openssl-rand
Generate random bytes using a cryptographically secure PRNG. tldr-pages
On several platforms
Several platforms
Generate an 8-byte (16 characters) hex string and write it to stdout
openssl rand -hex 8IdentifyGenerate 20 random bytes encoded in base64
openssl rand -base64 20IdentifyGenerate random bytes and write them to a file (without encoding)
openssl rand -out path/to/file lengthIdentifyGenerate 1 KiB/MiB/GiB/TiB random bytes encoded in hex/base64
openssl rand -hex 1KIdentify