This will automatically bump the build number of your project's info.plist file when creating an archive for distribution of your app. To use, add this script as a "Run Script" phase to your Xcode build phases, *before* the "Copy Bundle Resources" phase. (It needs to be here so that the updated info.plist file will be copied into the new archive…

Build number auto-bump

#!/bin/bash

##################################################
#
# BuildVersion incrementing script v1.0
#
##################################################

processedPlist="${TARGET_BUILD_DIR}/${INFOPLIST_PATH}"
projectPlist="${INFOPLIST_FILE}"
versionVar="CFBundleVersion"

buildNumber=$(/usr/libexec/PlistBuddy -c "Print ${versionVar}" "${projectPlist}" 2>&1)
if [[ "$buildNumber" == *Does\ Not\ Exist ]] ; then
buildNumber=1
echo "Create ${versionVar} and set to ${buildNumber}"
/usr/libexec/PlistBuddy -c "Add :${versionVar} String ${buildNumber}" "${processedPlist}"
/usr/libexec/PlistBuddy -c "Add :${versionVar} String ${buildNumber}" "${projectPlist}"
else
buildNumber=$(($buildNumber + 1))
echo "set ${versionVar} to ${buildNumber}"
/usr/libexec/PlistBuddy -c "Set :${versionVar} ${buildNumber}" "${processedPlist}"
/usr/libexec/PlistBuddy -c "Set :${versionVar} ${buildNumber}" "${projectPlist}"
fi