gdb

1. Start gdb on an executable file:$ gdb abc     // file "abc" is an executable file or a core file.
   OR
$ gdb
  (gdb) file  abc   // open executable file "abc"

2. Configuration of gdb:   (gdb) set linesize 30    // Set number of lines displayed by list command.
  (gdb) set prompt (gdb)$  // set gdb prompt instead of default (gdb)
  (gdb) show commands      // Show last 10 commands in history
  (gdb) show commands  30  // Show last 10 commands around line 30 in history
  (gdb) show commands  +   // Show next 10 commands.

3. Use shell commands:    Only cd, pwd and make can be used directly in gdb, rest of commands should
   be prefixed with shell.
  (gdb) cd  aFolder  
  (gdb) pwd           
  (gdb) make
  (gdb) shell ls    // Run ls command

4. GDB commands for debugging purpose. a) Run:
   (gdb) run               // Run program
   (gdb) run arg1 arg2     // Run program with arguments
b) Set Breakpoint/Stop Sign:
   (gdb) b   location      // Set a stop sign at aLocation.
   (gdb) watch  theVar     // watch is a special stop sign. Stops when theVar's value is changing.
   (gdb) rwatch theVar     // Stops when theVar is read from.
   (gdb) awatch theVar     // Stops when theVar is read from or written to.
   (gdb) advance aLocation // Continue to this temporary aLocation.
c) Examine variables:
   (gdb) p     theVar   // Display value of theVar.
   (gdb) disp  theVar   // Display value of theVar EACH TIME program STOPs.
   (gdb) info disp      // For instance, find display# for theVar is 3.
   (gdb) undisp  3      // Remove display of theVar whose display# is 3.
   (gdb) set variable theVar = 100  // Change theValue's value to 100.
   (gdb) set (theVar = 100)         // Change theValue's value to 100.
d) Stop and Go.
   <<STOPS>>
   (gdb) when arriaved at a stop sign    // Pause the execution of program.
   (gdb) b 17      // Set a stop sign at line 17.
   (gdb) i b       // List all the stop signs.
   (gdb) CTRL-C    // Pause the execution of program.
                   // If followed by "bt" command, you will know where you are.
   <<GOES>>
   (gdb) next      // Move on to the next statement treating a function as one statement.
   (gdb) step      // Move on to the next statement treating a function as multiple statements.
   (gdb) finish    // Exit a function body but NOT resume the execution.
   (gdb) continue        // Resume the execution of program at the current place.
   (gdb) jump  aLocation // Resume execution at aLocation. (similar to GOTO)
e) Stack (function stack)
   (gdb) bt       // Print all the frames in stack.
                  // Also tells which function you are in (where you are.).
   (gdb) up       // Go to one-level outer function.
   (gdb) down     // Go to one-level inner function.
   (gdb) frame 3  // Go to frame 3
   (gdb) info args   // Display args for the current frame/function.
   (gdb) info locals // Display local variables for the current frame/function.
   (gdb) info reg           // Display register
   (gdb) info all-reg       // Display all registers
   (gdb) info reg general   // Display general register
   (gdb) info reg float     // Display float register
   (gdb) info reg    // Display local variables for the current frame/function.