Getting help
============
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:
(gdb) help
List of classes of commands:
aliases -- Aliases of other commands
breakpoints -- Making program stop at certain points
data -- Examining data
files -- Specifying and examining files
internals -- Maintenance commands
obscure -- Obscure features
running -- Running the program
stack -- Examining the stack
status -- Status inquiries
support -- Support facilities
tracepoints -- Tracing of program execution without
stopping the program
user-defined -- User-defined commands
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:
info -- Generic command for showing things
about the program being debugged
show -- Generic command for showing things
about the debugger
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.
`apropos ARGS'
The `apropos ARGS' command searches through all of the GDB
commands, and their documentation, for the regular expression
specified in ARGS. It prints out all matches found. For example:
apropos reload
results in:
set symbol-reloading -- Set dynamic symbol table reloading
multiple times in one run
show symbol-reloading -- Show dynamic symbol table reloading
multiple times in one run
`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:
if
ignore
info
inspect
This is intended 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 sub-commands.
Note:Index.
`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'
sub-commands with `help info'.
`set'
You can assign the result of an expression 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.
Here 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 need to determine which version of
GDB you are running; as GDB evolves, new commands are introduced,
and old ones may wither away. Also, many system vendors ship
variant versions of GDB, and there are variant versions of GDB in
GNU/Linux distributions as well. The version number is the same
as the one announced when you start GDB.
`show copying'
Display information about permission for copying GDB.
`show warranty'
Display the GNU "NO WARRANTY" statement, or a warranty, if your
version of GDB comes with one.