mkdir -p "${SAGE_DOC}"
cd "${SAGE_INST_LOCAL}/share/doc/sage"
for a in *; do
    if [ -e "$a" -a ! -e "${SAGE_DOC}/$a" ]; then
        ln -sf "${SAGE_INST_LOCAL}/share/doc/sage/$a" "${SAGE_DOC}/$a"
    fi
done
