Simplest credential manager you can think of :)

daemon.sh

#!/bin/sh

set -e

# path of fifo, must be unique for this instance.
# so if you want several daemons running you need to fix this.
FIFO_PATH=/tmp/credmanager.sock

# read passphrase from user and store in var
echo -n "Enter passphrase: "
read -r passphrase
echo "Passphrase stored. Daemon ready."

# repeat passphrase infinity times to named pipe
while true; do
	# create fifo
	rm -f "${FIFO_PATH}"
	mkfifo -m 600 "${FIFO_PATH}"
	# actually write passphrase to pipe
	echo "${passphrase}" > "${FIFO_PATH}"
done