On an SGI, it is the Alt key. M- is equivalent to ESC , except that you don't release Meta before pressing the next key, which makes it easier and faster than ESC . Whenever your cursor is on one of these prompts you can enter a GDB command. All GDB commands can be abbreviated unless doing so renders them ambiguous. Most of the commonly used commands can be abbreviated to one character.
Arguments listed in brackets are optional.
With no arguments, this lists the command classes. If a class is specified, it will briefly describe commands in that class. If a command is specified, it will provide help on using that command. Each time you recompile your program, you must reload it into GDB using the file command. If you start from within a directory different from the one containing your executable file, you will need to use this command to change to the proper directory.