ILUG Bengaluru Meetup - Saturday 21st February 2009

Linux User Group, Bangalore have a meetup at the ThoughtWorks office on Saturday 21st February 2009, 4:30 PM onwards. The details of the meeting are here. There are 2 talks lined up- "Introduction to the Android Platform" and "Device Mapper - How it works and why you should be using it". And there will be a key signing party as well.

Go, check it out and help revive the LUG meetings at Bangalore.

Contributing to a Project with a Maintainer Who Doesn't Merge Contributions Quickly

I saw this mail in one of the mailing lists I am on and thought it might be useful to a wider audience. This reply was given by Ben Finney

   I have some ambitious plans for enhancing the module, but I feel
   that it won't be practical to do it in the current conditions. I
   tried to soft-talk the maintainer into giving me repository access,
   but then the conversation got diverted into applying my latest
   patch, which he said he'd like to perform the next day. He didn't
   and it's been at least two weeks since then.

Since you talk about asking for “commit access”, I presume it's in an old-school centralised-only VCS. I'll assume Subversion.

What are your thoughts about a situation like this?

Use a distributed VCS to track your changes. I prefer Bazaar, so I'll discuss that below.

• Use Debian GNU/Linux, ‘lenny’ or later.
• Install the necessary packages: $ sudo aptitude install bzr bzrtools bzr-svn svn
• Get a local Bazaar checkout of the upstream Subversion branch so you can track upstream's changes discretely and easily: $ bzr checkout svn+ssh://vcs.example.org/foo/trunk/ foo.trunk/
• Bazaar uses the ‘bzr-svn’ plugin to work with Subversion repositories. It has its foibles, especially with writing to Subversion repositories; but for tracking an upstream Subversion repository against your Bazaar-managed branches, it's excellent.
• Branch from upstream so you can track your changes: $ bzr branch foo.trunk/ foo.interesting-new-feature/
• Work on your interesting new feature, committing often:

    $ cd foo.interesting-new-feature/
    $ emacs spam.py  # hack hack hack
    $ make test  # or however you run your full test suite
    $ bzr commit --message "One-line description"

• When upstream has new revisions in their repository, update your checkout:

    $ cd foo.trunk/
    $ bzr update

• When you want to send a patch of your current work against upstream, generate a Bazaar “merge directive” (a patch bundle):

    $ cd foo.interesting-new-feature/
    $ bzr send --output ../foo.interesting-new-feature.patch --no-bundle

• This makes a patch against the parent of the current branch (by default, since no other branch is specified), which is the ?foo.trunk/? branch you originally branched from. The --no-bundle option turns off the ?patch bundle? blob, which would be useful to a Bazaar-using remote user to merge the resulting patch and have identical revisions to you. Since you'll be sending it to a Subversion user, that blob won't be useful to them so we disable it.
• Send the ‘foo.interesting-new-feature.patch’ file to upstream attached to an email message that explains what the changes are.

The Bazaar documentation, both online at <http://bazaar-vcs.org/> and in the bzr help foo commands, is comprehensive and should fill the many gaps I've no doubt left from the above explanation.

egrep - searching for more than one pattern at a time

Thanks to egrep for linguists for giving this nice and clear example of using egrep.

There are different ways to match both star and stars within a single search pattern. The most straightforward way might be to tell egrep to look for either the string star or the string stars with the help of a disjunction, expressed with the vertical bar, |. This time the search pattern has to be quoted in order for the program to know where the search pattern starts and ends

    $ egrep -w 'star|stars' sonnets.txt
    Not from the stars do I my judgement pluck,
    And constant stars in them I read such art
    Whereon the stars in secret influence comment.
    Let those who are in favour with their stars,
    Till whatsoever star that guides my moving,