Debuggers
GDB commands by function - simple guide
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More important commands have a (*) by them.
# Startup
% gdb -help # print startup help, show switches
* gdb set disassembly-flavor intel # print in intel mode
*% gdb object # normal debug
*% gdb object core # core debug (must specify core file)
%% gdb object pid # attach to running process
% gdb # use file command to load object
# Help
*(gdb) help # list command classes
(gdb) help running # list commands in one command class
(gdb) help run # bottom-level help for a command "run"
(gdb) help info # list info commands (running program state)
(gdb) help info line # help for a particular info command
(gdb) help show # list show commands (gdb state)
(gdb) help show commands # specific help for a show command
# Breakpoints
*(gdb) break main # set a breakpoint on a function
*(gdb) break 101 # set a breakpoint on a line number
*(gdb) break basic.c:101 # set breakpoint at file and line (or function)
*(gdb) info breakpoints # show breakpoints
(gdb) delete 1 # delete a breakpoint by number
(gdb) delete # delete all breakpoints (prompted)
(gdb) clear # delete breakpoints at current line
(gdb) clear function # delete breakpoints at function
(gdb) clear line # delete breakpoints at line
(gdb) disable 2 # turn a breakpoint off, but dont remove it
(gdb) enable 2 # turn disabled breakpoint back on
(gdb) tbreak function|line # set a temporary breakpoint
(gdb) commands break-no ... end # set gdb commands with breakpoint
(gdb) ignore break-no count # ignore bpt N-1 times before activation
(gdb) condition break-no expression # break only if condition is true
(gdb) condition 2 i == 20 # example: break on breakpoint 2 if i equals 20
(gdb) watch expression # set software watchpoint on variable
(gdb) info watchpoints # show current watchpoints
# Running the program
*(gdb) run # run the program with current arguments
*(gdb) run args redirection # run with args and redirection
(gdb) set args args... # set arguments for run
(gdb) show args # show current arguments to run
*(gdb) cont # continue the program
*(gdb) step # single step the program; step into functions
(gdb) step count # singlestep \fIcount\fR times
*(gdb) next # step but step over functions
(gdb) next count # next \fIcount\fR times
*(gdb) CTRL-C # actually SIGINT, stop execution of current program
*(gdb) attach process-id # attach to running program
*(gdb) detach # detach from running program
*(gdb) finish # finish current functions execution
(gdb) kill # kill current executing program
# Stack backtrace
*(gdb) bt # print stack backtrace
(gdb) frame # show current execution position
(gdb) up # move up stack trace (towards main)
(gdb) down # move down stack trace (away from main)
*(gdb) info locals # print automatic variables in frame
(gdb) info args # print function parameters
# Browsing source
*(gdb) list 101 # list 10 lines around line 101
*(gdb) list 1,10 # list lines 1 to 10
*(gdb) list main # list lines around function
*(gdb) list basic.c:main # list from another file basic.c
*(gdb) list - # list previous 10 lines
(gdb) list *0x22e4 # list source at address
(gdb) cd dir # change current directory to \fIdir\fR
(gdb) pwd # print working directory
(gdb) search regexpr # forward current for regular expression
(gdb) reverse-search regexpr # backward search for regular expression
(gdb) dir dirname # add directory to source path
(gdb) dir # reset source path to nothing
(gdb) show directories # show source path
# Browsing Data
*(gdb) print expression # print expression, added to value history
*(gdb) print/x expressionR # print in hex
(gdb) print array[i]@count # artificial array - print array range
(gdb) print $ # print last value
(gdb) print *$->next # print thru list
(gdb) print $1 # print value 1 from value history
(gdb) print ::gx # force scope to be global
(gdb) print 'basic.c'::gx # global scope in named file (>=4.6)
(gdb) print/x &main # print address of function
(gdb) x/countFormatSize address # low-level examine command
(gdb) x/x &gx # print gx in hex
(gdb) x/4wx &main # print 4 longs at start of \fImain\fR in hex
(gdb) x/gf &gd1 # print double
(gdb) help x # show formats for x
*(gdb) info locals # print local automatics only
(gdb) info functions regexp # print function names
(gdb) info variables regexp # print global variable names
*(gdb) ptype name # print type definition
(gdb) whatis expression # print type of expression
*(gdb) set variable = expression # assign value
(gdb) display expression # display expression result at stop
(gdb) undisplay # delete displays
(gdb) info display # show displays
(gdb) show values # print value history (>= gdb 4.0)
(gdb) info history # print value history (gdb 3.5)
# Object File manipulation
(gdb) file object # load new file for debug (sym+exec)
(gdb) file # discard sym+exec file info
(gdb) symbol-file object # load only symbol table
(gdb) exec-file object # specify object to run (not sym-file)
(gdb) core-file core # post-mortem debugging
# Signal Control
(gdb) info signals # print signal setup
(gdb) handle signo actions # set debugger actions for signal
(gdb) handle INT print # print message when signal occurs
(gdb) handle INT noprint # dont print message
(gdb) handle INT stop # stop program when signal occurs
(gdb) handle INT nostop # dont stop program
(gdb) handle INT pass # allow program to receive signal
(gdb) handle INT nopass # debugger catches signal; program doesn't
(gdb) signal signo # continue and send signal to program
(gdb) signal 0 # continue and send no signal to program
# Machine-level Debug
(gdb) info registers # print registers sans floats
(gdb) info all-registers # print all registers
(gdb) print/x $pc # print one register
(gdb) stepi # single step at machine level
(gdb) si # single step at machine level
(gdb) nexti # single step (over functions) at machine level
(gdb) ni # single step (over functions) at machine level
(gdb) display/i $pc # print current instruction in display
(gdb) x/x &gx # print variable gx in hex
(gdb) info line 22 # print addresses for object code for line 22
(gdb) info line *0x2c4e # print line number of object code at address
(gdb) x/10i main # disassemble first 10 instructions in \fImain\fR
(gdb) disassemble addr # dissassemble code for function around addr
# History Display
(gdb) show commands # print command history (>= gdb 4.0)
(gdb) info editing # print command history (gdb 3.5)
(gdb) ESC-CTRL-J # switch to vi edit mode from emacs edit mode
(gdb) set history expansion on # turn on c-shell like history
(gdb) break class::member # set breakpoint on class member. may get menu
(gdb) list class::member # list member in class
(gdb) ptype class # print class members
(gdb) print *this # print contents of this pointer
(gdb) rbreak regexpr # useful for breakpoint on overloaded member name
# Miscellaneous
(gdb) define command ... end # define user command
*(gdb) RETURN # repeat last command
*(gdb) shell command args # execute shell command
*(gdb) source file # load gdb commands from file
*(gdb) quit # quit gdb
Última actualización 1yr ago