Parse audio track times from an audacity .aup project

parse-aup.sh

#!/bin/sh

# Parse audio track times from an audacity .aup project
# Copyright (C) 2012  William Heinbockel <heinbockel@redhat.com>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

if [ $# -ne 1 ]
then echo "Usage: $0 audacity.aup"
    exit 1
fi

if [ ! -r "$1" ]
then echo "Error: cannot find audacity file: $1"
    exit 1
fi

# Get track lengths
cat <<- EOF | xsltproc --novalid --nonet - "$1"
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0"
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:a="http://audacity.sourceforge.net/xml/">
    <xsl:output method="text"/>
    <xsl:variable name="rate" select="/a:project/@rate"/>
    <xsl:template match="/a:project">
        <xsl:for-each select="a:wavetrack">
            <xsl:value-of select="concat('Slide ',position(),': ',round(sum(a:waveclip/a:sequence/@numsamples) div \$rate),'s')"/>
            <xsl:text>
</xsl:text>
        </xsl:for-each>
        <xsl:value-of select="concat('Total: ',round(sum(a:wavetrack/a:waveclip/a:sequence/@numsamples) div \$rate) div 60,'min')"/>
        <xsl:text>
</xsl:text>
    </xsl:template>
    <xsl:template match="text()"/>
</xsl:stylesheet>
EOF

Many thanks, but how to use it?