Comprehensive and Detailed in Depth

Vault provides multiple valid ways to create a policy via the CLI using the vault policy write command. The HashiCorp Vault documentation states: 'To write a policy, use the vault policy write command.' The valid methods are:

A: 'vault policy write my-policy - << EOF ... EOF uses heredoc syntax to inline policy content, which Vault accepts directly.'

C: 'vault policy write my-policy /tmp/policy.hcl writes a policy from a file, a standard method per the docs: 'The policy can be read from a file or piped from stdin.''

D: 'cat user.hcl | vault policy write my-policy - pipes policy content from a file via stdin, another documented approach: 'You can pipe the policy content to the command using -.''

Option B, vault policy create, is invalid as no such command exists---only vault policy write is used. Thus, A, C, and D are correct.

HashiCorp Vault Documentation - Policies: Write a Policy