| Debugging with GDB: Command History |
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GDB can keep track of the commands you type during your debugging sessions, so that you can be certain of precisely what happened. Use these commands to manage the GDB command history facility.
GDB uses the GNU History library, a part of the Readline package, to provide the history facility. See Using History Interactively, for the detailed description of the History library.
To issue a command to GDB without affecting certain aspects of the state which is seen by users, prefix it with ‘server ’ (see Server Prefix). This means that this command will not affect the command history, nor will it affect GDB’s notion of which command to repeat if RET is pressed on a line by itself.
The server prefix does not affect the recording of values into the value
history; to print a value without recording it into the value history,
use the output command instead of the print command.
Here is the description of GDB commands related to command history.
set history filename fname
Set the name of the GDB command history file to fname.
This is the file where GDB reads an initial command history
list, and where it writes the command history from this session when it
exits. You can access this list through history expansion or through
the history command editing characters listed below. This file defaults
to the value of the environment variable GDBHISTFILE, or to
./.gdb_history (./_gdb_history on MS-DOS) if this variable
is not set.
set history save
set history save on
Record command history in a file, whose name may be specified with the
set history filename command. By default, this option is disabled.
set history save off
Stop recording command history in a file.
set history size size
set history size unlimited
Set the number of commands which GDB keeps in its history list.
This defaults to the value of the environment variable GDBHISTSIZE, or
to 256 if this variable is not set. Non-numeric values of GDBHISTSIZE
are ignored. If size is unlimited or if GDBHISTSIZE is
either a negative number or the empty string, then the number of commands
GDB keeps in the history list is unlimited.
set history remove-duplicates count
set history remove-duplicates unlimited
Control the removal of duplicate history entries in the command history list.
If count is non-zero, GDB will look back at the last count
history entries and remove the first entry that is a duplicate of the current
entry being added to the command history list. If count is
unlimited then this lookbehind is unbounded. If count is 0, then
removal of duplicate history entries is disabled.
Only history entries added during the current session are considered for removal. This option is set to 0 by default.
History expansion assigns special meaning to the character !. See Event Designators, for more details.
Since ! is also the logical not operator in C, history expansion
is off by default. If you decide to enable history expansion with the
set history expansion on command, you may sometimes need to
follow ! (when it is used as logical not, in an expression) with
a space or a tab to prevent it from being expanded. The readline
history facilities do not attempt substitution on the strings
!= and !(, even when history expansion is enabled.
The commands to control history expansion are:
set history expansion on
set history expansion
Enable history expansion. History expansion is off by default.
set history expansion off
Disable history expansion.
show history
show history filename
show history save
show history size
show history expansion
These commands display the state of the GDB history parameters.
show history by itself displays all four states.
show commands
Display the last ten commands in the command history.
show commands n
Print ten commands centered on command number n.
show commands +
Print ten commands just after the commands last printed.
Next: Screen Size, Previous: Editing, Up: Controlling GDB [Contents][Index]