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CONFIG(8)               FreeBSD System Manager's Manual              CONFIG(8)

NAME
     config - build system configuration files

SYNOPSIS
     config [-gpr] [-d destdir] SYSTEM_NAME

DESCRIPTION
     This is the old version of the config program.  It understands the old
     autoconfiguration scheme used on the HP300, i386, DECstation, and
     derivative platforms.  The new version of config is used with the SPARC
     platform.  Only the version of config applicable to the architecture that
     you are running will be installed on your machine.

     config builds a set of system configuration files from the file
     SYSTEM_NAME which describes the system to configure.  A second file tells
     config what files are needed to generate a system and can be augmented by
     configuration specific set of files that give alternate files for a
     specific machine (see the FILES section below).

     Available options and operands:

     -d destdir       Use destdir as the output directory, instead of the
                      default one.  Note that config does not append
                      SYSTEM_NAME to the directory given.

     -g               Configure a system for debugging.

     -p               Configure a system for profiling; for example, kgmon(8)
                      and gprof(1).  If two or more -p options are supplied,
                      config configures a system for high resolution
                      profiling.

     -r               Remove the old compile directory (see below).

     SYSTEM_NAME      Specify the name of the system configuration file
                      containing device specifications, configuration options
                      and other system parameters for one system
                      configuration.

     config should be run from the conf subdirectory of the system source
     (usually /sys/ARCH/conf), where ARCH represents one of the architectures
     supported by FreeBSD.  config creates the directory
     ../../compile/SYSTEM_NAME or the one given with the -d option as
     necessary and places all output files there.  If the output directory
     already exists and the -r flag was specified, it will be removed first.
     The output of config consists of a number of files; for the i386, they
     are: ioconf.c, a description of what I/O devices are attached to the
     system; Makefile, used by make(1) in building the system; header files,
     definitions of the number of various devices that will be compiled into
     the system.

     After running config, it is necessary to run ``make depend'' in the
     directory where the new makefile was created.  config prints a reminder
     of this when it completes.

     If any other error messages are produced by config, the problems in the
     configuration file should be corrected and config should be run again.
     Attempts to compile a system that had configuration errors are likely to
     fail.

     If the options INCLUDE_CONFIG_FILE is used in the configuration file the
     entire input file is embedded in the new kernel.  This means that
     strings(1) can be used to extract it from a kernel: to extract the
     configuration information, use the command

           strings kernel | grep ___

DEBUG KERNELS
     Traditional BSD kernels compiled without symbols due to the heavy load on
     the system when compiling a ``debug'' kernel.  A debug kernel contains
     complete symbols for all the source files, and enables an experienced
     kernel programmer to analyse the cause of a problem.  The debuggers
     available prior to 4.4BSD-Lite were able to find some information from a
     normal kernel; gdb(1) provides very little support for normal kernels,
     and a debug kernel is needed for any meaningful analysis.

     For reasons of history, time and space, building a debug kernel is not
     the default with FreeBSD: a debug kernel takes up to 30% longer to build
     and requires about 30 MB of disk storage in the build directory, compared
     to about 6 MB for a non-debug kernel.  A debug kernel is about 11 MB in
     size, compared to about 2 MB for a non-debug kernel.  This space is used
     both in the root file system and at run time in memory.  Use the -g
     option to build a debug kernel.  With this option, config causes two
     kernel files to be built in the kernel build directory:

     +o   kernel.debug is the complete debug kernel.

     +o   kernel is a copy of the kernel with the debug symbols stripped off.
         This is equivalent to the normal non-debug kernel.

     There is currently little sense in installing and booting from a debug
     kernel, since the only tools available which use the symbols do not run
     on-line.  There are therefore two options for installing a debug kernel:

     +o   ``make install'' installs kernel in the root file system.

     +o   ``make install.debug'' installs kernel.debug in the root file system.

FILES
     /sys/conf/files                                            list of common
                                                                files system
                                                                is built from
     /sys/conf/Makefile.ARCH                                    generic
                                                                makefile for
                                                                the ARCH
     /sys/conf/files.ARCH                                       list of ARCH
                                                                specific files
     /sys/ARCH/conf/files.SYSTEM_NAME                           list of files
                                                                specific to
                                                                SYSTEM_NAME on
                                                                ARCH
     /sys/compile/SYSTEM_NAME                                   default kernel
                                                                build
                                                                directory for
                                                                system
                                                                SYSTEM_NAME.

SEE ALSO
     The SYNOPSIS portion of each device in section 4.

     Building 4.3 BSD UNIX System with Config.

BUGS
     The line numbers reported in error messages are usually off by one.

HISTORY
     The config command appeared in 4.1BSD.

FreeBSD 11.0-PRERELEASE          July 4, 2001          FreeBSD 11.0-PRERELEASE

NAME | SYNOPSIS | DESCRIPTION | DEBUG KERNELS | FILES | SEE ALSO | BUGS | HISTORY

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