Tool to show cert, key or CSR information for a file or site

show

#!/bin/bash

if [ -e "$1" ]; then
  if grep -- ' PRIVATE KEY-' "$1" >/dev/null; then
    action=rsa
  elif grep -- '-BEGIN CERTIFICATE REQUEST-' "$1" >/dev/null; then
    action=req
  elif grep -- '-BEGIN CERTIFICATE-' "$1" >/dev/null; then
    action=x509
  else
    action=unknown
  fi
  if [ "$action" = "unknown" ]; then
    echo "Couldn't detect the file type of $1"
    exit 1
  fi
  echo -n | openssl $action -in "$1" -noout -text
else
  echo -n | openssl s_client -connect $1:443 | openssl x509 -text
fi

See also https://github.com/mozilla-it/cert-tools/blob/master/ssl-inspect