add ssh-keys whith the same passphrase

add-keys.bash

#!/bin/bash

declare -r keys_dir='/home/user/.ssh/'
declare -r keys='
    key0.ppk
    key1.ppk
    key2.ppk
    keyN.ppk
'

echo -n 'Passphrase: '
read -s pass
echo

for key in $keys
do
    expect > /dev/null 2>&1 << EOF
        spawn ssh-add ${keys_dir}${key}
        expect "Enter passphrase"
        send "${pass}\r"
        expect eof
EOF
done

ssh-add -l

exit 0