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db_dump185

NAME

db_dump185 - dump DB 1.85 legacy database files

SYNOPSIS

db_dump185 [-p] [-f output] db_file

DESCRIPTION

The db_dump185 utility reads the version 1.85 database file db_file and writes it to the standard output using a portable flat-text format understood by the db_load(1) utility. The argument db_file must be a file produced using the version 1.85 DB library functions.

The options are as follows:

-f

Write to the specified file instead of to the standard output.

-p

If characters in either the key or data items are printing characters (as defined by isprint(3)), use printing characters in file to represent them. This option permits users to use standard text editors to modify the contents of databases.

Note, different systems may have different notions as to what characters are ``printing'', and databases dumped in this manner may be less portable to external systems.

Dumping and reloading hash databases that use user-defined hash functions will result in new databases that use the default hash function. While using the default hash function may not be optimal for the new database, it will continue to work correctly.

Dumping and reloading btree databases that use user-defined prefix or comparison functions will result in new databases that use the default prefix and comparison functions. In this case, it is quite likely that the database will be damaged beyond repair permitting neither record storage or retrieval.

The only available workaround for either case is to modify the sources for the db_load(1) utility to load the database using the correct hash, prefix and comparison functions.

The db_dump utility exits 0 on success, and >0 if an error occurs.

OUTPUT FORMATS

There are two output formats used by db_dump.

In both output formats, the first few lines of the output contain header information describing the underlying access method, filesystem page size and other bookkeeping information. This information is output in ``name=value'' pairs, where ``name'' may be any of the keywords listed in the db_load(1) manual page, and ``value'' will be its value. While this header information can be edited before the database is reloaded, there is rarely any reason to do so, as all of this information can be overridden by command-line arguments to db_load.

Following the header information are the key/data pairs from the database. If the database being dumped is of type btree or hash, the output will be paired lines of text, where the first line of the pair is the key item, and the second line of the pair is its corresponding data item. If the database being dumped is of type recno, the output will be lines of text, where each line is a new data item for the database.

If the -p option was specified, each output line will consist of single characters representing any characters from the database that were ``printing'', and backslash (``\'') escaped characters for any that were not. Backslash characters appearing in the output mean one of two things: if the backslash character precedes another backslash character, it means that a literal backslash character occurred in the key or data item. If the backslash character precedes any other character, the next two characters should be interpreted as hexadecimal specification of a single character, e.g., ``\0a'' is a newline character in the ASCII character set.

If the -p option was not specified, each output line will consist of paired hexadecimal values, e.g., the line ``726f6f74'' is the string ``root'' in the ASCII character set.

In both output formats, a single newline character ends both the key and data items.

SEE ALSO

isprint(3)

The DB library is a family of classes that provides a modular programming interface to transactions and record-oriented file access. The library includes support for transactions, locking, logging and file page caching, as well as various indexed access methods. Many of the classes (e.g., the file page caching class) are useful independent of the other DB classes, although some classes are explicitly based on other classes (e.g., transactions and logging).

db_archive(1), db_checkpoint(1), db_deadlock(1), db_dump(1), db_load(1), db_recover(1), db_stat(1). (Note that on Debian systems, some of these manpages and programs have been renamed to things like db4.3_stat to distinguish between the multiple DB versions.)