db_dump
db_dump [-d] [-f output] db_file
db_dump [-p] [-f output] [-h home] db_file
db_dump185 [-p] [-f output] db_file
DESCRIPTION
The db_dump utility reads the 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 DB
library functions.
The db_dump185 utility is similar to the db_dump utility
except that it reads databases in the format used by DB
versions 1.85 and 1.86.
The options are as follows:
-d Dump the specified database in a format helpful for
debugging the DB library routines. The output format
of the -d option is not standard and may change,
without notice, between releases of the DB library.
-f Write to the specified file instead of to the
standard output.
-h Specify a home directory for the database. As DB
versions before 2.0 did not support the concept of a
database ``home'', db_dump185 does not support this
option.
-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_dump185 utility may not be available on your system
as it is not always installed when the DB libraries and
utilities are installed. If you are unable to find it,
see your system administrator for further information.
The db_dump utility exits 0 on success, and >0 if an error
occurs. The db_dump185 utility exits 0 on success, and >0
if an error occurs.
OUTPUT FORMATS
There are two output formats used by db_dump and
db_dump185.
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.
ENVIRONMENT VARIABLES
The following environment variables affect the execution
of db_dump:
DB_HOME
If the -h option is not specified and the environment
variable DB_HOME is set, it is used as the path of
the database home, as described in db_appinit(3).
SEE ALSO
isprint(3)
The DB library is a family of groups of functions 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 functional groups (e.g., the file page caching
functions) are useful independent of the other DB
functions, although some functional groups are explicitly
based on other functional groups (e.g., transactions and
logging). For a general description of the DB package,
see db_intro(3).
db_archive(1), db_checkpoint(1), db_deadlock(1), db_dump(1),
db_load(1), db_recover(1), db_stat(1), db_intro(3),
db_appinit(3), db_cursor(3), db_dbm(3), db_internal(3),
db_lock(3), db_log(3), db_mpool(3), db_open(3), db_thread(3),
db_txn(3)
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