Posts Tagged Linux
Sound not playing in AllStar Web Transceiver under Linux
Posted by MB in Uncategorized on November 13, 2015
A problem exists when trying to access AllStar’s Web Transceiver under Linux where no sound is played.
This is due to issues with Java under Linux.
A workaround is documented here.
Sound not working in Java apps in Ubuntu Linux
Posted by MB in Uncategorized on November 12, 2015
I tested Ubuntu 14.04 LTS in VMware. I started with a clean install. I made sure sound was working in the VM, then updated everything using this command:
sudo apt-get update && sudo apt-get upgrade
I then checked Software Updater and found a few more packages that didn’t get updated, and updated them.
I then made a backup of the VM to have a good baseline. I then installed OpenJDK 7 and the icedtea-7-plugin, using the following command:
sudo apt-get install openjdk-7-jre icedtea-7-plugin
I did not have openjdk-6, icedtea 6, or Oracle Java installed. If you do have any of those installed, try removing them to prevent any conflicts.
You can test your Java sound output any trying any Java applet that produces sound, such as this SoundApplet demo. If you don’t hear sound from it, you have an issue. If you have more than 1 sound device, check the other sound device for the sound output. In my case I only had 1 device (through virtualization), but it worked fine.
I also tried AllStar and was able to hear audio from the node announcements just fine, albeit with occasional crackle, perhaps due to the limited resources of the VM. I tried transmitting but did not get a reply from the few nodes I tried.
If you have something to add, please feel free to comment below.
Weather Underground forecast data in text display
Posted by MB in Uncategorized on November 11, 2015
One of the uses I found for my Raspberry Pi was using it to display weather data. I retrieved the weather data from Weather Underground using their API, parsed it, and displayed it on my RPi’s small LCD. This gave me an always-on view of the weather, which was nifty, and it was done all in bash scripting with a few external programs to parse the data.
This script is very customizable and extensible. You could use it to do any number of weather-related tasks.
I reduced the font size on the LCD to Terminus 6×12 using the following command:
sudo dpkg-reconfigure console-setup
This helped make room for all the forecast data on the tiny LCD. If you are running this on a PC, it’s not necessary.
For the smoothest updates, I have found it ideal to run the script under ‘watch’, as so:
watch ./weather.sh
I tired doing a ‘while true; do… clear… done’ loop, but the refresh rate was too low and the updates were not smooth.
Here is the script:
UPDATE : This has moved to github, here.
Last updated: 11-21-2015
Installing VMware Workstation serial on Workstation 9.0.2 in Linux
Posted by MB in Uncategorized on July 21, 2013
There appears to be a bug in the Linux version of VMware Workstation 9.0.2 in which it will not accept a serial number from the GUI. The solution is to open a terminal and install the serial manually.
Assuming your serial number is ABCDE-ABCDE-ABCDE (which it’s probably not, but you get the idea), do the following:
sudo /usr/lib/vmware/bin/vmware-vmx --new-sn ABCDE-ABCDE-ABCDE
Windows 8 error code 0x807800C5 during Windows 7 File Recovery backup
Posted by MB in Uncategorized on January 24, 2013
The following error appears if you try to include a system image in your backup using the Windows 7 File Recovery backup tool.
There was a failure in preparing the backup image of one of the volumes in the backup set.
Details: The mounted backup volume is inaccessible. Please retry the operation.
Error code: 0x807800C5
According to this forum…
For Win 8 only: The Win 7 back up program included with win 8 does not support backing up a image file to any kind of NAS device (UNIX, Linux) . Internally the program gives an error that the NAS device has an incompatible sector mapping type. You can backup to a hard drive that is attached to a different windows machine and then back up that file to your NAS. Convoluted, but it works.
So, backing up a system image to a Samba share is out of the question. To work around this, disable the creation of a system image in your backup.
I haven’t tried backing up to an NTFS-formatted iSCSI LUN, which might work. If anyone has tried that, I’d be interested to know the results.
Build and install Mozilla Spider Monkey (spidermonkey-bin) on Ubuntu Linux
Posted by MB in Uncategorized on January 4, 2013
Here’s how to quickly and easily build spidermonkey-bin from source on Ubuntu Linux.
sudo apt-get install mercurial autoconf2.13 hg clone http://hg.mozilla.org/mozilla-central spidermonkey cd spidermonkey/js/src autoconf2.13 ./configure make sudo make install
Enjoy!
Bash script to send contents of file containing URLs to Synology Download Station via API
Posted by MB in Uncategorized on January 1, 2013
This bash script will read a file containing a list of URLs line-by-line and send each of those URLs to a Synology DiskStation’s Download Manager via the published API.
Read the comments.
Note that, in user land, it might be easier to simply upload the text file to the Download Station. The below is useful if you want to programatically pass download tasks to Download Station, such as on the update of a web page, etc, etc.
UPDATE: This has been moved to github, here.
If you have any questions or comments on this script, please feel free to comment below. Thank you!
Simple Linux BASH script to locate and delete duplicate photos
Posted by MB in Uncategorized on September 15, 2012
This is a quick bash script I wrote to walk through directories and delete duplicate photos based on MD5.
It was written for a specific scenario and I highly advise against using it as-is. Instead, read through it and tweak it to your own situation. I would appreciate any feedback.
HF="$PWD/hashes.out"
echo HF=$HF
rm "$HF"
touch "$HF"
for x in `ls -bd *`; do
echo x=$x
cd $x
for y in *; do
m=`md5sum "$y" | awk -F '{print $1}'`
echo $y: $m
g=`grep $m "$HF"`
echo g=$g
if [[ "$g" != "" ]]; then
echo "MATCH!!";
echo rm "$y"
else
echo "no match"
echo $m >> "$HF"
fi
done
cd ..
done
How to retrieve EXIF data from the command line in Ubuntu Linux
Posted by MB in Uncategorized on December 17, 2011
If you want to make use of the EXIF data stored in a JPEG (.jpg or .jpeg) or TIFF (.tif or .tiff) file from the command line in Ubuntu Linux — or most other Linux variants — here’s how.
This was tested on Ubuntu 11.10 (Oneiric Ocelot).
First, you will need to have imagemagick installed to provide the identify command.
sudo apt-get install imagemagick
Next, you can retrieve the data on an image with the following example:
identify -verbose /usr/share/backgrounds/WildWheat_by_Brian_Burt.jpg
If you want just the EXIF data, you can use something like the following:
identify -verbose /usr/share/backgrounds/WildWheat_by_Brian_Burt.jpg | grep "exif:"
Set up an encrypted VPN using DD-WRT
Posted by MB in Uncategorized on December 13, 2011
DD-WRT is feature-rich alternative firmware for a large number of home router models. It adds a wonderful array of new features, VPN being one of them. This walkthrough will show you how to quickly and easily configure a PPTP VPN server on your DD-WRT-powered router, so you can connect to your home network from afar, create a secure tunnel so you can safely use a public Wifi point with your laptop, or secure your iOS or Android device.
Setting up the VPN Server
So here’s how to get started. First, you’ll need a build of DD-WRT supported by your router which includes the VPN software. If you’re doing this on an Internet connection which has an IP address that changes periodically (i.e. residential), you’ll likely want a Free DynDNS hostname to point to your IP address. You’ll also need a basic familiarity of networking.
For the remainder of this guide, I will assume your router’s internal (LAN) IP address is 192.168.1.1.
Start by going to http://192.168.1.1 and login to your router’s administration panel.
Go to Services > VPN and set PPTP Server to enable. After doing that, a few new options will appear. The only ones you need to set are Server IP, Client IP(s), and CHAP Secrets. Set them as follows:
Server IP: You can set this to your router’s LAN IP, i.e. 192.168.1.1
Client IPs: Set this to an IP range OUTSIDE your DHCP range (See Setup > Basic Setup to figure your DHCP range) A good example value would be 192.168.1.200-250 for clients to receive addresses within that range.
CHAP Secrets: This is the username/password combinations for your VPN clients. Format is:
username*password*
Example:
myname * mypassword *
Neither the username nor password can contain spaces, and must be all-lowercase.
You’re done with this page; Click Apply Settings.
Now go to Security > VPN Passthrough and make sure PPTP is set to Enabled. Click Apply Settings if you had to change the setting.
You should now be able to connect to your VPN using your Windows, Mac, or Linux computer by setting up a PPTP connection to your public (WAN) IP or hostname.
Troubleshooting
Can’t get connected? First, try setting up your connection to the router itself, using the LAN IP (192.168.1.1). If that works, then the VPN server is set up correctly; the problem is likely on the WAN side. Keep reading for suggestions. If you weren’t able to get connected, go back to the top and double-check your settings.
iOS-Specific changes
You may need to make the following settings adjustment if you are having trouble connecting specifically from your iOS device running iOS 4.3 or above. Go to Administration > Commands and paste the following in the box. Click Save Startup.
#!/bin/sh echo "nopcomp" >> /tmp/pptpd/options.pptpd echo "noaccomp" >> /tmp/pptpd/options.pptpd kill `ps | grep pptp | cut -d ' ' -f 1` pptpd -c /tmp/pptpd/pptpd.conf -o /tmp/pptpd/options.pptpd
(Source: DD-WRT Wiki)
If you can connect from the LAN side, but are still having trouble connecting from the WAN side, it’s likely your ISP or your gateway device (modem) is blocking the needed GRE protocol or the needed PPTP port or traffic. Contact your ISP for further assistance.
Do you have any experience or tips to share regarding VPN connections to a DD-WRT-powered router, or any suggestions in addition to the above? Please feel free to share them in the comments below. Thank you!
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