Category Archives: Linux

Using Image Magick to shrink your JPGs

Here is a small script to use Image Magick tools on the JPEG files from your camera, and create “smaller” versions in a new sub-folder called “smaller”.

It must be changed to match the JPG files produced by your camera. It looks for JPEG files with specific dimensions.

And of course this version only works on Unix-like systems that have the “bash” shell available.

rm -f list.txt
mkdir smaller

echo List of JPG files
for a in P*.JPG; do (identify $a >>list.txt); done

echo convert 4032x2272 images
for a in $(grep -e "2272" list.txt | sed -re "s/^([^ ]+).*/\1/"); do (convert $a -comment "Copyright Robert Echlin. Larger version available." -resize 1920x1080 smaller/$a ); done

echo convert 4032x3024 images
for a in $(grep -e "3024" list.txt | sed -re "s/^([^ ]+).*/\1/"); do (convert $a -comment "Copyright Robert Echlin. Larger version available." -resize 1600x1200 smaller/$a ); done

echo checking ...
echo Local files
ls *JPG | wc -l

echo smaller files
ls smaller | wc -l

I installed Ubuntu 12.04 on a machine at work, using the WUBI installer. When I did an update, it complained like this:

W: A error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: precise-security Release: The following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key <>

It turns out that i was not authorized on the WIFI when I tried to do the update, so of course it failed. The real issue is that it managed to mess up the APT cache, so it kept on failing, even after I had the WIFI running.

The fix, from Ubuntu Forums, was to clear that cache.

cd /var/lib/apt
sudo mv lists lists.old
sudo mkdir -p lists/partial
sudo apt-get update

Search in DTD’s on Windows – Fail!

So you have some DTD files: the main DTD files, model files, and entity files, in a number of folders and sub-folders on Windows XP.

They have extensions as follows:

  • dtd
  • mod
  • ent

Search for something using Windows Explorer, in it’s Search pane. Tell it to search all files and folders. Results? Only from some of the files, not all. Why?

Look at the no-search, no-folders mode of Windows Explorer. It offers to help you view videos, but can’t actually find any to show you. Odd, but related. This is because Windows is aware of a video file type with an extension of “mod”. So it won’t search those files.


Let’s try the command line! You can use “find” to search the contents of files, but only in the current folder.


Fix it with GetGnuWin32! And use grep to find your stuff.

It’s not the “Sound” app, it’s alsamixer

Finally got the sound working on my laptop, running Mint 12 and Cinnamon.

The fix was to go to the Gnome Alsa Mixer and uncheck “External amplifier”. The “Sound” app on the system bar seemed to allow the same change, but it didn’t seem to stick.

I first tried adding more gStreamer plugins. No effect. There were already some gStream plugins installed, but there are lots and lots of others to distract you!

delete .gconfd to fix missing panels

I have had to fix missing panels before in previous versions of Ubuntu and Xubuntu.

Previously, you deleted .gconf from your home directory.

Now you have to delete .gconfd.

“Now” means Xubuntu 10.10.
I am a little out of date on the family computer in the kitchen.

jackd out, sound came back

I have had a real problem with sound on Xubuntu for the last week.

The system says  “Welcome to Xubuntu 9.10” in the web page reached with “Applications > Help”, and “Update Manager” says “11.04” is available, so I think this is the system that was originally installed a s 9.10, and upgraded to 10.04 and 10.10.

There was no way for me to get sound out of this system. Many tweaks and such did not help. Windows runs sound fine.

I looked to see if I installed anything recently, and “Synaptic” said I had installed jackd – way back in October. I uninstalled jackd, and now I can output sound. I am able to record from a USB webcam, but won’t use it.

One thing at a time.

Your daily tools: Tortoise and ls

Gui is cute, and sometimes productive, but GNU command line saved my sanity today.

Tortoise is a good GUI for using Subversion on Windows. It nicely flags all the files with status symbols on their icons.


Sometimes it gets confused when a change is made 2 or more folders deeper, below the one on display. I don’t know whose cache is causing this – Microsoft’s or Tortoise’s, but it’s a minor issue.

It’s been worse since I upgraded to Tortoise 1.7.5. I jumped from 1.6.x to 1.7.5 the other day while writing docs for some tech writers, including how to install Tortoise.

I have several checkouts (OK, working copies) from the same corporate repository, all checked out in C:\svn. (OK, creativity didn’t seem necessary in this case, OK?)

Today the checkout I am most interested in was mostly not displaying its status icons. Yesterday I wasn’t as worried about it. Usually the entire tree was unaccented. Sometimes a folder would light up until I changed something. Then I noticed that all the “.svn” folders were missing, except in the top folder of the tree. Weird. I checked settings on a couple of things to make sure hidden folders were visible. For a while I had a grain of doubt that maybe the .svn folders were really gone.

So I went to the command line. “dir” didn’t see any .svn folders at all. That was because they were “hidden” by a Microsoft flag on them. “dir /ah” showed them, but not any of the other files/folders. Two dir commands required. Painful.

I have GNU Win32 tools installed, which is a port of the regular GNU tools to Windows.

So the answer was “ls -Al”, or “ls -A” for that economical look.

Thanks to all the GNU developers and those who ported and packaged it for Windows. You help me stay sane on the MS platform.

The site to download for Windows is