Auto-incrementing build numbers in Xcode 4.3 (based on http://davedelong.com/node/37)

gistfile1.txt

#!/bin/bash

# Set the marketing version of the project.
# Take the number from git and apply it to the project.
# Any "v" prepended to the git tag will be removed.

# Get the current release description from git.
git_version=`git describe --tags`

# Check to see if the tag starts with with "v", and remove if so.
if [[ "${git_version}" == v* ]]; then
    git_version="${git_version#*v}"
fi

git_head=`git rev-parse --short HEAD`

# Create the full version
version="${git_version} ${git_head}"

# Set the version number
/usr/libexec/PlistBuddy -c "Set :CFBundleShortVersionString $version" "$BUILT_PRODUCTS_DIR/$INFOPLIST_PATH"

# Set the build number, CFBundleVersion (misnomer a la Apple)
if [ -f "$PROJECT_DIR/BUILD" ]
then
    build_number=`cat "$PROJECT_DIR/BUILD"`
    build_number=$(($build_number + 1))
    
else
    build_number=1
fi
# Store the version number in a file at the project root: BUILD
echo "$build_number" > "$PROJECT_DIR/BUILD"

# Set the build number
/usr/libexec/PlistBuddy -c "Set :CFBundleVersion $build_number" "$BUILT_PRODUCTS_DIR/$INFOPLIST_PATH"

Include quotation marks around plist values, Xcode does funky things with spaces in project names.

See http://paulpeelen.com/2011/08/03/automatic-incremental-build-number-in-xcode-4-3/ for how to insert into XCode build phases.