Determine the modulus of a certificate, key or certificate request and output it for the purposes of comparing them to confirm they match

getmodulus.sh

#!/bin/bash

if grep -- ' PRIVATE KEY-' "$1" >/dev/null; then
  modulus="`openssl rsa -noout -modulus -in "$1" | md5sum | awk '{print $1}'`"
elif grep -- '-BEGIN CERTIFICATE REQUEST-' "$1" >/dev/null; then
  modulus="`openssl req -noout -modulus -in "$1" | md5sum | awk '{print $1}'`"
elif grep -- '-BEGIN CERTIFICATE-' "$1" >/dev/null; then
  modulus="`openssl x509 -noout -modulus -in "$1" | md5sum | awk '{print $1}'`"
else
  modulus="unknown"
fi

#if [ "${1##*.}" = "key" ]; then
#  modulus="`openssl rsa -noout -modulus -in $1 | md5sum | awk '{print $1}'`"
#elif [ "${1##*.}" = "crt" ]; then
#  modulus="`openssl x509 -noout -modulus -in $1 | md5sum | awk '{print $1}'`"
#elif [ "${1##*.}" = "csr" ]; then
#  modulus="`openssl req -noout -modulus -in $1 | md5sum | awk '{print $1}'`"
#else
#  modulus="unknown"
#fi

echo "$modulus $1"