This package includes several programs to safely lock and unlock
files and mailboxes from the command line.  These include:

   lockfile-create
   lockfile-remove
   lockfile-touchlock
   mail-lock
   mail-unlock
   mail-touchlock

These programs use liblockfile to perform the file locking and
unlocking, so they are guaranteed compatible with Debian's
file locking policies.

WWW: https://tracker.debian.org/pkg/lockfile-progs