openssl encrypt/decrypt script, requires public key in pem format

encrypt.sh

#!/bin/bash

if [ $1 == "-d" ]; then
    if [ ! -r $2 ]; then
	echo 'supply a valid input file to decrypt'
	exit 1
    fi
    openssl rsautl -decrypt -inkey $HOME/.ssh/id_rsa -in $2 2> /dev/null
    exit 0
fi

if [ ! -r $1 ]; then
    echo 'supply a valid input file to encrypt'
    exit 1
fi

openssl rsautl -encrypt -pubin -inkey $HOME/.ssh/id_rsa.pub.pem -in $1