PWD_MKDB(8) BSD System Manager’s Manual PWD_MKDB(8)


pwd_mkdb — generate the password databases


pwd_mkdb [−c] [−p −s] [−d directory] [−u username] file


pwd_mkdb 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:


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


Create a Version 7 style password file and install it into /etc/passwd.


Only update the secure version of the database. This is most commonly used in conjunction with the −u flag during a password change. Because the insecure database doesn’t contain the password there is no reason to update it if the only change is in the password field. Cannot be used in conjunction with the −p flag.

−d directory

Operate in a base directory other than the default of /etc. All absolute paths (including file) will be made relative to directory. Any directories specified as a part of file will be stripped off. This option is used to create password databases in directories other than etc; for instance in a chroot(8) jail.

−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. This option must never be used if the line number of the user’s record in /etc/master.passwd has changed.


The absolute path to a file in master.passwd format, as described in passwd(5).

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 getpwent(3)).

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


current password file


a Version 7 format password file


insecure password database file


temporary file


secure password database file


temporary file


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


Previous versions of the system had a program similar to pwd_mkdb, mkpasswd, 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.


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.

BSD June 6, 1993 BSD