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(grub.info)Command interface

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Enter node , (file) or (file)node

The generic interface for built-ins
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   GRUB built-in commands are defined in a uniformal interface, whether
they are menu-specific or can be used anywhere. The definition of a
builtin command consists of two parts: the code itself and the table of
the information.

   The code must be a function which takes two arguments, a command-line
string and flags, and returns an `int' value. The "flags" argument
specifies how the function is called, using a bit mask. The return
value must be zero if successful, otherwise non-zero. So it is normally
enough to return ERRNUM.

   The table of the information is represented by the structure `struct
builtin', which contains the name of the command, a pointer to the
function, flags, a short description of the command and a long
description of the command. Since the descriptions are used only for
help messages interactively, you don't have to define them, if the
command may not be called interactively (such as `title').

   The table is finally registered in the table BUILTIN_TABLE, so that
`run_script' and `enter_cmdline' can find the command. See the files
`cmdline.c' and `builtins.c', for more details.