shell script to compare cacert files

compare-cacert.sh

#!/usr/bin/env bash
set -eu
parse_bundle() {
        # https://serverfault.com/questions/590870/how-to-view-all-ssl-certificates-in-a-bundle
        openssl crl2pkcs7 -nocrl -certfile $1 | openssl pkcs7 -print_certs
}
echo "Comparing certs in $1 and $2" >&2
tmpdir=$(mktemp -d)
parse_bundle $1 > $tmpdir/a
parse_bundle $2 > $tmpdir/b
pushd $tmpdir
echo "Comparing output in $tmpdir" >&2
diff  -u a b
popd
trap "rm -vr $tmpdir" EXIT