How to make git stop ignoring your gitignore

When you find that git is ignoring the pattern of specific files in your .gitignore or .git/info/exclude, then it is very likely that the file(s) in question have already been (--force) committed by someone.

Sometimes you just want to ignore changes to your IDE, for instance eclipse project files e.g. .classpath, project.properties, .project. This is what you should do to stop git ignoring your intention to ignore changes to certain files.

1. git update-index --assume-unchanged {filename}

2. echo {filename} >> .git/info/exclude

Step 1. serves to make git stop ignoring your intentions with some {filename}.

Step 2. serves to make locally ignore these files in your own repository, i.e. this ignore directive will not be shared with other people.

Use .gitignore instead of .git/info/exclude in the root of your repository in Step 2. if you want to share this with everybody who has a clone of your repository. Don't forget to add and commit the .gitignore file.

File destroyer / obliterator

I stole the idea here and I wrote a a practical script to embellish on the theme.

#!/bin/sh

#set -e -x
set -e

if [ -f $1 ]; then
  echo "Are you sure? Hit ctrl+c to abort."

  for i in `seq 5`; do
    echo $i && sleep 1;
  done
  # mac osx / bsd: BYTES=$(stat -f%z $1)
  BYTES=$(/usr/bin/du -b $1 | sed 's/\([0-9]\+\).*/\1/')
  /bin/dd if=/dev/urandom of=$1 bs=$BYTES count=1 conv=notrunc
  echo "$1 has been written over with random bits."
  /bin/rm -f $1
  echo "$1 has been removed from the filesystem."
fi

Warning! Achtung baby! Do not use this on sensitive files you may need in the future.

This got me thinking. Imagine you work for a secretive branch of some government and you have sensitive info on your drive you wouldn't want to be caught with dead, like passwords etc. You could build a kill switch for your portable computer(s) with the sensitive files. This kill switch is attached to an artificial pacemaker which senses if you're still alive or not, by checking your heart-beat. This portable computer gets signals from the pacemaker. When it ceases to receive signals, the kill switch is engaged, after 5 minutes with no keep-alive signals from the pacemaker, the portable computer is erased completely.

The trick is to not let the signal get intercepted. Hmmmm... I should write spy-novels with a technical flavour.