GDB Cheetsheet

To debug a source file with gdb, use gcc -g.

List of Everyday Commands

Command	Abbreviation	Description
start	N/A	begin running the program and stop at line 1 in main
step	s	execute the current line of code (this command will step into functions)
next	n	execute the current line of code (this command will not step into functions)
finish	fin	executes the remainder of the current function and returns to the calling function
print [arg]	p	prints the value of the argument
quit	q	exits gdb
break [line num or function name]	b	set a breakpoint at the specified location, use filename.c:linenum to set a breakpoint in a specific file
conditional break (ex: break 3 if n==4)	(ex: b 3 if n==4)	set a breakpoint at the specified location only if a given condition is met
run	r	execute the program until termination or reaching a breakpoint
continue	c	continues the execution of a program that was paused
backtrace	bt	print one line per frame for frames in the stack

Command: info locals

Prints the value of all of the local variables in the current stack frame

Command: command

Executes a list of commands every time a break point is reached. For example: Set a breakpoint:

(gdb) b 73

Type commands followed by the breakpoint number:

(gdb) commands 1

Type the list of commands that you want to execute separated by a new line. After your list of commands, type end and hit Enter.

(gdb) p var1
(gdb) p var2
(gdb) end

Calling a fuction in the symbol list

(gdb) call <name_of_function>

Debugging

Attaching to a process

gdb -p <pid>

Debug with command line arguments

gdb --args /path/to/executable arg1 arg2

Display

Displaying Code

$ gdbtui
$ gdb --tui

Or inside gdb: ^x + o

Displaying Assmbly

(gdb) layout asm

Examine

All examine commands use x

Examine Register

x/i $pc examine the current PC