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关于SHELL方面的

			Shell Directory README

This directory contains the source for the Xinu shell and sample set
of commands.  When make runs, it produces a library (libS.a) that contains
object files for all commands (x_zzz.c).  It then compiles the shell
(addarg.c ascdate.c login.c shell.c) and links it together with commands
that are referenced to produce a single object file (sh.o).

Files cmd.h and shell.h are linked to ../../h/cmd.h and ../../h/shell.h
to make it convenient to share them between the rest of the kernel and
files here.

To change the command set, edit cmd.h and change the list defined by
CMDS.  Each entry consists of a command name to recognize, a Boolean
that specifies whether the command should be run as a builtin (as opposed
to running it as a separate process), and a procedure to call for that
command.  File cmd.h also contains extern declarations for all of the
procedures mentioned in CMDS.

Note 1:	Some commands cannot be inserted and/or removed without modifying
	the rest of the kernel.  In particular, the ruptime command cannot
	be used unless the kernel is compiled to execute the rwho daemon.

Note 2:	The system comes on the distribution tape with all the commands
	configured in it.  This leaves very little of the LSI 11's 16-bit
	address space for modifications or additions.  We suggest removing
        commands like create, snap, rls, and echo.  You can gain considerably
	more space by removing ruptime, uptime, and the rwho daemons.