Create a password with openssl passwd without asking for a prompt

openssl-no-prompt-passwd.md

You can generate a password without a prompt by piping text into openssl and passing a new flag. For example:

echo "password" | openssl passwd -apr1 -stdin

This will echo to stdout. This way you can write a script or something instead of having to use the prompt to type in the password.

If you still wanted to append the output to the /etc/nginx/.htpasswd file, then you would do the following:

echo "password" | openssl passwd -apr1 -stdin >> /etc/nginx/.htpasswd

Note passing password value using double-quotes can get ugly in case the password value contains $.