Command Section
PWD_MKDB(8)             FreeBSD System Manager's Manual            PWD_MKDB(8)

     pwd_mkdb - generate the password databases

     pwd_mkdb [-BCilLNp] [-d directory] [-s cachesize] [-u username] file

     The pwd_mkdb utility creates db(3) style secure and insecure databases
     for the specified file.  These databases are then installed into
     /etc/spwd.db and /etc/pwd.db respectively.  The file is installed into
     /etc/master.passwd.  The file must be in the correct format (see
     passwd(5)).  It is important to note that the format used in this system
     is different from the historic Version 7 style format.

     The options are as follows:

     -C    Check if the password file is in the correct format.  Do not
           change, add, or remove any files.

     -N    Tell pwd_mkdb to exit with an error if it cannot obtain a lock on
           the file.  By default, we block waiting for a lock on the source
           file.  The lock is held through the rebuilding of the database.

     -p    Create a Version 7 style password file and install it into

     -i    Ignore locking failure of the master.passwd file.  This option is
           intended to be used to build password files in the release process
           over NFS where no contention can happen.  A non-default directory
           must also be specified with the -d option for locking to be
           ignored.  Other use of this option is strongly discouraged.

     -d directory
           Store databases into specified destination directory instead of

     -u username
           Only update the record for the specified user.  Utilities that
           operate on a single user can use this option to avoid the overhead
           of rebuilding the entire database.

     -s cachesize
           Specify in megabytes the size of the memory cache used by the
           hashing library.  On systems with a large user base, a small cache
           size can lead to prohibitively long database file rebuild times.
           As a rough guide, the memory usage of pwd_mkdb in megabytes will be
           a little bit more than twice the figure specified here.  The
           default is 2 megabytes.

     The two databases differ in that the secure version contains the user's
     encrypted password and the insecure version has an asterisk (``*'')

     The databases are used by the C library password routines (see

     By default, the pwd_mkdb utility generates new, machine independent
     format (v4) entries only.  For compatibility with FreeBSD 5.0 and earlier
     releases, the -l option may be specified, which enables generation of
     legacy format (v3) entries.  The legacy format entries are endianness

     The following options may be specified and will affect the generation of
     legacy entries.

     -B    Store data in big-endian format.

     -L    Store data in little-endian format.

     The pwd_mkdb utility exits zero on success, non-zero on failure.

     If the PW_SCAN_BIG_IDS environment variable is set, pwd_mkdb will
     suppress the warning messages that are normally generated for large user
     and group IDs.  Such IDs can cause serious problems with software that
     makes assumptions about the values of IDs.

     /etc/pwd.db                       The insecure password database file.
     /etc/pwd.db.tmp                   A temporary file.
     /etc/spwd.db                      The secure password database file.
     /etc/spwd.db.tmp                  A temporary file.
     /etc/master.passwd                The current password file.
     /etc/passwd                       A Version 7 format password file.

     Regenerate the password database after manually editing or replacing the
     password file:

            /usr/sbin/pwd_mkdb -p /etc/master.passwd

     Previous versions of the system had a program similar to pwd_mkdb,
     mkpasswd(8), which built dbm(3) style databases for the password file but
     depended on the calling programs to install them.  The program was
     renamed in order that previous users of the program not be surprised by
     the changes in functionality.

     chpass(1), passwd(1), db(3), getpwent(3), passwd(5), vipw(8)

     Because of the necessity for atomic update of the password files,
     pwd_mkdb uses rename(2) to install them.  This, however, requires that
     the file specified on the command line live on the same file system as
     the /etc directory.

     There are the obvious races with multiple people running pwd_mkdb on
     different password files at the same time.  The front-ends to pwd_mkdb,
     chpass(1), passwd(1) and vipw(8), handle the locking necessary to avoid
     this problem.

FreeBSD 11.1-RELEASE-p4        February 5, 2014        FreeBSD 11.1-RELEASE-p4
Command Section