maverick/main/binary-amd64/Packages.gz 404 Not Found
E: Some index files failed to download, they have been ignored, or old ones used instead.

Software Sources can be found under either:

Applications > Ubuntu Software Centre > Edit > Software Sources..
OR
System > Administrator > Synaptic Package Manager > Settings > Repositorys

Click the Other Software tab.

Nnow find the repositories which caused the failure on the update and uncheck them and then close the Software Centre.

Re-run the update command and hopefully everything will work!

Check the example below where gparted was causing the error:

Having gone through several upgrades and countless repository’s added to the software sources, things can begin to get really messy really quickly and often begin to screw up when updating the system if you’re not careful. You may find yourself, like I have, wanting to restore your sources.list file back to its default in [...]]]>

Having gone through several upgrades and countless repository’s added to the software sources, things can begin to get really messy really quickly and often begin to screw up when updating the system if you’re not careful. You may find yourself, like I have, wanting to restore your sources.list file back to its default in order to get things working again.

In order to do this there is a pretty handy webapp available called the “Ubuntu Sources List Generator” - http://repogen.simplylinux.ch/

By moving through each section it enables you to select your country, release and then check each repository you want to add, not only does it support all the official ones for things like security and updates, it also allows for 3rd party repos such as Banshee, Chromium, Conky and VLC amongst a bunch others. Once you have what you want hit generate and it’ll create a nice, comment, new sources.list file ready for you to replace your old one with.

You may want to backup your old sources.list just in case with the following command:

Once you have that you can open the sources.list and simply paste the new one in from the repogen:

Paste, Save and Close the file and now you should paste the generated GPG keys, found just below the generated sources.list file, into your terminal.

Everything should be back to default and allow you to once again update everything.

A quick guide for getting pyrobot running in Ubuntu, I’ve managed to get it running on 32bit and 64bit Ubuntu (10.10) so follow the guide accordingly to whichever architecture you’re using (64bit is about half way down the post).

1. Download this file, or copy the below into a file and save it [...]]]>

A quick guide for getting pyrobot running in Ubuntu, I’ve managed to get it running on 32bit and 64bit Ubuntu (10.10) so follow the guide accordingly to whichever architecture you’re using (64bit is about half way down the post).

32-bit

1. Download this file, or copy the below into a file and save it as pyroinstall.sh to your home dir.

Note: The ‘ in the code highlighter I have above won’t work in terminal, there isn’t much I can do about it so you’ll have to re-write it. Also if you’re doing this manually change the “$currentdir” to “~” if you are doing it in your home directory.

2. Make sure this file is in your home directory (e.g /home/alex/pyroinstall.sh) and make it executable:

3. Run the usual way (as super user because it has to install stuff etc):

4. It’ll ask you some questions, below are the answers I used – you can use other configurations if you know what you need. I also put the full output in pastebin ’cause it was bunging up the guide - http://pastebin.com/Kc5jyhja

5. Once it’s done reboot or run:

6. Allow read/write/execute permissions for the pyrobot folder:

You should all be done, try typing the following to get it running!

64-bit

In order to get pyrobot running on 64bit, you basically need to add -fPIC to CFLAGS in all the relative Makefiles as explained in this mailing list post – http://www.mail-archive.com/pyro-users@pyrorobotics.org/msg00344.html - Lucky for you I’ve already gone through the effort of doing it and compressed it (download here you won’t need to if you are going to run the script though, it’ll do it for you..).

This script should download the file, configure and make and output the path to the .bashrc file for you (similar to the 32bit one does) so download this file, or copy and paste the script below into a file in your home directory:

2. Make sure this file is in your home directory (e.g /home/alex/pyroinstall64.sh) and make it executable:

3. Run the usual way (as super user because it has to install stuff etc):

Steps 4. 5. and 6. are the same as above..

Change Default Editor

If you want to change the default editor from emacs to anything else (this will change the default editor used in other terminal applications too..) use the following commands, just change gedit to whatever you’d like (vi, vim, kedit etc):

Any problems leave a comment and I’ll try and help as best as I can..

Attempting Boot From USB Device

SYSLINUX 3.63 Debian-2008-07-15 EBIOS Copyright (C) 1994-2008 H. Peter Anvin Unknown keyword in configuration file. boot: _

After creating a USB bootable version of Ubuntu from the Startup Disk Creator (or usb-creator-gtk) and attempting to boot, I was greeted by the error above. It might [...]]]>

Attempting Boot From USB Device

SYSLINUX 3.63 Debian-2008-07-15 EBIOS Copyright (C) 1994-2008 H. Peter Anvin
Unknown keyword in configuration file.
boot:
_

After creating a USB bootable version of Ubuntu from the Startup Disk Creator (or usb-creator-gtk) and attempting to boot, I was greeted by the error above. It might look a bit scary but it’s really easy to fix, just plug the USB flash drive into a computer (windows or linux, mac too probably but I haven’t tried that.)

Solution 1:

1. Open the the syslinux folder in the root of the flash drive.
2. Inside is a file called syslinux.cfg you’ll want to edit that.
3. Find the line “ui gfxboot bootlogo” and simply remove the “ui “.
4. Save and try booting again.

Below is how my syslinux.cfg file looks after editing:

Solution 2

Alternatively it looks as though there is another way of fixing this issue if there is no “ui” in the file, this is to do as followed (as pointed out in the comments below):

1. Type “help” and press enter
2. Hit Enter again

This should boot correctly and shouldn’t need to be done every time.

I have an updated fix for this issue using a startup script to connect and a time scheduled script for checking the connection, rather than having one constantly running in the background, avalible here – http://alexsleat.co.uk/2011/01/09/a-more-elegant-solution-to-ubuntu-wi-fi-reconnecting-issue/

I’ve been having some trouble with my wifi on Ubuntu recently but I think it’s because [...]]]>

I have an updated fix for this issue using a startup script to connect and a time scheduled script for checking the connection, rather than having one constantly running in the background, avalible here – http://alexsleat.co.uk/2011/01/09/a-more-elegant-solution-to-ubuntu-wi-fi-reconnecting-issue/

I’ve been having some trouble with my wifi on Ubuntu recently but I think it’s because I’m almost out of range of the access point. The problem is that once it disconnects it never seems to be able to reconnect unless wireless is disabled and re-enabled. No doubt there is another way of fixing this issue but it gives me a chance to write my first shell script.

In short the script disables network-manager (it was trying to do things auto which was screwing with things), sets up the connection and connects then checks for a string in the wireless card parameters which will only occur if it’s disconnected, if the string appears it’ll disable and re-enable the wireless device which seems to allow it to connect again. If it’s connected it’ll wait 3 minutes (180 seconds) before checking again where as if it does disconnect it’ll check again 30 seconds after it’s tired rebooting the device.

Here’s the script, be sure to try it if you’re having the same problem (you might need to change the wireless device ‘wlan1′ to yours) and comment if I’m doing something wrong or there’s another way around this, cheers.