Bash script using Expect - providing input for bash script beforehand.

Bash - Expect

#!/bin/bash

client="client_000"
country=""
state=""
locality=""
org=""
org_unit=""
common_name=""
name=""
email=""
pass=""
company=""
sign="y"
commit="y"

usage=$(cat<<EOF
OPTIONS: \n
	--client      [client_000] \n
	--country     [] \n
	--state       [] \n
	--locality    [] \n
	--org         [] \n
	--org_unit    [] \n
	--common_name [] \n
	--name        [] \n
	--email       [] \n
	--pass        [] \n
	--company     [] \n
	--sign        [y] \n
	--commit      [y] \n
EOF
)

if ! options=$(getopt -o h -l client:,country:,state:,locality:,org:,org_unit:,common_name:,name:,email:,pass:,company:,sign:,commit: -- "$@")
then
    # something wrong
    exit 1
fi


while [ $# -gt 0 ]
do
	case $1 in 
		--client)
			client="$2" ; shift
			;;
		--country)
			country="$2" ; shift
			;;
		--state)
			state="$2" ; shift
			;;
		--locality)
			locality="$2" ; shift
			;;
		--org)
			org="$2" ; shift
			;;
		--org_unit)
			org_unit="$2" ; shift
			;;
		--common_name)
			common_name="$2" ; shift
			;;
		--name)
			name="$2" ; shift
			;;
		--email)
			email="$2" ; shift
			;;
		--pass)
			pass="$2" ; shift
			;;
		--company)
			company="$2" ; shift
			;;
		--sign)
			sign="$2" ; shift
			;;
		--commit)
			commit="$2" ; shift
			;;
		-h)
			echo -e $usage ; exit 0 ;;
    	(--) shift; break;;
    	(-*) echo "$0: error - unrecognized option $1" 1>&2; exit 1;;
    	(*) break;;
	esac
    shift
done

/usr/bin/expect <<EOD
spawn /etc/openvpn/easy-rsa/build-key $client

expect "Country Name"
send "$country\n"

expect "State or Province Name"
send "$state\n"

expect "Locality Name"
send "$locality\n"

expect "Organization Name"
send "$org\n"

expect "Organizational Unit Name"
send "$org_unit\n"

expect "Common Name"
send "$common_name\n"

expect "Name"
send "$name\n"

expect "Email Address"
send "$email\n"

expect "A challenge password"
send "$pass\n"

expect "An optional company name"
send "$company\n"

expect "Sign the certificate?"
send "$sign\n"

expect "certificate requests certified"
send "$commit\n"

interact
sleep 3

EOD

take a look at sexpect. you can write expect scripts with bash only.