Generate a strong secret from the shell

A good tool to generate strong passwords and secrets is "apg". You can get it with

sudo apt-get install apg

To create a strong secret for sessions, hashed Paperclip paths, etc. say

apg -m128 -a1 -E\'\"

Arguments explained:

• The -m parameter defines the secret length
• -a1 makes apg choose from all 7-bit ASCII characters instead of just the alphabet
• -E\'\" excludes quote characters so you can easily paste the secret into a Ruby string

Rails can also generate secrets that can be used for secret_key_base:

$ bin/rails secret
5693040b90b1b09d0a73364d950f15e3a9604403c8e81c6e5bb8b51d0981ef3bbde15a52bf5df41ac4974675bb8e31d69d03490dc11abd1086c873783d1be607