Freebsd- Pdfcrack A Command Line Password: Linux //free\\

You can download the latest version (e.g., 0.16) from SourceForge and compile it manually. Essential Command-Line Usage

Provide a known user password to speed up owner password cracking. --loadstate Continue recovery from a previously saved state. Perform a benchmark of your system's cracking speed. Key Features and Limitations Linux FreeBSD- PDFCrack A Command Line Password

Success output:

sudo dnf install pdfcrack