pdf

gs -dBATCH -dNOPAUSE -sDEVICE=pdfwrite -sOUTPUTFILE=test.pdf (echo -e "@color{0.5 0 0} @font{Courier-Bold36} \n\n\n foo" | enscript --no-header -e@ -p - | psub)

qpdf --decrypt protected.pdf --password=<your-password> out.pdf

qpdf --decrypt protected.pdf --password-file=- out.pdf

Notes on passing the password

Allow Password Input From Standard Input for Increased Security #1188 - github.com

Reads the first line from the specified file and uses it as the password for accessing encrypted files. filename may be - to read the password from standard input, but if you do that the password is echoed and there is no prompt, so use - with caution. Note that leading and trailing spaces are not stripped from the password. – https://qpdf.readthedocs.io/en/stable/cli.html#general-options

Press enter, then CTRL+D after entering the password.