Match concepts from two SKOS code lists

match_code_lists.sh

#!/bin/bash
#
# Match concepts from two SKOS code lists.
# Usage: match_code_lists.sh code_list_1.ttl code_list_2.ttl
# Outputs RDF in Turtle with the links found.

set -e
shopt -s extglob

die () {
  echo >&2 "$@"
  exit 1
}

# Test correct number of arguments.
if [ "$#" -ne 2 ]; then
  die "Two files must be provided for matching!"
fi

# Test if the linked files exist.
for i in "$@"
do
  if [ ! -f $i ]; then
    die "File $i not found!"
  fi
done

! [ $1 == $2 ] || die "Cannot link the same file."

# Test if arq is installed.
command -v arq >/dev/null 2>&1 || die "Missing Jena ARQ!"

QUERY=$(cat <<-END
PREFIX skos: <http://www.w3.org/2004/02/skos/core#>

CONSTRUCT {
  ?a skos:exactMatch ?b .
}
WHERE {
  GRAPH <$1> {
    ?a a skos:Concept ;
      skos:prefLabel ?prefLabel ;
      skos:notation ?notation .
  }
  GRAPH <$2> {
    ?b a skos:Concept ;
      skos:prefLabel ?prefLabel ;
      skos:notation ?notation .
  }
}
END)

arq --namedGraph $1 --namedGraph $2 "${QUERY}"