Preserving your working directory in gnome-terminal

I use gnome-terminal for most of my hacking. In fact, I use it so much, that I’ll often have multiple tabs open for a particular project. Here’s my workflow:

1. Control+Alt+t (My shortcut to open a new gnome-terminal window.)
2. cd ~/code/some_cool_hack/ # directory of some cool hack
3. Control-Shift-t (Shortcut to open a new gnome-terminal tab.)
4. Hack, hack, hack…

The problem is that the new tab that I’ve created will have a $PWD of ~, instead of keeping the $PWD of ~/code/some_cool_hack/, which is the project I’m working on!

The solution is to add:

# including this ensures that new gnome-terminal tabs keep the parent `pwd` !
if [ -e /etc/profile.d/vte.sh ]; then
    . /etc/profile.d/vte.sh
fi

to your ~/.bashrc. Now everything works perfectly!

Many thanks to Matthias Clasen and Ray Strode for figuring this one out!

One side note: this used to be the default, but for some reason it broke around Fedora 19 or 20. Maybe it had to do with my fancy prompt, but everything is working great now.

Happy Hacking,

James

 

Desktop Notifications for Irssi in Screen through SSH in Gnome Terminal

I’m usually on IRC, but I don’t often notice incoming pings until after the fact. I had to both write, and modify various scripts to get what I wanted, but now it’s all done, and you can benefit from my hacking by following along…

The Setup

Laptop -> Gnome-Terminal -> SSH -> Screen -> Irssi

This way, I’m connected to IRC, even when my laptop isn’t. I run irssi in a screen session on an SSH server that I manage, and I use gnome-terminal on my laptop. If you don’t understand this setup, then you’ll need to get more comfortable with these tools first.

Fnotify

The first trick is getting irssi to store notifications in a uniform way. To do this, I modified an irssi script called fnotify. My changed version is available here. Installation is easy:

# on your ssh server:
cd /tmp; wget https://dl.dropboxusercontent.com/u/48553683/irssi/fnotify.pl
cp /tmp/fnotify.pl ~/.irssi/scripts/
# in irssi:
irssi> /load perl
irssi> /script load fnotify

When someone sends you a direct message, or highlights your nick on IRC, this script will append a line to the ~/.irssi/fnotify file on the SSH server.

Watching fnotify

On your local machine, we need a script to tail the fnotify file. This was surprisingly hard to get right. The fruit of my labour is available here. You’ll want to copy this script to your local ~/bin/ directory. I’ve named this script irssi-fnotify.sh. This script watches the remote fnotify file, and runs notify-send and paplay locally to notify you of any incoming messages, each time one comes in.

SSH Activation

We want the irssi-fnotify.sh script to run automatically when we connect to our SSH server. To do this, add the following lines to your ~/.ssh/config file:

# home
Host home
    HostName home.example.com
    PermitLocalCommand yes
    LocalCommand ~/bin/irssi-fnotify.sh --start %r@%h

You might also want to have other directives listed here as well, but that is outside the scope of this article. Now each time you run:

ssh home

The irssi-fnotify.sh command will automatically run.

Magic

I’ve left out some important details:

• The LocalCommand that you use, must return before ssh will continue. As a result, it daemonizes itself into the background when you invoke it with –start.
• My irssi-fnotify.sh program watches the parent ssh $PID. When it exits, it will run a cleanup routine to purge old notifications from the fnotify file. This requires a brief SSH connection back to the server. This is a useful feature!
• You may wish to modify irssi-fnotify.sh to paplay a different alert sound, or to avoid making noise entirely. The choice is yours.
• When irssi-fnotify.sh runs, it will tail the fnotify file over ssh. If there are “unread” messages, tail will try to “download” up to ten. You can edit this behaviour in irssi-fnotify.sh if you want a larger initial backlog.
• The irssi-notify.sh script doesn’t attempt to prevent flooding, nor does it filter weird characters from incoming messages. You may want to add this yourself, and or /kb users who cause you to need these features.

Here’s a little screenshot (with shameless plug) of the result in action:

Here’s an example of how this helps me to be more responsive in channel:

helping out in #gluster

I hope you found this useful.

Happy Hacking,

James

GNOME Montreal Summit

This October 12th to 14th Montreal hosted the GNOME boston summit. Many thanks to Canonical for sponsoring breakfast, Savoir Faire Linux for hosting a great 6 à 10 with fancy snacks, and RedHat for sponsoring a pool night. What follows is some technical commentary about stuff that went on.

JHBuild

JHBuild is a tool to make it easy to download/clone (from git) and compile all the GNOME modules and applications. It was easy to get going. I (mostly) followed the steps listed on the JHBuild HowDoI wiki page. I kept my .jhbuildrc in my home directory instead of ~/.config/. On my Fedora 19 machine, I found certain unlisted dependencies were missing to build everything. You can figure these out yourself when your builds fail, or just run the following command to install them beforehand:

# yum install /usr/bin/{g++,a2x,gnome-doc-prepare} python-rdflib lua-devel

The abridged list of commands that I ran includes:

$ git clone git://git.gnome.org/jhbuild
$ ./autogen.sh --simple-install
$ make
$ make install
$ ln -s ~/.local/bin/jhbuild ~/bin/jhbuild
$ jhbuild sysdeps --install
$ jhbuild buildone gnome-themes-standard    # i was impatient to get this early
$ jhbuild update                            # at home on fast network
$ jhbuild build --no-network                # can be run offline if you like
$ jhbuild run gedit
$ jhbuild shell                             # then run `env` inside the shell

You want to properly understand the context and working directory for each of these, but it should help get you to understand the process more quickly. One thing to realize is that the jhbuild run actually just runs a command from your $PATH, but from within the jhbuild environment, with modified $PATH and prefix variables. Run:

$ jhbuild run env

to get a better understanding of what changes. When patching, I recommend you clone locally from the mirrored git clones into your personal ~/code/ hacking directory. This way JHBuild can continue to do its thing, and keep the checkouts at master without your changes breaking the process.

Boxes

Boxes is a simple virtual machine manager for the GNOME desktop.

Zeeshan talked about some of the work he’s been doing in boxes. William Jon McCann reviewed some of the UI bugs, and I proposed the idea of integrating puppet modules so that a user could pick a module, and have a test environment running in minutes. This could be a way for users to try GlusterFS or FreeIPA.

GNOME Continuous

GNOME continuous (formerly known as GNOME-OSTree) is a project by Colin Walters. It is amazing for two reasons in particular:

1. It does continuous integration testing on a running OS image built from GNOME git master. This has enabled Colin to catch when commits break apps. It even takes screenshots so that you see what the running apps look like.
2. It provides bootable GNOME images that you can run locally in a vm. The images are built from GNOME git master. While there are no security updates, and this is not recommended for normal use, it is a great way to test out the bleeding edge of GNOME and report bugs early. It comes with an atomic upgrade method to keep your image up to date with the latest commits.

My goal is to try to run the bootable image for an hour every month. This way, I’ll be able to catch GNOME bugs early before they trickle down into Fedora and other GNOME releases.

Abiword 3.0

Hubert Figuière released AbiWord 3.0 which supports GTK+ 3. Cool.

A11y

Some of the A11y team was present and hacking away. I learned more about how the accessibility tools are used. This is an important technology even if you aren’t using them at the moment. With age, and accident, the current A11y technologies might one day be useful to you!

Hacking Hearts

Karen Sandler was kind enough to tell me about her heart condition and the proprietary software inside of her pacemaker defibrillator. Hopefully hackers can convince manufacturers that we need to have access to the source.

Yorba and Geary

Jim Nelson is a captivating conversationalist, and it was kind of him to tell me about his work on Geary and Vala, and to listen to my ideas about GPG support in email clients. I look forward to seeing Geary’s future. I also learned a bit more about IMAP.

Future?

I had a great time at the summit, and it was a pleasure to meet and hangout with the GNOME hackers. You’re always welcome in Montreal, and I hope you come back soon.

Happy Hacking,

James

Installing missing GNOME games

I just realized that my Fedora 19 installation didn’t have any of the GNOME games installed by default any more. I guess there’s no love for nibbles. Here’s a quick one-liner to get them all back:

$ sudo yum search game | grep gnome | awk '{print $1}' | xargs sudo yum install -y
Loaded plugins: etckeeper, langpacks, refresh-packagekit
Package gnome-nibbles-3.8.0-2.fc19.x86_64 already installed and latest version
Resolving Dependencies
--> Running transaction check
---> Package gnome-chess.x86_64 0:3.8.3-2.fc19 will be installed
--> Processing Dependency: gnuchess for package: gnome-chess-3.8.3-2.fc19.x86_64
---> Package gnome-hearts.x86_64 0:0.3-12.fc19 will be installed
---> Package gnome-klotski.x86_64 0:3.8.2-2.fc19 will be installed
---> Package gnome-mahjongg.x86_64 0:3.8.0-3.fc19 will be installed
---> Package gnome-mines.x86_64 0:3.8.1-3.fc19 will be installed
---> Package gnome-robots.x86_64 0:3.8.1-3.fc19 will be installed
---> Package gnome-sudoku.noarch 1:3.8.1-3.fc19 will be installed
---> Package gnome-tetravex.x86_64 0:3.8.1-2.fc19 will be installed
--> Running transaction check
---> Package gnuchess.x86_64 0:6.0.3-1.fc19 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

================================================================================
 Package               Arch          Version                Repository     Size
================================================================================
Installing:
 gnome-chess           x86_64        3.8.3-2.fc19           fedora        2.6 M
 gnome-hearts          x86_64        0.3-12.fc19            fedora        365 k
 gnome-klotski         x86_64        3.8.2-2.fc19           fedora        1.2 M
 gnome-mahjongg        x86_64        3.8.0-3.fc19           fedora        3.8 M
 gnome-mines           x86_64        3.8.1-3.fc19           fedora        2.7 M
 gnome-robots          x86_64        3.8.1-3.fc19           fedora        1.4 M
 gnome-sudoku          noarch        1:3.8.1-3.fc19         fedora        2.5 M
 gnome-tetravex        x86_64        3.8.1-2.fc19           fedora        1.7 M
Installing for dependencies:
 gnuchess              x86_64        6.0.3-1.fc19           fedora        2.6 M

Transaction Summary
================================================================================
Install  8 Packages (+1 Dependent package)

Total download size: 19 M
Installed size: 54 M
Downloading packages:
(1/9): gnome-chess-3.8.3-2.fc19.x86_64.rpm                 | 2.6 MB   00:04     
(2/9): gnome-mines-3.8.1-3.fc19.x86_64.rpm                 | 2.7 MB   00:05     
(3/9): gnome-klotski-3.8.2-2.fc19.x86_64.rpm               | 1.2 MB   00:05     
(4/9): gnome-robots-3.8.1-3.fc19.x86_64.rpm                | 1.4 MB   00:01     
(5/9): gnome-tetravex-3.8.1-2.fc19.x86_64.rpm                                                                                          | 1.7 MB  00:00:03     
(6/9): gnome-hearts-0.3-12.fc19.x86_64.rpm                                                                                             | 365 kB  00:00:10     
(7/9): gnuchess-6.0.3-1.fc19.x86_64.rpm                                                                                                | 2.6 MB  00:00:04     
(8/9): gnome-mahjongg-3.8.0-3.fc19.x86_64.rpm                                                                                          | 3.8 MB  00:00:11     
(9/9): gnome-sudoku-3.8.1-3.fc19.noarch.rpm                                                                                            | 2.5 MB  00:00:06     
--------------------------------------------------------------------------------------------------------------------------------------------------------------
Total                                                                                                                         1.5 MB/s |  19 MB     00:12     
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
etckeeper: pre transaction commit
  Installing : gnuchess-6.0.3-1.fc19.x86_64                                                                                                               1/9 
  Installing : gnome-chess-3.8.3-2.fc19.x86_64                                                                                                            2/9 
  Installing : gnome-klotski-3.8.2-2.fc19.x86_64                                                                                                          3/9 
  Installing : gnome-tetravex-3.8.1-2.fc19.x86_64                                                                                                         4/9 
  Installing : gnome-mines-3.8.1-3.fc19.x86_64                                                                                                            5/9 
  Installing : 1:gnome-sudoku-3.8.1-3.fc19.noarch                                                                                                         6/9 
  Installing : gnome-hearts-0.3-12.fc19.x86_64                                                                                                            7/9 
  Installing : gnome-mahjongg-3.8.0-3.fc19.x86_64                                                                                                         8/9 
  Installing : gnome-robots-3.8.1-3.fc19.x86_64                                                                                                           9/9 
etckeeper: post transaction commit
  Verifying  : gnome-chess-3.8.3-2.fc19.x86_64                                                                                                            1/9 
  Verifying  : gnuchess-6.0.3-1.fc19.x86_64                                                                                                               2/9 
  Verifying  : gnome-robots-3.8.1-3.fc19.x86_64                                                                                                           3/9 
  Verifying  : gnome-mahjongg-3.8.0-3.fc19.x86_64                                                                                                         4/9 
  Verifying  : gnome-hearts-0.3-12.fc19.x86_64                                                                                                            5/9 
  Verifying  : 1:gnome-sudoku-3.8.1-3.fc19.noarch                                                                                                         6/9 
  Verifying  : gnome-mines-3.8.1-3.fc19.x86_64                                                                                                            7/9 
  Verifying  : gnome-tetravex-3.8.1-2.fc19.x86_64                                                                                                         8/9 
  Verifying  : gnome-klotski-3.8.2-2.fc19.x86_64                                                                                                          9/9 

Installed:
  gnome-chess.x86_64 0:3.8.3-2.fc19    gnome-hearts.x86_64 0:0.3-12.fc19     gnome-klotski.x86_64 0:3.8.2-2.fc19    gnome-mahjongg.x86_64 0:3.8.0-3.fc19   
  gnome-mines.x86_64 0:3.8.1-3.fc19    gnome-robots.x86_64 0:3.8.1-3.fc19    gnome-sudoku.noarch 1:3.8.1-3.fc19     gnome-tetravex.x86_64 0:3.8.1-2.fc19   

Dependency Installed:
  gnuchess.x86_64 0:6.0.3-1.fc19                                                                                                                              

Complete!
$

This isn’t a master hack, but it’s good to think about using command line magic to do your day-to-day tasks.

Happy gaming,

James

PS: I also updated the blog’s theme. Let me know if you hate it.

Upgrading from Fedora 18 to Fedora 19

It was time to take the plunge and upgrade from Fedora 18 to Fedora 19. Fedora 18 was one of the worst releases ever, so I figured it could only get better. I ran my backups as usual, however this time I didn’t seem to need them, the upgrade process went off without a hitch! I used the fedup-cli process over the network. I always run these things inside of screen.

Here are my post install notes and comments:

Brown folder icons:

Someone broke the icon theme, and folders are now an ugly brown. Even though you’ll see a “Fedora” entry in the GNOME tweak tool, icon theme section, it won’t work. You need to install a theme package first:

# yum install fedora-icon-theme

tweak tool will now let you fix the brown icon issue.

Dash doesn’t launch new windows:

The GNOME shell is back to its old habit of trying to imitate Mac OSX. Thankfully there’s an official extension to fix this: https://extensions.gnome.org/extension/600/launch-new-instance/

If you search for “Classic Mode” on https://extensions.gnome.org/ you’ll find some other useful add ons. You might enjoy: AlternateTab, AvoidOverview, and SystemMonitor.

Evolution is snappier:

Congratulations to the evolution developers, this release seems a bit snappier! I haven’t tested it thoroughly, however closing evolution now happens in under ten seconds! Usually it would either hang or take much longer to close. Keep up the good work!

Clocks deletes your old clocks:

The clocks application deleted all the clocks that I had added. I suppose there are worse forms of data loss, but this is still pretty unprofessional! I had added one for every new place I had visited. Goodbye memories!

YUM breaks pexpect scripts:

A new version of YUM, now prompts you differently:

# yum install foobar[...]
Is this ok [y/d/N]:

No it’s not okay that you’re confusing my brain by adding a d. I actually don’t have any pexpect scripts depending on this, but after years of seeing y/N, the change is not welcomed. It should have been handled with a YUM download target instead.

Password prompts are annoying:

The GNOME shell handles most of the password prompts. This makes sense because it can help prevent you typing your password into a chat room. The problem is that if you need to run an external password manager to find a password, you’re out of luck. Maybe someone can add an option to minimize the focus stealing window. In addition, the “remember password” checkbox should NOT be on by default! It still is for evolution, and perhaps other apps too.

GNOME shell isn’t smooth, but it’s better:

Fedora 17 provided a smooth GNOME shell experience. Fedora 18, somehow killed the performance, and no fixes could be found. The performance seems to be a bit better in Fedora 19, but it’s still not perfect. Drivers are probably partly to blame.

New version of Gedit breaks some things:

The Gedit dashboard plugin no longer seems to work. After debugging the issue, it seems to be a packaging problem. To fix:

# yum install python3-dbus

and dashboard should work when enabled. The gedit-autotab plugin is thoroughly broken. I’d love to get that working again for smarter spaces!

That’s all for now,

Happy hacking,

James

 

a puppet-ipa user type and a new difference engine

A simple hack to add a user type to my puppet-ipa module turned out to cause quite a stir. I’ve just pushed these changes out for your testing:

3 files changed, 1401 insertions(+), 215 deletions(-)

You should now have a highly capable user type, along with some quick examples.

I’ve also done a rewrite of the difference engine, so that it is cleaner and more robust. It now uses function decorators and individual function comparators to help wrangle the data into easily comparable forms. This should make adding future types easier, and less error prone. If you’re not comfortable with ruby, that’s okay, because it’s written in python!

Have a look at the commit message, and please test this code and let me know how it goes.

Happy hacking,

James

PS: This update also adds server configuration globals management which you may find useful. Not all keys are supported, but all the framework and placeholders have been added.

 

Forcing firefox to remember passwords

There are a handful of websites out there that decide that they know better than your browser and tell it to not offer to save passwords. They do this by setting a form autocomplete attribute to off.

Since we already agree that HTML and the web are a terrible idea, hopefully we can find a way to hack around this. It turns out that I didn’t have to, because many others have solved this hack before me. The cleanest version I found is here: http://www.howtogeek.com/62980/how-to-force-your-browser-to-remember-passwords/

It’s not that complicated actually, a little bookmarklet (javascript code, stored in a bookmark, and activated when you open it) is saved in your browser, and on activation, it loops through all the page’s forms and turns on the autocomplete off‘s.

I’ve copied the code here, in the interests of archiving this very useful hack. Here you go:

Shortened form:

javascript:(function(){var%20ac,c,f,fa,fe,fea,x,y,z;ac="autocomplete";c=0;f=document.forms;for(x=0;x<f.length;x++){fa=f[x].attributes;for(y=0;y<fa.length;y++){if(fa[y].name.toLowerCase()==ac){fa[y].value="on";c++;}}fe=f[x].elements;for(y=0;y<fe.length;y++){fea=fe[y].attributes;for(z=0;z<fea.length;z++){if(fea[z].name.toLowerCase()==ac){fea[z].value="on";c++;}}}}alert("Enabled%20'"+ac+"'%20on%20"+c+"%20objects.");})();

Long form:

function() {
   var ac, c, f, fa, fe, fea, x, y, z;
   //ac = autocomplete constant (attribute to search for)
   //c = count of the number of times the autocomplete constant was found
   //f = all forms on the current page
   //fa = attibutes in the current form
   //fe = elements in the current form
   //fea = attibutes in the current form element
   //x,y,z = loop variables

   ac = "autocomplete";
   c = 0;
   f = document.forms;

   //cycle through each form
   for(x = 0; x < f.length; x++) {
      fa = f[x].attributes;
      //cycle through each attribute in the form
      for(y = 0; y < fa.length; y++) {
         //check for autocomplete in the form attribute
         if(fa[y].name.toLowerCase() == ac) {
            fa[y].value = "on";
            c++;
         }
      }

      fe = f[x].elements;
      //cycle through each element in the form
      for(y = 0; y < fe.length; y++) {
         fea = fe[y].attributes;
         //cycle through each attribute in the element
         for(z = 0; z < fea.length; z++) {
            //check for autocomplete in the element attribute
            if(fea[z].name.toLowerCase() == ac) {
               fea[z].value = "on";
               c++;
            }
         }
      }
   }

   alert("Enabled '" + ac + "' on " + c + " objects.");
}

Happy hacking,

James

PS: Best friends forever if you can get firefox to natively integrate with the gnome-keyring. No I don’t want to force it to myself, get this code merged upstream please!

Mothers day hacks

Firstly Happy Mother’s day to my mother.

Google is, as usual, busily releasing doodles. Today, the doodle takes you through a Rube Goldberg -esque sequence, giving you four decisions to make along the way. Each decision gives you one of three different choices, and at the end, a unique drawing is displayed. I expect:

3 * 3 * 3 * 3 = 81

different permutations. At the end of the process, you can print your image. I got directed to:

https://www.google.ca/logos/2013/mom/print/3311.html

which suspiciously has a four digit filename composed of three’s and ones. Inspecting the file in firefox shows that the main image url is:

https://www.google.ca/logos/2013/mom/hdcards/3311.jpg

with a similarly suspicious “3311“. I decided that I wanted to see all the permutations without having to refresh google’s page. Jumping to a terminal, and using some bash expansion magic:

$ cd /tmp
$ mkdir hack1
$ cd hack1/
$ wget https://www.google.ca/logos/2013/mom/hdcards/{1..3}{1..3}{1..3}{1..3}.jpg
[snip]
FINISHED --2013-05-12 07:07:22--
Total wall clock time: 1m 23s
Downloaded: 81 files, 138M in 1m 19s (1.75 MB/s)

I am pleased to see that 81 files have downloaded, and that they’re all unique:

$ md5sum * | sort | uniq | wc -l
81

and all png’s:

$ file * | awk '{print $2}' | sort | uniq | wc -l
1
$ file * | head -1
1111.jpg: JPEG image data, EXIF standard

Now I can very easily browse through the images with eog, and select my favourite.

Hope this has been instructive,

Happy hacking,

James

 

Fixing jerky scrolling in Firefox

Fedora did a lovely job of updating me to the latest version (v. 20) of Firefox. One problem I found, was that scrolling on certain pages was quite jerky. Performance was worse (or more likely) on pages with a frameset, and pages which were long. Pages with many images made this problem worse.

It turns out that the workaround is to disable hardware acceleration:

After you’ve unchecked this box, restart Firefox, and scrolling is now considerably smoother.

Hopefully this helped you out. Most likely there is some driver issue or deficiency with the X drivers. I’m using an excellent Thinkpad X201. I’ve also had at least two cases of X freezing while I was manipulating a Firefox window, so perhaps this is related, and hopefully this won’t happen to me anymore.

Happy hacking,

James

 

Knowing when to release and deploy your code (…and a mini script)

Knowing when to release and deploy your code can turn into a complicated discussion. In general, In general, I tend to support releasing early and often, for some value of $early and $often. I’ve decided to keep this simple and introduce you to one metric that I use…

I think that I am fairly diligent in adding plenty of comments to my source code. I might even sometimes add too many. I create plenty of XXX, FIXME, or TODO tagged comments as reminders of things to work on.

To me, XXX represents an important problem that should get looked at or fixed; FIXME, reminds me that I should definitely look into something, and finally, TODO gives me homework or things to pursue when I’m in need of a new project.

I try to resolve most if not all XXX tagged comments before making a 0.1 release, FIXME’s to consider something very stable, and a lack of TODO’s mean something is completely done for now.

To count all these, I wrote a little tool that greps through the top-level directories in my ~/code/ folder, and displays the results in a table. Feel free to give it a try, and use it for your own projects.

While I don’t see this as a particularly game changing utility, it scratches my itch, and helps me keep up my bash skills. The code is available here. Let me know if you have any improvements, or if the source isn’t enough documentation for you.

Happy hacking,

James