You can always ask GDB itself for information on its commands, using the command, help.
help
h
You can use help
(abbreviated h)
with no arguments to display a short list of named classes of commands
like the following example output.
(gdb) help List of classes of commands: running -- Running the program stack -- Examining the stack data -- Examining data breakpoints -- Making program stop at certain points files -- Specifying and examining files status -- Status inquiries support -- Support facilities user-defined -- User-defined commands aliases -- Aliases of other commands obscure -- Obscure features Type help followed by a class name for a list of commands in that class. Type help followed by command name for full documentation. Command name abbreviations are allowed if unambiguous. (gdb)
help class
Using one of the general help
classes as an argument, you can get a list of the individual commands in
that class. For example, here is the help
display for the class, status:
(gdb) help status Status inquiries. List of commands: show -- Generic command for showing things set with set info -- Generic command for printing status Type help followed by command name for full documentation. Command name abbreviations are allowed if unambiguous. (gdb)
help
command
With a command name as help
argument, GDB displays a short paragraph on how to use that command.
complete
args
The complete
args
command lists all the possible completions for the beginning of a command.
Use args
to specify the beginning of the command you want completed. For example:
complete i
results in the following.
info
inspect
ignore
This command is intentionally for use by GNU Emacs.
In addition to help, you can use the GDB commands info and show to inquire about the state of your program, or the state of GDB itself. Each command supports many topics of inquiry; this manual introduces each of them in the appropriate context. The listings under info and under show in the Index point to all the subcommands. See Index in Debugging with GDB.
info
This command (abbreviated i)
is for describing the state of your program. For example, you can list
the arguments given to your program with info
args,
list the registers currently in use with info
registers, or
list the breakpoints you have set with info
breakpoints. You
can get a complete list of the info subcommands with help
info.
set
You can assign the result of an expresson to an environment variable with
set.
For example, you can set the GDB prompt to a $-sign
with set
prompt $.
show
In contrast to info,
show
is for describing the state of GDB itself. You can change most of the things
you can show, by using the related command, set;
for example, you can control what number system is used for displays with
set radix,or
simply inquire which is currently in use with show
radix.
To display all the settable parameters and their current values, you can use show with no arguments; you may also use info set. Both commands produce the same display.
The following are three miscellaneous show subcommands, all of which are exceptional in lacking corresponding set commands.
show version
Show what version of GDB is running. You should include this information
in GDB bug reports. If multiple versions of GDB are in use at your site,
you may occasionally want to determine which version of GDB you are running;
as GDB evolves, new commands are introduced, and old ones may wither away.
The version number is also announced when you start GDB.
show copying
Display information about permission for copying GDB.
show warranty
Display the GNU NO WARRANTY statement (see Figure
2 in GDB Graphical User Interface.