Commonly used gdb commands
--------------------------
gdb also understands abreviations of commands, so you can just type up to 
the unique part of a command name ("cont" for "continue", or "p" for "print")

help               # List classes of all gdb commands
help <topic>       # Shows help available for topic or command

where (or bt)      # Shows stack: sequence of function calls executed so far
                   # (good for pinpointing location of a program crash)

frame              # Shows all stack frames
frame <frame-num>  # Sets current stack frame to <frame-num>
                   # (useful for checking parameter and argument values)

run                # Starts program execution from the beginning

break <line>       # Sets breakpoint at line number <line>
break <func-name>  # Sets breakpoint at beginning of named function 
continue           # Continues execution from breakpoint

condition <bp-num> <exp>   # Set breakpoint <bp-num> to 
                           # break only when <exp> is true

info break            # Shows current breakpoints
disable [breakpoints] # [bnums ...]  Disable one or more breakpoints
enable [breakpoints]  # [bnums ...]   Enable one or more breakpoints 
clear <line>          # Clears breakpoint at line number <line>
delete <bp-num>       # Deletes breakpoint number <bp-num>
delete                # Deletes all breakpoints

step (or s)           # Executes next line of program (steping into functions)
step <count>          # Executes next <count> lines of program
next (or n)           # Like step, but treats a function call as a single instr
until <line>          # Executes program until line number <line>

print <exp> (or inspect <exp>    # Displays the value of expression <exp>
display <exp>                    # Automatic display of <exp> each time a breakpt hit
whatis <exp>                     # Shows data type of expression <exp>
info locals                      # Shows local variables in current stack frame
set variable <variable> = <exp>  # Sets variable <variable> to expression <exp>

list                  # Lists next few lines of program
list <line>           # Lists lines around line number <line> of program
list <start> <end>    # Lists line numbers <start> through <end>
list <func-name>      # Lists lines at beginning of function <func-name>

help status           # lists a bunch of info X commands, including:
info frame            # list information about the current stack frame
info locals           # list local variable values of current stack frame
info args             # list argument values of current stack frame
info registers        # list register values

quit                  # quits gdb