How to generate random hex string using OpenSSL

The following command will generate a 32-bytes long random hex string

openssl rand -hex 16

Example:

$ openssl rand -hex 16
122166dd9e2d617246da9af9d7d3cd6f

The command lists 16, not 32 because OpenSSL will generate 16 random binary bytes and then convert these 16 bytes into 32 hex characters.