If is unable to create a mailbox lock file, it will call
       this program.  This makes using the mailbox safe over i.e. NFS. There
       is no reason to call mlock yourself or through another program.  It is
       setgid mail so there is no need to change the permissions of /var/mail
       to 1777.

       No documentation other than this crappy man page,

       mlock was written by Mark Crispin <> This man
       page was written for Debian GNU/Linux by Jaldhar H. Vyas

UW IMAP 2007f~dfsg-4              2014-10-24                          MLOCK(1)
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