If you have a list of keys and SSL certs and don’t know which cert belongs with which key, here’s a script for you. It’s not efficient (nested for loop!), but it gets the job done quickly.1

#!/bin/bash
for i in `ls *.key` 
do
key_mod=`openssl rsa -noout -in $i -modulus`
for j in `ls *.cer`
do
x509_mod=`openssl x509 -noout -in $j -modulus`
if [ "$x509_mod" == "$key_mod" ]; then
echo "$j matches $i"
fi 
done
done
  1. If bash allowed multidimensional or associative arrays this would be trivial to optimize. ↩