Debian: network not working after suspend

The problem:

When resuming from suspend, the network connection is lost. This happens whether using network-manager or /etc/network/interfaces. My network interface is Realtek r8169 (I found this with lsmod).

In /var/log/pm-suspend.log, I get the following message:

/etc/pm/config.d/unload_modules: SUSPEND_MODULES: not found

Solution:

1. Install packages acpitool and firmware-realtek.
2. Make sure the file /etc/pm/config.d/unload_module exists, and add this line:

SUSPEND_MODULES="r8169"

Eclipse - ActionBarSherlock

To get ActionBarSherlock examples working in eclipse:

• Download ActionBarSherlock (ABS) .zip or .tar file and unpack it somewhere.


• First import the library project with: File → New Project → Android → Android project from existing code. 
  Select the "library" subfolder of ABS as root.
  Tick "Copy projects into workspace" checkbox.
  


• Then import the samples project with the same steps above, using "samples/demos" subfolder as root.


• If you get "Call requires API level XX (current min is X)" errors:
  1. Go to Project Properties > Java Compiler. Use JDK 1.6. 
  2. Ensure you're compiling both the library and your app with Android 4.0+ 
  3. Ensure you're targetSdkVersion is 14 or higher.


• Then, if there are some errors remaining:
  1. Right click on project -> Android tools -> Clear Lint Markers.

Restart X (ctrl+alt+backspace)

The ctrl+alt+backspace key combination that used to do a hard restart of the X server has been disabled in many distros. This functionality can be achieved with the combination:

AltGr+Sysrq+k

Where Sysrq is the same Print screen or Prtsc key.

Also, the old ctrl+alt+backspace behaivor can be restored by following the instructions in https://wiki.archlinux.org/index.php/Xorg#Ctrl.2BAlt.2BBackspace_does_not_work.

Resize image to huge resolution with imagemagick

Recently I needed to print a 5-megapixel photo to roughly 1x2 meter size; the printing store wouldn't print it unless the resolution was at least 300 dpi, which, at that size, means a resolution of 500-megapixels!

Unfortunately, most image editing programs won't support so big files. One solution is to use ImageMagick from the command line. This should work in any platform supported by ImageMagick: Linux, Unix, MacOS and Windows.

First donwload and install ImageMagick from http://www.imagemagick.org.

From a terminal window, type the folowing command:

$ convert -monitor -limit memory 1GB -filter triangle input_file.jpg -resize 1000% output_file.jpg

The details of the different options can be found at http://www.imagemagick.org/script/convert.php, in short:

• convert is the ImageMagick tool that can (among many other things) resize images.
• -monitor is an option to display the progress of the operation. This is important to know what's happening, as the process may take several minutes.
• -limit memory 1GB. This limits the amount of memory used by ImageMagick Without this, the file failed to save!
• -filter triangle. This tells ImageMagick to use bilinear interpolation.
• 1000% was the resize factor I needed to produce the 300 dpi image at 1x2m, you can specify other percentage, different horizontal and vertical factors or a target width or heigth (or both) in pixels.

Apply cool effects to your webcam with http://www.monacam-app.com

Raspberry Pi: terminal "ls" colors for root in bash

To have the "ls" command output shown in colors for the root user, add the following line to the /root/.bashrc file.

alias ls='ls --color'

Note that, depending on the distribution you are using, this line (or something very similar) can already be present but commented out.

Apply cool effects to your webcam with http://www.monacam-app.com

Vibration units conversion

To convert sinusoidal vibration amplitude units, you can use the online calculator at:

www.cbmapps.com/appshelp/8

It handles displacement, velocity and acceleration; in mil, µm, ips (in/s), mm/s, ft/s², m/s², g; expressed in peak (pk), peak to peak (pk-pk) or rms amplitude values.

Apply cool effects to your webcam with http://www.monacam-app.com

Using webcalldirect in linux

To use the webcalldirect.com service in linux:

1. Install Ekiga if you don't have it. You can ignore the configuration assistant if you wish.
2. Set up a new SIP account (Edit -> Accounts -> Add a SIP account).
3. Use the following data, replace your own username and password:
   
   
   
   
4. You're done!

Know which version of Debian you are running

To know which version of Debian GNU/Linux you are running, execute this command:

$ cat /etc/debian_version

or (works for other distros, too):

$ cat /etc/issue