unwrap an eCryptfs mount passphrase from file.
printf "%s" "wrapping passphrase" | ecryptfs-unwrap-passphrase [file] -
ecryptfs-unwrap-passphrase is a utility to unwrap an eCryptfs mount passphrase from file, using a specified wrapping passphrase, and display the decrypted result on standard out.
This manpage was written by Dustin Kirkland <email@example.com> for Ubuntu systems (but may be used by others). Permission is granted to copy, distribute and/or modify this document under the terms of the GNU General Public License, Version 2 or any later version published by the Free Software Foundation.
On Debian and Ubuntu systems, the complete text of the GNU General Public License can be found in /usr/share/common-licenses/GPL.