Quick debugging with gdb

This article introduces common techniques for debugging programs using the GDB command line. The following steps demonstrate how to quickly debug code on the command line:

1. Compile code: Use gcc myprogram.c -g -o myprogram command to compile your C program, and -g option generates debug information.

2. Start GDB: Use the gdb -tui myprogram command to start GDB, and the -tui option enables the text user interface to facilitate viewing of code and debugging information.

3. Set breakpoints: Use the break main command to set breakpoints at main function.

4. Run the program: Use the run command to run the program, and the program will be paused at the breakpoint.

Here are some commonly used GDB commands:

Order	Abbreviation	describe
step	s	Step-by-step to enter the function inside
next	n	Step-by-step, skip function calls
until 123	unt 123	Run to line 123
info locals	i lo	Show local variables in the current scope
print myvar	p myvar	Print the value of the variable myvar
display myvar	disp myvar	Display the value of the variable myvar after each execution
undisplay myvar	und myvar	Stop displaying the value of the variable myvar
set myvar = 0	s myvar = 0	Set the value of the variable myvar to 0
break 456	b 456	Set breakpoint on line 456
info breakpoints	ib	List all breakpoints
delete	d	Delete all breakpoints
list main	l main	Jump to main function
list foo.c:789	l foo.c:789	Jump to line 789 of file foo.c
where	whe	Show the current execution location
kill	k	Terminate the current program execution

In addition, ctrl-l can refresh the screen; focus cmd switches the cursor focus to the command line; focus src switches the cursor focus to the source code display area.

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