starter GDB cheat sheet

gdb.md

GDB Cheat Sheet

Starting & Running

Command	Description
gdb <program>	Start GDB with the specified program.
gdb -q	Start quietly (no intro).
run [args]	Run program with optional args.
start	Run until main() and break.
attach <pid>	Attach to a running process.
detach	Detach from process.
quit	Exit GDB.

Breakpoints

Command	Description
break <function>	Break at function.
break <file:line>	Break at file:line.
break *<address>	Break at memory address.
info breakpoints	List breakpoints.
delete <n>	Delete breakpoint n.
disable <n>	Disable breakpoint n.
enable <n>	Enable breakpoint n.
condition <n> <expr>	Breakpoint n triggers only if expr is true.

Stepping & Continuing

Command	Description
next / n	Step over (don’t enter functions).
step / s	Step into function.
finish	Run until current function returns.
continue / c	Resume execution.
until <line>	Continue until line reached.

Examining State

Command	Description
print <expr>	Print expression.
display <expr>	Auto-print expr each stop.
undisplay <n>	Remove auto-print n.
backtrace / bt	Show call stack.
frame <n>	Switch to frame n.
info locals	Show local variables.
info args	Show function arguments.
x/<nfu> <addr>	Examine memory (n=repeat count, f=format, u=unit size). Example: x/16xb $sp.

Changing State

Command	Description
set var <expr>=<val>	Change variable value.
return <expr>	Force current function to return expr.
jump <line>	Jump to line.

Program Control

Command	Description
kill	Stop program.
signal <sig>	Send signal to program.
handle <sig> <action>	Control how GDB handles signals.

Misc

Command	Description
info registers	Show CPU registers.
info threads	List threads.
thread <n>	Switch to thread n.
watch <expr>	Break when expr changes.
help	Show help.
apropos <keyword>	Search help topics.

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Tip: Use tab completion and help <command> inside GDB for details.