17.6. Group Listing of GDB Commands

This section summarizes the GDB commands by task. Esoteric commands, such as those used by GDB's maintainers, or to cross-debug remote systems connected via serial port or a network, have been omitted.

17.6.1. Aliases for Other Commands

Alias	Short for...	Alias	Short for...	Alias	Short for...
bt	backtrace	f	frame	p	print
c	continue	fo	forward-search	po	print-object
cont	continue	gcore	generate-core-file	r	run
d	delete	h	help	s	step
dir	directory	i	info	share	sharedlibrary
dis	disable	l	list	si	stepi
do	down	n	next	u	until
e	edit	ni	nexti	where	backtrace

17.6.2. Breakpoints

awatch	Set an expression watchpoint.
break	Set a breakpoint at a line or function.
catch	Set a catchpoint to catch an event.
clear	Clear a given breakpoint.
commands	Specify commands to run when a breakpoint is reached.
condition	Supply a condition to a particular breakpoint.
delete	Delete one more breakpoints or auto-display expressions.
disable	Disable one or more breakpoints.
enable	Enable one or more breakpoints.
hbreak	Set a hardware assisted breakpoint.
ignore	Set the ignore-count of a particular breakpoint.
rbreak	Set a breakpoint for all functions matching a regular expression.
rwatch	Set a read watchpoint for an expression.
tbreak	Set a temporary breakpoint.
tcatch	Set a temporary catchpoint.
thbreak	Set a temporary hardware assisted breakpoint.
watch	Set an expression watchpoint.

17.6.3. Examining Data

call	Call a function in the program.
delete display	Cancel one or more expressions that have been set to display when the program stops.
delete mem	Delete a memory region.
disable display	Disable one or more expressions that have been set to display when the program stops.
disable mem	Disable a memory region.
disassemble	Disassemble a section of memory.
display	Print the value of an expression each time the program stops.
enable display	Enable one or more expressions that have been set to display when the program stops.
enable mem	Enable a memory region.
inspect	Same as print.
mem	Define attributes for a memory region.
output	Similar to print, but doesn't save the value in history and doesn't print a newline. For scripting.
print	Print the value of an expression.
print-object	Cause an Objective C object to print information about itself.
printf	Print values like the printf command.
ptype	Print the definition of a given type.
set	Evaluate an expression and save the result in a program variable.
set variable	Same as set, avoids conflict with GDB variables.
undisplay	Cancel one or more expressions that have been set to display when the program stops.
whatis	Print the data type of an expression.
x	Examine memory: x/fmt address. See the entry for x in the later section "Alphabetical Summary of GDB Commands."

17.6.4. Controlling and Examining Files

add-symbol-file

Add symbols from a dynamically loaded file to GDB's symbol table.

add-symbol-file-from-memory

Load the symbols from a dynamically loaded object file in the debuggee's memory.

cd

Set the current directory for GDB and the debuggee.

core-file

Specify a file to use as the core dump for memory and register contents.

directory

Add a directory to the beginning of the source file search path.

edit

Edit a file or function.

exec-file

Specify a file to use as the executable.

file

Specify the filename of the program to be debugged.

forward-search

Search forward in the current source file for a regular expression, starting at the last line listed.

generate-core-file

Create a core file from the current state of the debuggee.

list

List a function or line.

nosharedlibrary

Unload all shared object library symbols.

path

Add one or more directories to the object file search path.

pwd

Print the current directory.

reverse-search

Search backward in the current source file for a regular expression, starting at the last line listed.

search

Same as forward-search.

section

Change the base address of a particular section in the exec file.

sharedlibrary

Load shared object library symbols for files matching a regular expression.

symbol-file

Load symbol table information from a specified executable file.

17.6.5. Running a Program

advance	Continue the program up to the given location.
attach	Attach to a process or file outside of GDB.
continue	Continue the program being debugged.
detach	Detach a previously attached process or file.
finish	Execute until selected stack frame returns.
handle	Specify how to handle a signal.
interrupt	Interrupt the execution of the debugged program.
jump	Continue program being debugged at specified line or address.
kill	Kill the program being debugged.
next	Execute the program's next statement.
nexti	Execute the program's next instruction.
run	Start the debugged program.
signal	Continue the program, giving it a specified signal.
start	Run the debugged program until the beginning of the main procedure. Useful for C++ where constructors run before main( ).
step	Step the program until it reaches a different source line. Descends into called functions.
stepi	Step exactly one instruction.
thread	Switch between threads.
tHRead apply	Apply a command to a list of threads.
tHRead apply all	Apply a command to all threads.
tty	Set the terminal for future runs of the debuggee.
unset environment	Remove a variable from the debuggee's environment.
until	Execute until the program reaches a source line greater than the current one.

17.6.6. Examining the Stack

backtrace	Print a backtrace of all stack frames.
down	Select and print the stack frame called by the current one.
frame	Select and print a stack frame.
return	Make selected stack frame return to its caller.
select-frame	Select a stack frame without printing anything.
up	Select and print the stack frame that called the current one.

17.6.7. Status Inquiries

info	General command for showing information about the debuggee.
macro	Prefix for commands dealing with C preprocessor macros.
show	General command for showing information about the debugger.

17.6.8. Support Facilities

apropos	Search for commands matching a regular expression.
complete	List the command completions for the rest of the line.
define	Define a new command.
document	Document a user-defined command.
dont-repeat	Don't repeat this command. For use in user-defined commands.
down-silently	Same as the down command, but doesn't print messages.
echo	Print a constant string.
else	Provide a list of alternative commands for use with if.
end	End a list of commands or actions.
help	Print list of commands.
if	Execute nested commands once if the conditional expression is nonzero.
make	Run the make program using the rest of the line as arguments.
quit	Exit GDB.
shell	Execute the rest of the line as a shell command.
source	Read commands from a named file.
up-silently	Same as the up command, but doesn't print messages.
while	Execute nested commands while the conditional expression is nonzero.

17.6.9. Text User Interface Commands

focus	Change which window receives the keyboard focus.
layout	Change the layout of the windows in use.
refresh	Clear and redraw the screen.
tui reg	Change which registers are shown in the register window.
update	Update the source window.
winheight	Change the height of a particular window.

17.6.10. Frequently Used Commands

GDB offers a bewilderingly large number of commands, but most users can get by with just a small handful. Table 17-1 lists the ones that you are likely to use most often.

Table 17-1. The top dozen GDB commands

Command	Purpose	Examples
backtrace	Show call trace	ba
break	Set breakpoint at routine entry or at line number	b main
		b parser.c:723
continue	Continue from breakpoint	cont
delete	Remove breakpoint	d 3
finish	Step until end of routine	fin
info breakpoints	List current breakpoints	i br
next	Step to next statement and over routine calls	ne
print	Print expression	print 1.0/3.0
run	(Re)run program, optionally with arguments	ru
		ru -u -o foo < data
step	Step to next statement and into routines	s
x	Examine memory	x/s *environ
until	Continue execution until reaching a source line	until
		until 2367