Installing Adobe Acrobat Reader on 64-bit Ubuntu 14.04

If you install Adobe Acrobat Reader on recent versions of 64-bit Ubuntu you may see errors like the following:

/opt/Adobe/Reader9/Reader/intellinux/bin/acroread: error while loading shared libraries: libgdk_pixbuf_xlib-2.0.so.0: cannot open shared object file: No such file or directory

This is caused by missing 32-bit libraries. You can install the ones you need as follows:

 sudo apt-get install libgtk2.0-0:i386 libgdk-pixbuf2.0-0:i386

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How to keep individual tracks on your phone with Google Music

Here’s a handy way to save individual songs to your phone or tablet with Google Music so that you can listen off-line:

1. Create a playlist called “Keep”
2. On the playlist view hit the push pin icon (pictured right) to set it to be downloaded and saved to your device
3. Add tracks to your new playlist; they will be automatically downloaded

You can also add songs to the playlist from your desktop and they’ll be downloaded by your device automatically; you can remotely install your favourite music!

How to enable assertions in the Play framework

It took a bit of digging around to figure out how to enable Java assertions for the Play framework, but the answer was simple in the end:

$ export JAVA_OPTS=-ea

This sets the (quasi-standard) JAVA_OPTS environment variable which is incorporated into the SBT launch command.

Truncating strings with bash

This is particularly handy if you’re building up a comma separated list through concatenation and need to remove the final comma. The following snippet removes the final character from $test.

test="Hello world"
echo ${test:0:`expr length "$test" - 1`}

(Cribbed from the Advanced Bash-Scripting Guide.)

Relocating git-svn checkouts

I use git-svn to maintain backups of our entire SVN repository. It’s fast, secure and easy; and the git clone of the whole repository history, branches and all uses about the same space as a subversion needs for a single revision, single branch checkout. No brainer.

Originally we used svn+ssh:// to provide remote SVN access. But as we’ve begun to collaborate with more and more people, we’ve needed to open up subtrees of our repository. And rather than creating user accounts for all these folk we’ve been giving them https:// access. This means that www-data needs to own the repository, so everyone needs to switch over to the new access scheme.

For regular svn checkouts that’s easy enough:

OLD_URL = `svn info; grep URL; cut -d" " -f2`
svn switch --relocate $OLD_URL $NEW_URL

Unfortunately git-svn has no equivalent sub command. Fear not. You could just clone from the new repository location, but that would be horribly wasteful. The following procedure (mainly cribbed from GitWiki) will see you right:

1. Using svn checkout HEAD from the https:// repository. Cache your authentication credentials so git-svn can use them if necessary. This is important.
2. If there haven’t been any commits since your last git-svn rebase make one now e.g. touch kick; svn add kick; svn commit -m "Kicking git-svn". This is important.
3. Now, in your git-svn checkout edit .git/config. In the svn section, comment out the old url entry (hash or semicolon are valid) and add a new one.
4. git-svn fetch to fetch a new revision from the new repository
5. In .git/config comment out the new url entry and restore the old one.
6. git-svn rebase -l to perform a local rebase
7. In .git/config comment out the old url entry and restore the new one.
8. Enjoy the fresh minty taste.