NAME

       fai-class - define classes using files and scripts.

SYNOPSIS

       fai-class [OPTION] DIRECTORY CLASSFILE

DESCRIPTION

       This command is only called internally by FAI and not directly by the user.

       fai-class  executes  scripts  in  DIRECTORY  to define classes. All classes are written to
       CLASSFILE, each class will be placed on a separate  line.  Use  absolute  paths  for  both
       arguments. All scripts or executables matching "^[0-9][0-9]*" (they start with two digits)
       are executed in alphabetical order. They can define classes by writing the  names  of  the
       classes  to stdout. Classes can be separated by spaces or written one on a line. All lines
       that start with a "#" are comment lines and are ignored.

       Shell scripts that end in ".sh" are sourced and can define classes by setting the variable
       $newclasses. This is useful for scripts where you can't control stdout. Variables that are
       defined in these scripts are available to other scripts in DIRECTORY,  but  they  are  not
       exported  to the shell that calls fai-class. Those scripts can define variables by writing
       definitions to the file $LOGDIR/additional.var, which will be  sourced  in  the  following
       task.

       All   scripts   can  define  additional  classes  by  writing  the  classes  to  the  file
       $LOGDIR/additional-classes. These classes are defined after all scripts are executed. This
       temporary file will be removed after use.

       The  order of the classes is important because it defines the priority of the classes from
       low to high. First, the class DEFAULT is defined, then all scripts are executed to  define
       the  classes.  After that, the classes from the file $LOGDIR/additional-classes are added.
       Subsequently, all classes in the file with the hostname are added. Finally classes defined
       by  the  variable  ADDCLASSES  are  used.  This variable must be a comma separated list of
       classes. You can define this variable on the kernel command line.

       Finally, the class with the hostname and LAST are defined.

       It's important that each line in a file containing a class name ends with  a  newline.  If
       the newline is missing on the last line of a file, this class can't be added.

       The exit code of every script is written to the file status.log in LOGDIR.

OPTIONS

       -d     Create debugging output.

       -h     Show help, version and summary of options.

       -T     Test  if classes in CLASSFILE are defined multiple times. This should never happen.
              The test is executed after the classes are defined.

       -t tmpdir
              The file additional-classes is read from the directory  tmpdir.  Default  value  is
              /tmp/fai/.

       -v     Create verbose output.

EXAMPLES

       In FAI, fai-class is used in the following way:

          # fai-class /fai/class /tmp/fai/FAI_CLASSES

       Then the list of all classes is assigned to the variable classes.

           classes=`cat /tmp/fai/FAI_CLASSES`

EXAMPLES FOR SCRIPTS

       This is the script 01alias:

       #! /bin/sh

       catnc() { # cat but no comment lines
           grep -v "^#" $1
       }
       # echo architecture in upper case
       dpkg --print-architecture | tr /a-z/ /A-Z/
       uname -s | tr /a-z/ /A-Z/

       # all hosts named ant?? use the classes in file anthill
       case $HOSTNAME in
           ant??) catnc anthill ;;
       esac

       # a Beowulf cluster; all nodes except the master node
       # use classes from file class/atoms
       case $HOSTNAME in
           atom00) echo BEOWULF_MASTER ;;
           atom??) catnc atoms ;;
       esac

       # if host belongs to class C subnet 123.45.6.0 use class NET_6
       case $IPADDR in
           123.45.6.*) echo NET_6 ;;
       esac

       Another EXAMPLE:

       The script 24nis:

       #! /bin/sh

       # add NIS and the NIS domain name if YPDOMAIN is defined

       if [ -n "$YPDOMAIN" ];then
          echo "NIS $YPDOMAIN" | tr /.a-z-/ /_A-Z_/
       else
          echo NONIS
       fi

       You can define classes on the kernel command line by appening this to the kernel:

          ADDCLASSES=CLASS1,CLASSX,CLASS3

NOTES

       All class names should be written in uppercase letters (except the class of the hostname).
       Do not use a dash, use an underscore. Only  executable  scripts  in  DIRECTORY  are  used.
       CLASSFILE is removed before writing to it. Scripts should not directly write to CLASSFILE.
       LOGDIR should not be writable for everybody.

SEE ALSO

       This program  is  part  of  FAI  (Fully  Automatic  Installation).  The  FAI  homepage  is
       http://fai-project.org.

AUTHOR

       Written by Thomas Lange <lange@cs.uni-koeln.de>