Updating Email ID and Author Name from multiple commits in Git

Multiple Commits:

git filter-branch --commit-filter '
        if [ "$GIT_COMMITTER_NAME" = "" ];
        then
                GIT_COMMITTER_NAME="";
                GIT_AUTHOR_NAME="";
                GIT_COMMITTER_EMAIL="";
                GIT_AUTHOR_EMAIL="";
                git commit-tree "$@";
        else
                git commit-tree "$@";
        fi' HEAD

Single Commit:

To update the author to a specified name [The committer will be set to your configured user in git config user.name and git config user.email]

git commit --amend --author "New Author Name <email@address.com>"

To set both the author and the committer:

git -c user.name="New Author Name" -c user.email=email@address.com commit \
--amend --reset-author

Interactive Rebase

git rebase -i -p <some HEAD before all of your bad commits>

Then mark all of your bad commits as “edit” in the rebase file. If you also want to change your first commit, you have to manually add it as first line in the rebase file (follow the format of the other lines). Then, when git asks you to amend each commit, do

git commit --amend --author "New Author Name <email@address.com>"

edit or just close the editor that opens, and then do

git rebase --continue

to continue the rebase.

You could skip opening the editor altogether here by appending –no-edit so that the command will be:

git commit --amend --author "New Author Name <email@address.com>" --no-edit && \
git rebase --continue

If there are any merge commits between the current HEAD and your , then git rebase will flatten them (if you use GitHub pull requests, there are going to be a ton of merge commits in your history). This can very often lead to very different history (as duplicate changes may be “rebased out”), and in the worst case, it can lead to git rebase asking you to resolve difficult merge conflicts (which were likely already resolved in the merge commits). The solution is to use the -p flag to git rebase, which will preserve the merge structure of your history. The manpage for git rebase warns that using -p and -i can lead to issues, but in the BUGS section it says “Editing commits and rewording their commit messages should work fine.”

Reference:

• https://stackoverflow.com/questions/750172/how-to-change-the-author-and-committer-name-and-e-mail-of-multiple-commits-in-gi/4903673

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Bulk renaming PDFs to their Title names from PDF Metadata

Recently, i realized that I have amassed a huge number of e-books over the years and have ended up dumping them within an e-books directory on my laptop. The problem that I now faced was identifying one book from the other because a lot of them had random filenames based upon where I had downloaded them from.

So I now had a couple of requirements:

1. An automated way of renaming all of these e-books to their actual titles.
2. Removing all duplicate files.

After a little bit of looking around and experimenting around I finally got a Python based solution by Joseph Monaco to my problem. I then forked the orginal repo and added a couple of scripts to it to do my bidding. Now all that I need to do to auto organize all my e-books was this:-

1. git clone https://github.com/sayak-sarkar/pdf-title-rename
2. export PYTHONPATH=${PYTHONPATH}:$(pwd)/xmp.py
3. python pdf-title-rename/pdf-title-rename.py <PATH to my ebooks directory>/*
4. ./remove_duplicate.sh

And voila, all of my e-books were now auto renamed to their titles! 🙂

Come to think about it, I can work on repository a bit more to turn it into a full blown package, but then again, I’m feeling a bit lazy now that my goal’s served! Feel free to send me a Pull Request on GitHub if any of you want to automate it further! 😉

Working around untrusted certificate errors in Express JS

A few very common fatal errors thrown by the request module for express while trying to access data from self-signed web servers are Error: DEPTH_ZERO_SELF_SIGNED_CERT and UNABLE_TO_VERIFY_LEAF_SIGNATURE

This is because of https://github.com/nodejs/node-v0.x-archive/pull/4023 which mandates NodeJS to validate a server’s certificate by default, which needless to say is how things should be in a production environment.

However, more often than none we tend to use self-signed SSL certificates in our development environments or even within internal networks.

Thankfully for such brain-wracking moments, two particular flags come to our rescue. Enter strictSSL and rejectUnauthorized. The way I personally like to use these flags, is to set defaults within my development environments as follows to bypass SSL validation hence, saving the day! 🙂

var request = require('request').defaults({
    strictSSL: false,
    rejectUnauthorized: false
 });

Please do note, that I do not recommend that you ever try this on your production systems without understanding the true implications of what disabling strictSSL and rejectUnauthorized means for you node server. By disabling these, you are essentially telling your server to skip validation of the requested server’s identity, which leaves your application in quite a vulnerable position.

Using Vim to generate HTML output of code

This is an interesting bit that I learnt about from an email in a mailing list by James Pryor.

To generate html output for code within a shell script you can use:

vim myscript.sh '+syntax on' '+ set nu' '+set background=light' +TOhtml '+w myscript.html' '+qall!'

If you don’t want numbers and need a dark background you can use:

vim myscript.sh '+syntax on' '+ set nonu' '+set background=dark' +TOhtml '+w myscript.html' '+qall!'

Installing EditorConfig on Sublime Text

To install Editor Config on Sublime Text all you need to do is to follow the following steps:-

1. Go the Preferences tab -> Package Control.
2. Select Install Package from the drop down menu.
3. Wait for the list to load, once it loads it will show you a list of packages.
4. Now, type in EditorConfig and select the highlighted option.

To confirm that Editor Config is installed correctly on your Sublime Text instance you can go to Preferences -> Browse Packages. If installed correctly you should be able to see an EditorConfig directory present in the Packages directory.

That’s it! Enjoy! 🙂

Installing Sublime Text 3 on RHEL / Fedora

Here’s another three step guide to installing Sublime Text 3 on RHEL 6,7 / Fedora 18, 19, 20:-

1. Download the installation script from the following gist.

   https://gist.github.com/sayak-sarkar/11b039f398ddcae88139

2. Extract it to your home directory [or anywhere you like].

   $tar -xvf gist11b039f398ddcae88139-e339084ef22e956ea6ef8d04f8279ca70772f534.tar.gz

3. Open your terminal (preferably as super user), navigate to your home directory and execute the shell script.

    #./sublime-text-3.sh

Voila!! You now have Sublime Text 3 installed on your machine. You may run it from the terminal or via the alt+f2 shortcut by simply typing in “sublime”.

Based upon my previous post on How to install Sublime Text 3 on Fedora. 😉

Enjoy!! 🙂

Creating scrollable Charts using Angular-Kendo

Creating Scrollable Charts:

Horizontal scrolling of Charts is not supported out of the box in Kendo UI, however it can be achieved using a bit of custom styling.

Basic steps:

• Set overflow: auto of the <div class="chart-wrapper">;
• Set width of the aforementioned div;
• Set width of the <div id="chart"> to a value higher than it’s parent div width size.

Example piece of code:

Template:

<div class="parent-container">
  <div kendo-chart k-options="line" class="chart-container">
  </div>
</div>

CSS:

.parent-container {
    overflow-y: scroll; 
    width: 1000px;
}

.chart-container {
    overflow: auto; 
    width: 2000px;
}

Installing Android on the Geeksphone Keon

Here’s a clean, clear and to the point english post on how to install Android on your Geeksphone Keon developer device:-

STEPS:-

1. If you don’t already have adb and fastboot installed on your system:-
   1. Get the packages from here.
   2. Extract the contents of the zip file and navigate to the adbfastbootmac directory [Note: This package works on macs, if you are using Linux or any other operating system, a simple online search should help you figure out how to get adb and fastboot]
2. On your Keon go to ‘Settings’ -> ‘Device Information’ -> ‘More Information’ -> ‘Developer’. From the list of checkboxes, enable the ‘Remote debugging’ checkbox.
3. Connect your device to your computer using the USB cable.
4. Back on your computer’s terminal do the following:-
   1. If you are using the package mentioned above, run ‘./adb devices’
   2. You should see a device named ‘full_keon’ as a part of the output. If you don’t see it listed out there, try reconnecting your device or check whether the Remote Debugging option is enabled.
5. Now let’s get down to the magic:-
   1. Download and store the following zip packages to you device’s SD-Card:-
      1. TWRP recovery
      2. Android ICS ROM for Keon
      3. Google Apps
      4. Additional Ring Tones
   2. Start the Keon in the fastboot mode :
      # ./adb reboot-bootloader
   3. Install the new recovery :
      # ./fastboot flash recovery TWRP-GK.img
   4. Boot the recovery :
      #./fastboot boot TWRP-GK.img
   5. On the device’s screen now tap on ‘Backup’ to create a backup of Firefox OS.
   6. Once done, tap on ‘Wipe’ → ‘Swipe to Factory Reset’.
   7. ‘Install’ (select the ROM) → ‘Add More Zips’ (select the Google Apps and Additional Ringtones zip files) → ‘Swipe to Confirm Flash’.
   8. ‘Wipe Dalvik and Cache’.
   9. Tap on ‘Reboot System’.
6. Voila! You’ve now successfully installed Android on your Geeksphone Keon device.

NOTES:-

1. Make sure that the device has at least 50% battery power before commencing with the process.
2. Since the Keon has only one soft touch button on it, it is mapped to the back functionality. If you want to use all three default Android soft-buttons, the easiest way to do that would be to install the “SoftKey Enabler” app from the Android Play Store.

SWITCHING BACK TO FIREFOX OS

If you now want to switch back to Firefox OS, all you need to do now is as follows:-

1. Turn off your device.
2. Press the power and the volume up buttons of the Keon at the same time to boot into the Team Win Recovery image.
3. Tap ‘Restore’ and select the backup file created earlier during the Android setup, and confirm.
4. Once the process completes, you should be able to use Firefox OS again! 🙂

DISCLAIMER: Please note that the steps I’ve mentioned here are what I followed to try out Android on a couple of my Keons. These steps involve flashing the device, hence involve a very real risk of ending up with a bricked [dead] phone. As such, go about the process at your own risk. I’m in no way liable for any unforeseen results coming out of this process.

References:

1. http://sys.nodo21.org/geeksphone-keon-rom
2. http://forum.geeksphone.com/index.php?topic=5672.msg60983#msg60983

 

FOSDEM 2014

Ever since the time I first got involved in the Free and Open Source community I would hear about people’s experiences about FOSDEM [Free and Open Source Developers’ European Meeting]. If you are into Open Source communities, then apparently FOSDEM was the place to be. A few years back when I was nothing more than a wide eyed geek attending events out of curiosity to know what the hoopla was all about, I would at times meet people who would talk about someone that they know off, who had been to FOSDEM and I could not help but wonder about how big a tech event can be so big that people would would compare it to the holy grail of FOSS events.

Fast forward a few years, and I got to have a first hand experience of it and that too from the driver’s seat. Not only did I attend FOSDEM this year, but I was also one of the speakers at the Mozilla Dev-Room. I had a joint talk on “Developing Webapps for Firefox OS – The Efficient & Simplistic Approach” with Robert Kaiser (KaiRo).

Me and KaiRo During Our Talk!

In all, this year, four of us [Me, Priyanka, Soumya and Srikar] were invited as speakers at the Mozilla Dev-Room at FOSDEM from India, and it was also the first one for all of us. Even though all four of us are pretty much veteran FOSS evangelists, yet FOSDEM was something that was pretty new to us. Needless to say, we were excited! It was like we were back to being the curious geeky newbie souls that we were just a few years back. And I must say, we enjoyed every moment of the experience to the fullest.

One of the most striking things for me was the fact that for the first time, in the last couple of years I felt nervous while getting on the stage [which, I’m pretty sure was quite evident in my talk]. However, I’m quite sure that it wasn’t peer pressure, or the number of people looking at me in the room [the room was packed with 350+ of the geekiest people from around the world], I’d guess it was more because of the fact that it was something right out of an adolescent day dream for me. Somehow, however, I enjoyed this feeling all over again. I felt like the ever too curious techie geek from a few years back again.

What I do want mention here is after quite a long time [a couple of years maybe?] I went berserk with swag again. I guess being surrounded by the choicest of official goodies representing all the things that you use in your everyday life does have that effect on one. And, I’m pretty sure I wasn’t alone as well. There were people all around me jumping from one booth to the other with the curious glean in their eyes which can easily compete with that of a bookworm left free in the world’s best library without a care in the world. Knowledge flow was the mantra here, and then of course there were the swags.

Swag galore from FOSDEM

I have to confess, I ended up with a pretty good stockpile of stickers and other similar goodies, thanks to my sudden bout of childishness. But again, who can resist the temptation of picking up a few of the most sought after swags in the Free and Open source communities.

I won’t write much about how my talk went though, I would rather leave it for you to see and understand. For the sake of simplicity, I’m embedding the video recording of my talk along with the slides from FOSDEM here. Do check it out and leave me a note, about what you think of it. [Just remember, I was a bit nervous ;)].

Slides: Developing Webapps for Firefox OS – The Efficient & Simplistic Approach

Video: Developing Webapps for Firefox OS – The Efficient & Simplistic Approach

A special note here for Benoit Leseul: You are one of the nicest and wonderful person that I have ever met. Thanks a lot for taking care of us during FOSDEM! 🙂

Coding Best Practices – With a tinge of CSS!

For the curious: What made me write this post:

A very good friend of mine called me up today and asked me to go through a web portal that their company is developing to gather some feedback about it. When I opened the page I was quite impressed at first site and everything about the visual styling to the page layout frankly looked quite awesome.

Being a web developer myself, I somehow couldn’t resist the urge of opening up the browser’s developer tools to check out code behind it, and this is where the problems started showing up. As soon as the developer tools window pane opened up eating up half of my screen estate, I noticed the page layout completely fall apart. There was a mess of overlapping texts, visual elements, and what not all over the page rendering the site completely useless.

By instinct I ended up opening the style editor of developer tools to check the CSS to find out where things where breaking, however what I saw was nothing but plain horror for any front-end developer . It had to be one of the most messed up style-sheets I have ever seen! Basically it was nothing but a garbled up mess of style definitions for classes, ids, media queries, etc. What made it even more insane was that there was no homogeneity to the way the document was written, no indentations and to top it all the whole site had the most generically confusing class names that one could ever have nightmares of.

So, I called up my friend to congratulate him about having such a gem of a front end guy work on his team, when I came to know about the most sorry part of the whole story. The person who wrote this code was apparently a man who had quite a large number of years worth of “industry experience” and has been doing front end work since before even I knew what HTML/CSS was!

This is what convinced me to go ahead and post a few simple things about things that one should keep in mind while writing code with a bit of an inclination towards CSS.

For the Restless, Here’s what I want to say:

Here are a few best practices that I personally follow that I’d like to share with everyone:-

• Always remember that any code that you write has a high probability of being extended or needing maintenance in the long term. 70% of most maintenance woes can be avoided by keeping this simple fact in mind while writing code.
• As a direct consequence of this, make sure that whatever code that you write is readable even to the most novice coders out there.
• Adopt good variable naming practices [eg. a variable name “count” is always more desirable than a variable name “i” for a counter variable since it’s name gives a good idea about it’s functionality.]
• Try and write self documenting code, with enough [read: not too less, yet not too much] comments describing what a certain block of code does, and how it does that. The best way to make sure that the comments are of the perfect length would be to make sure that the comments for a block of around 5-10 lines of code is never longer than 2 lines [of 80 characters each].
• One of the places which very often make the biggest mistakes in documenting stuff are the CSS files. A CSS file with a spaghetti mixture of ids, classes, etc. is never a good idea.
• Always try to have a proper document structure for the CSS with logical grouping of style definitions, preferably with an index comment at the very beginning. This helps make the code more readable and thus much more easy to maintain and extend in the long run.
• Indentation is your biggest friend – It helps make the code more easily readable as well as create a well-structured document format. Indentation makes it dead simple to understand the flow of logic within the program and separated different logical groups from each other by creating well nested content for the document.
• Lastly, and more importantly before signing off a piece of code as ready for production, be honest to yourself and ask yourself: “Is this the kind of code that I would like to read through and work upon in a few years time when I have forgotten the minutes of the implimentation?”

I sincerely this helps atleast a few people to understand what it is like to write beautiful code and give them a brief idea about how to do so themselves.