source: install/scripts/upgrade_check.sh @ 411

#!/bin/sh -e

# this script will look for upgrade scripts in
# /usr/share/alternc/install/upgrades and execute them based on the
# extension
#
# usage:
# $0 oldvers, where oldvers is the version of the package previously
# installed
#
# an upgrade file is considered only if its basename is a version
# number greater than the $oldvers argument

# remove version from filename by stripping the extension
strip_ext() {
        echo $1 | sed 's/\.[^.]*$//'
}

# find the version from a filename by stripping everything but the extension
get_ext() {
        echo $1 | sed 's/^.*\.\([^.]*\)$/\1/'
}

oldvers=$1

if [ -z "$oldvers" ] || [ "$oldvers" == '<unknown>' ]; then
        # this is not an upgrade
        exit 0
fi

# the upgrade script we are considering
extensions="*.sh *.php *.sql"
cd /usr/share/alternc/install/upgrades
for file in $extensions
do
        if [ -r $file ]; then
                # the version in the filename
                upvers=`strip_ext $file`
                # the extension
                ext=`get_ext $file`
                if dpkg --compare-versions $upvers gt $oldvers; then
                  echo running upgrade script $file
                  # run the proper program to interpret the upgrade script
                  case "$ext" in
                  sql)
                        mysql -h $MYSQL_HOST -u $MYSQL_USER -p$MYSQL_PASS $MYSQL_DATABASE \
                        < $file
                        ;;
                  php)
                        php4 -q $file
                        ;;
                  sh)
                        sh $file
                        ;;
                  esac
                else
                  echo "not running script $file, too old u$upvers o$oldvers"
                fi
        fi
done