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man pages section 8: System Administration Commands

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Updated: Wednesday, July 27, 2022



makedbm - make a dbm file, or get a text file from a dbm file


makedbm [-b] [-l] [-s] [-E] [-i yp_input_file]
     [-o yp_output_name] [-d yp_domain_name]
     [-m yp_master_name] [-S delimiter]
     [-D number_of_delimiters] infile outfile
makedbm [-u dbmfilename]


The makedbm utility takes the infile and converts it to a pair of files in ndbm format (see ndbm(3C)), namely outfile.pag and outfile.dir. Each line of the input file is converted to a single dbm record. All characters up to the first TAB or SPACE form the key, and the rest of the line is the data. If a line ends with ‘\’ (backslash), the data for that record is continued on to the next line. makedbm does not treat ‘#’ (pound-sign) as a special character.

Because makedbm is mainly used in generating dbm files for the NIS name service, it generates a special entry with the key yp_last_modified, which is the date of infile (or the current time, if infile is ‘−’). The entries that have keys with the prefix yp_ are interpreted by NIS server utilities.


The following options are supported:


Insert the YP_INTERDOMAIN into the output. This key causes ypserv(8) to use DNS for host name and address lookups for hosts not found in the maps.

–d yp_domain_name

Create a special entry with the key yp_domain_name.

–D number_of delimiters

Specify number_of_delimiters to skip before forming the key.


Delimiters are escaped.

–i yp_input_file

Create a special entry with the key yp_input_file.


Lowercase. Convert the keys of the given map to lowercase, so that, for example, host name matches succeed independent of case distinctions.

–m yp_master_name

Create a special entry with the key yp_master_name. If no master host name is specified, yp_master_name is set to the local host name.

–o yp_output_name

Create a special entry with the key yp_output_name.


Secure map. Accept connections from secure NIS networks only.

–S delimiter

Specify the delimiter to use instead of the default delimiter for forming the key.

–u dbmfilename

Undo a dbm file. Prints out the file in text format, one entry per line, with a single space separating keys from values.


The following operands are supported:


Input file for makedbm. If infile is ‘’ (dash), the standard input is read.


One of two output files in ndbm format: outfile.pag and outfile.dir.


See attributes(7) for descriptions of the following attributes:


See Also

ndbm(3C), attributes(7), ypserv(8)