A byte of Lox

Android and Git: a (version controlled) love story

2013-12-28T00:00:00+00:00

Back in August last year, having a big phone (or phablet as those are called nowadays) was unusual, having a Bluetooth keyboard connected to such a device was seen as weird but wanting to use that combination for writing code and store it in a VCS was considered as borderline.

In those days getting Git up and running on Android wasn’t for the faint of heart as there was no app that dared going any further than supporting read-only operations (i.e. clone and pull) and there was virtually no tutorial, guide or how-to to help in such a quest; that’s when I decided to write what ended up being the most popular piece of text I’ve ever published on the web, i.e. a full length, step by step tutorial on how to get the Git CLI experience working on Android in a Bash shell with the title of “Damngit! Git on Android FTW or how to painfully set up Git on your phone” (which now is nothing more than a redirect to this page).

Due to its popularity and to the set of instructions being a tad out of date, I’ve decided to dust that post and refresh on the topic especially since the apps landscape has changed a bit since then (and there are many more phablet/tablet-equipped developers willing to hack on the go than there used to be back in 2012).

Git apps: what’s available in the store(s)?

So let’s start with a state of the union on what is available today on the Google Play Store in term of both dedicated and git-enabled apps since the “There’s an app for that“ meme is more valid today than ever, there’s a chance you’ll find what you need before investing more time.

The following is a list of apps I played with so far, grouped by category.

GUI clients

Agit is a read-only Git client with a $2.99 price tag; it has a lot of limitations dictated by the version of JGit being used (e.g. no support for symlinks and submodules, very slow at cloning big repositories) although it offers a couple features not found in any other app, i.e. periodic sync (it fetches the list of commits every 15 minutes) and animated diffs
Git is a very basic, read-only, free client open sourced under GPLv3 (which is its only virtue for now), at the time of writing it is a decent repository browser
CubeGit is probably the best commercial Git client on Android, it comes in at $1.60 but has many valuable features (e.g. generating SSH keys and support for push of course) and it leverages native binaries (i.e. it’s fast)
SGit is a full-fledged Git client under active development; it’s free, open sourced under GPLv3 and apart from allowing to push to a repository it also supports merging branches, importing existing local repositories and cherry-picking commits, all wrapped in a functional UI (especially if compared to other apps in the same category)

My pick in this category is SGit.

Git-enabled IDEs and Editors

AIDE is a fully backed IDE for Android development in Java and C++ (NDK), it could be easily labeled as “Eclipse in a pocket” (it can actually import Eclipse projects!); the free version includes read-only git support, being able to commit, branch and push will cost you $6.99 and there’s also a version targeted at PhoneGap development (that will cost you twice as much)
DroidEdit is a glorified programmer’s editor with support for many languages, git integration is available only in the paid version that comes with a $2 price tag and supports pushing code to remotes

I’m a happy DroidEdit user which is also what I use as a note-taking “cloud” app on my phone after I abandoned Evernote and SimpleNote in favor of a private git repository hosted at BitBucket filled with an organized collection of markdown text files, but that’s material for another post.

CLI environments

ZShaolin is a fully featured, GNU-powered ZSH environment; while it is an open source project that comes packaged with the git, ssh and rsync binaries among many others (Lighthttpd! Emacs!!), getting it to run on your device without the need of compiling it yourself will cost $3.25
Terminal IDE predates and inspired ZShaolin, it’s a free and open source Bash environment which also offers git, the name refers to it’s original goal of delivering a Vim setup targeted at Java development on Android; also, it only support git over SSH for remotes

I have to admit ZShaolin is a very attractive package and while Terminal IDE needs a bit of tweaking to get Git to work correctly with remotes, my preference goes to the latter as easy access to tools that have been in the public domain for over 30 years should be free on any platform and also because I have a mild preference for Bash over ZSH.

So, if you haven’t found and IDE, Editor or GUI client that satisfies your VCS needs while going through the lists above and for whatever reason ZShaolin is not your cup of tea then fear not and hold tight as we’ll go through the steps to set up Terminal IDE’s Git tool-chain to work as expected.

Setting up Terminal IDE for Git work-flows

Follow this steps to get through a spiral of painful joy and be able to successfully run git push against your remotes and call yourself a victor:

The obvious, we need to get Terminal IDE installed on our devices
Since there’s only support for SSH, we’ll also need a pair of private/public RSA keys
- You can generate those on any machine that can run ssh-keygen and then move it to /data/data/com.spartacusrex.spartacuside/files/.ssh (which could be a bit tricky depending on your understanding of Android’s sandboxed file system for apps’ data)
- You can generate the keys using dropbearkey directly in Terminal IDE’s prompt: bash mkdir ~/.ssh dropbearkey -t rsa -f ~/.ssh/id_rsa This will create a passphrase-less pair of keys fitting our Git needs and print out the public token (you can retrieve it at any time by running dropbearkey -y -f ~/.ssh/id_rsa)
We’ll have to deploy the public key on the remote(s), this varies depending on your remote, e.g. on GitHub this can be done through the user settings page
Now that we have keys we need to tell SSH and Git to use the correct identity, you can use either vim or nano as the shell supports both
1. Create a script for Git to use the identity, e.g. nano ~/local/bin/ssh-git bash #!/data/data/com.spartacusrex.spartacuside/files/system/bin/bash exec ssh -i ~/.ssh/id_rsa "$@"
2. Make the script executable by running chmod +x ~/local/bin/ssh-git
3. Edit the .bashrc settings file that comes with Terminal IDE, e.g. nano ~/.bashrc: bash export GIT_SSH=~/local/bin/ssh-git
4. Shutdown and re-start Terminal IDE
Now we need to associate a Git user to the identity, unfortunately the version of git bundled with Terminal IDE has issues with reading user name and email from config files set via the git config command so we’ll have to resort to a different method
1. Edit .bashrc once again and add the following bash export GIT_AUTHOR_NAME="USER NAME" export GIT_AUTHOR_EMAIL="user@email.address" export GIT_COMMITTER_NAME=$GIT_AUTHOR_NAME export GIT_COMMITTER_EMAIL=$GIT_AUTHOR_EMAIL If your remote is GitHub make sure the user name and email match the ones used for your GitHub user
2. Shutdown and re-start Terminal IDE

If you got so far to read this line, then congratz! You can start using your pocket-able Git setup!

To save any remain of sanity I’d suggest you get an USB OTG or Bluetooth keyboard, the soft keyboard that comes with Terminal IDE is ok but nothing can replace a physical keyboard when coding/hacking.

Happy Git-ing!

Tabs, stop! The truth about tab and spaces in Vim

2013-04-01T00:00:00+00:00

I’m one of those Jurassic reptiles that enjoys using Vim; don’t ask, just let me be and in case you feel like spending a weekend with me and my pack of laser-eyed tamed T-Rex’s playing with keyboard shortcuts just have a look at the ad-hoc collection of resources I collected over time and/or at my vimrc settings.

Now Vim, being a neat piece of software developed by smart people, has no less than 4 settings related to code indentation with pretty similar names just to make things easier; so far I managed surviving by teaching to the aforementioned T-Rex collective to leave comments in my vimrc to remind me why each of those 4 settings in being used, until I realized moving that arcane knowledge to a more reliable destination was a better idea, hence this post.

Bear with me if you want to learn everything about the magic world of indentation in Vim!

We’ll walk through each setting connected to indentation in detail to understand what each does and how it works together with his siblings.

tabstop

This setting tells Vim how many columns a tab should be made up of in the editor view, it takes care only of how tabs will be rendered and has no effect on the actual text.

expandtab and noexpandtab

Enabling this option via the set command will insert the appropriate number of spaces when in insert mode.

shiftwidth

Set a value for this option to control how many columns text will be indented when using indent operations (such as << or >>) in normal or visual mode; this also covers automatic C-style indentation.

softtabstop

This option results in different behaviours depending on its own value and the one set for tabstop and the status of the expandtab toggle:

softtabstop < tabstop, noexpandtab - This will result in a combination of tabs and spaces to make up the total spacing
softtabstop == tabstop, noexpandtab - This will always force the use of tabs
expandtab - The value of softtabstop will be ignored and spaces will be forced

Examples

So here’s an example of how to use all of the above in your vimrc file or in ftplugin resources:

" Example of typical indentation for Python code, i.e. 4 spaces
set expandtab
set tabstop=4
set shiftwidth=4

You can also set those values on depending on the file type directly in vimrc:

autocmd FileType ruby setlocal expandtab tabstop=2 shiftwidth=2 softtabstop=2

If you’re insane enough to feel like learning even more about indentation in Vim, I’d suggest going through the reference material put together by Ted Logan.

Happy indenting!

SEO: FTW

2011-04-14T00:00:00+00:00

April 14th at 13:30 I’ll give a lecture about the basics of Search Engine Optimization (a.k.a. SEO), is going to be a lot of fun!

The event is sponsored by Wikia and will be hosted by Poznan University of Technology, if you won’t be able to join you can still go through the the slides deck.

DISCLAIMER: those slides are meant to be accompanied by a voice commentary that describes and explains in detail each concept/idea/picture/joke, soon I’ll release a “standalone” set of slides with the speaker’s notes at robimy.wikia.com later on.

Update 14th Apr 2011: The lecture went pretty smooth, people didn’t fall asleep (thanks to a good dose of jokes), got some good ratings/comments and some tips to improve the slides; I’m actually planning to do it once again, different target next time.

Update 18th Apr 2011: I’ve reworked the slides deck, they now come also with a full transcript.