| Command | Description |
| help | List gdb command topics. |
| help topic-classes | List gdb command within class. |
| help command | Command description. |
| apropos search-word | Search for commands and command topics containing search-word. |
info args
i args | List program command line arguments |
| info breakpoints | List breakpoints |
| info break | List breakpoint numbers. |
| info break breakpoint-number | List info about specific breakpoint. |
| info watchpoints | List breakpoints |
| info registers | List registers in use |
| info threads | List threads in use |
| info set | List set-able option |
| Break and Watch |
|
break funtion-name
break line-number | Suspend program at specified function of line number. |
break +offset
break -offset | Set a breakpoint specified number of lines forward or back from the position at which execution stopped. |
| break filename:function | Don't specify path, just the file name and function name. |
| break filename:line-number | Don't specify path, just the file name and line number. |
| break *address | Suspend processing at an instruction address. Used when you do not have source. |
| break line-number if condition | Where condition is an expression. i.e. x > 5
Suspend when boolean expression is true. |
| break line thread thread-number | Break in thread at specified line number. Use info threads to display thread numbers. |
| tbreak | Temporary break. Break once only. Break is then removed. See "break" above for options. |
| watch condition | Suspend processing when condition is met. i.e. x > 5 |
clear
clear function
clear line-number | Delete breakpoints as identified by command option. |
delete
d | Delete all breakpoints, watchpoints, or catchpoints. |
delete breakpoint-number
delete range | Delete the breakpoints, watchpoints, or catchpoints of the breakpoint ranges specified as arguments. |
disable breakpoint-number-or-range
enable breakpoint-number-or-range | Does not delete breakpoints. Just enables/disables them.
Example:
Show breakpoints: info break
Disable: disable 2-9 |
| enable breakpoint-number once | Enables once |
continue
c | Continue executing until next break point/watchpoint. |
| continue number | Continue but ignore current breakpoint number times. Usefull for breakpoints within a loop. |
| finish | Continue to end of function. |
| Line Execution |
|
step
s
step number-of-steps-to-perform | Step to next line of code. Will step into a function. |
next
n
next number | Execute next line of code. Will not enter functions. |
until
until line-number | Continue processing until you reacha aspecified line number. Also: function name, address, filename:function or filename:line-number. |
stepi
si
nexti
ni | step/next assembly/processor instruction. |
info signals
info handle
handle SIGNAL-NAME option | Perform the following option when signal recieved: nostop, stop, print, noprint, pass/noignore or nopass/ignore |
| where | Shows current line number and which function you are in. |
| Stack |
|
backtrace
bt
bt inner-function-nesting-depth
bt -outer-function-nesting-depth | Show trace of where you are currently. Which functions you are in. Prints stack backtrace. |
| backtrace full | Print values of local variables. |
frame number
f number | Select frame number. |
up number
down number | Move up/down the specified number of frames in the stack. |
| info frame | List address, language, address of arguments/local variables and which registers were saved in frame. |
info args
info locals
info catch | Info arguments of selected frame, local variables and exception handlers. |
| Source Code |
|
list
list line-number
list function
list -
list start#,end#
list filename:function | List source code. |
set listsize count
show listsize | Number of lines listed when list command given. |
directory directory-name
dir directory-name
show directories | Add specified directory to front of source code path. |
| directory | Clear sourcepath when nothing specified. |
| Examine Variables |
|
print variable-name
p variable-name
p file-name::variable-name
p 'file-name'::variable-name | Print value stored in variable. |
| p *array-variable@length | Print first # values of array specified by length. Good for pointers to dynamicaly allocated memory. |
| p/x variable | Print as integer variable in hex. |
| p/d variable | Print variable as a signed integer. |
| p/u variable | Print variable as a un-signed integer. |
| p/o variable | Print variable as a octal. |
p/t variable
x/b address
x/b &variable | Print as integer value in binary. (1 byte/8bits) |
| p/c variable | Print integer as character. |
| p/f variable | Print variable as floating point number. |
| p/a variable | Print as a hex address. |
x/w address
x/4b &variable | Print binary representation of 4 bytes (1 32 bit word) of memory pointed to by address. |
| GDB Modes |
|
| set gdb-option value | Set a GDB option |
set logging on
set logging off
show logging
set logging file log-file | Turn on/off logging. Default name of file is gdb.txt |
set print array on
set print array off
show print array | Default is off. Convient readable format for arrays turned on/off. |
set print array-indexes on
set print array-indexes off
show print array-indexes | Default off. Print index of array elements. |
set print pretty on
set print pretty off
show print pretty | Format printing of C structures. |
set print union on
set print union off
show print union | Default is on. Print C unions. |
set print demangle on
set print demangle off
show print demangle | Default on. Controls printing of C++ names. |
| Start and Stop |
|
run command-line-arguments
run < infile > outfile | Start program execution. The command break main will get you started. Also allows basic I/O redirection. |
| kill | Stopt program execution. |
quit
q | Exit GDB debugger. |
