EDIT

#!/bin/bash

MYSQL_HOST=127.0.0.1

MYSQL_PORT=13306

MYSQL_USR='xxx'

MYSQL_PWD='xxx'

MYSQL_DB='redmine'

MYSQL="mysql -h $MYSQL_HOST -P$MYSQL_PORT -u$MYSQL_USR -p$MYSQL_PWD $MYSQL_DB"

#----------------------

# table custom_values fiels:

# id    customized_type   customized_id   custom_field_id value

echo 'SELECT * FROM custom_values c  WHERE c.custom_field_id=8  AND value IS NOT NULL' | $MYSQL > kdata

rm -f tags.sql taggings.sql

awk -f split-kdata.awk kdata

echo "Clearing tables"

echo "DELETE FROM tags; DELETE FROM taggings;" | $MYSQL

echo "Creating tags"

cat tags.sql | $MYSQL

echo "Creating taggings"

cat taggings.sql | $MYSQL