scrypt is a password-based key derivation function that can be tuned to use a large amount of memory.

I want a command-line interface to calculate the key given my own values for parameters: password, salt, n, r, p, length (these are like the parameters password, salt, cost in bcrypt).

Preferably, I can use something like scrypt --password message --salt mysalt -n 1024 -r 8 -p 8 --length 32 and get just 9a5ef931679f5003248953b6eea3827ca32eb6d07a417126670ba8555f40a0e0.

What software can do this job?