A number of gdbmtool parameters is kept in its internal
variables. To examine or modify variables, use the set command
(see set).
Whether to ask for confirmation before certain destructive operations, such as truncating the existing database.
Default is true.
A string used to delimit fields of a structured datum on output (see definitions).
Default is ‘,’ (a comma). This variable cannot be unset.
A string used to delimit array items when printing a structured datum (see definitions).
Default is ‘,’ (a comma). This variable cannot be unset.
Comma-delimited list of GDBM error codes which cause program
termination. Error codes are specified via their canonical names
(see Error codes). The GDBM_ prefix can be omitted. Code
name comparison is case-insensitive. Each error code can optionally
be prefixed with minus sign, to indicate that it should be removed
from the resulting list, or with plus sign (which is allowed for
symmetry). A special code ‘all’ stands for all available error codes.
In boolean context, the true value is equivalent to ‘all’,
and false (i.e. variable unset) is equivalent to ‘-all’.
This variable cannot be set from interactive sessions.
Comma-delimited list of GDBM error codes which are masked, i.e.
which won’t trigger a diagnostic message if they occur. The syntax is
the same as described for errorexit.
The name and command line of the pager program to pipe output to. This program is used in interactive mode when the estimated number of output lines is greater then the number of lines on your screen.
The default value is inherited from the environment variable
PAGER. Unsetting this variable disables paging.
Primary prompt string. Its value can contain conversion specifiers, consisting of the ‘%’ character followed by another character. These specifiers are expanded in the resulting prompt as follows:
| Sequence | Expansion |
|---|---|
| %f | name of the current database file |
| %p | program invocation name |
| %P | package name (‘GDBM’) |
| %v | program version |
| %_ | single space character |
| %% | % |
The default value is ‘%p>%_’, i.e. the program name, followed by a “greater than” sign, followed by a single space.
Secondary prompt. See ps1 for a description of its value.
This prompt is displayed before reading the second and subsequent
lines of a multi-line command.
The default value is ‘%_>%_’.
When each command terminates, print an additional line listing times spent in that command. The line is formatted as follows:
[reorganize r=0.070481 u=0.000200 s=0.000033]
Here, ‘reorganize’ is the name of the command that finished, the number after ‘r=’ is real time spent executing the command, the number after ‘u=’ is the user CPU time used and the number after ‘s=’ is the system CPU time used.
Enable command tracing. This is similar to the shell -t
option: before executing each command, gdbmtool will print
on standard error a line starting with a plus sign and followed by the
command name and its arguments.
Whether to display a welcome banner at startup. To affect
gdbmtool, this variable should be set in a startup script
file (see startup files). See -q option.
The following variables control how the database is opened:
Sets the block size. See block_size. Unset by default.
Sets the cache size. See GDBM_SETCACHESIZE.
This variable affects the currently opened database immediately. It
is also used by open command.
To enable automatic cache size selection, unset this variable. This is the default.
Name of the database file. If the open command is called
without argument (e.g. called implicitly), this variable names the
database file to open. If open is called with file name
argument, upon successful opening of the database the filename
variable is initialized with its file name.
This variable cannot be unset.
File descriptor of the database file to open. If this variable is
set, its value must be an open file descriptor referring to a
GDBM database file. The open command will use
gdbm_fd_open function to use this file (see gdbm_fd_open).
When this database is closed, the descriptor will be closed as well
and the fd variable will be unset.
See also the -d (--db-descriptor) command line option in invocation.
Defines the format in which new databases will be created. Allowed values are:
Databases will be created in standard format. This is the format used
by all GDBM versions prior to 1.21. This value is the
default.
Extended format, best for crash-tolerant applications. See Numsync, for a discussion of this format.
Open mode. The following values are allowed:
Truncate the database if it exists or create a new one. Open it in read-write mode.
Technically, this sets the GDBM_NEWDB flag in call to gdbm_open.
See GDBM_NEWDB.
Open the database in read-write mode. Create it if it does not exist. This is the default.
Technically speaking, it sets the GDBM_WRCREAT flag in call to
gdbm_open. See GDBM_WRCREAT.
Open the database in read-only mode. Signal an error if it does not exist.
This sets the GDBM_READER flag (see GDBM_READER).
Attempting to set any other value or to unset this variable results in error.
File mode (in octal) for creating new database files and database dumps.
Lock the database. This is the default.
Setting this variable to false or unsetting it results in passing
GDBM_NOLOCK flag to gdbm_open (see GDBM_NOLOCK).
Use memory mapping. This is the default.
Setting this variable to false or unsetting it results in passing
GDBM_NOMMAP flag to gdbm_open (see GDBM_NOMMAP).
Flush all database writes on disk immediately. Default is false. See GDBM_SYNC.
Enables the coalesce mode, i.e. merging of the freed blocks of
GDBM files with entries in available block lists. This
provides for effective memory management at the cost of slight
increase in execution time when calling
gdbm_delete. See GDBM_SETCOALESCEBLKS.
This variable affects the currently opened database immediately and
will be used by open command, when it is invoked.
Set to true, enables the use of central free block pool in
newly opened databases. See GDBM_SETCENTFREE.
This variable affects the currently opened database immediately and
will be used by open command, when it is invoked.
The following commands are used to list or modify the variables:
When used without arguments, lists all variables and their values.
Unset variables are shown after a comment sign (‘#’). For string
and numeric variables, values are shown after an equals sign. For
boolean variables, only the variable name is displayed if the variable
is true. If it is false, its name is prefixed with
‘no’.
For example:
# blocksize is unset # cachesize is unset nocentfree nocoalesce confirm delim1="," delim2="," # fd is unset filemode=644 filename="junk.gdbm" format="standard" lock mmap open="wrcreat" pager="less" ps1="%p>%_" ps2="%_>%_" # quiet is unset nosync
If used with arguments, the set command alters the specified
variables. In this case, arguments are variable assignments in the
form ‘name=value’. For boolean variables, the
value is interpreted as follows: if it is numeric, 0
stands for false, any non-zero value stands for true.
Otherwise, the values on, true, and yes denote
true, and off, false, no stand for
false. Alternatively, only the name of a boolean variable can be
supplied to set it to true, and its name prefixed with
no can be used to set it to false. For example, the following
command sets the delim2 variable to ‘;’ and the
confirm variable to false:
set delim2=";" noconfirm
Unsets the listed variables. The effect of unsetting depends on the
variable. Unless explicitly described in the discussion of the
variables above, unsetting a boolean variable is equivalent to setting it to
false. Unsetting a string variable is equivalent to assigning it
an empty string.