Automatically increment bugfix version in a version file within the code. Create a version file if non exists. This is to have a version reference separate from git branching.

pre-commit.sh

#!/bin/bash
# This script automatically updates the version number in the version.txt file
# if there are updated files during the commit.
# Enable this script using the following command:
# mv -f pre-commit.sh .git/hooks/pre-commit && chmod u+x .git/hooks/pre-commit

version_file=build.info

if [ `git diff --cached --name-only | wc -l` -gt 0 ]
then
  if [ ! -f $version_file ]
  then
    cat > $version_file <<EOF
major=0
minor=0
bugfix=0
EOF
  fi
  source $version_file
  let bugfix++
  cat > $version_file <<EOF
major=$major
minor=$minor
bugfix=$bugfix
EOF
  git add $version_file
fi