6.0;xsubs (execute_subsystem), revision 7.0, 83/10/06
XSUBS (EXECUTE_SUBSYSTEM) -- Execute a Shell script protected subsystem manager.
usage:  XSUBS pathname [args...]


FORMAT

  XSUBS pathname [args...]


  Once  a  protected  subsystem,  a  subsystem  manager(s), and a subsystem data
  object(s) exist, any user can execute the manager program.  To  run  a  binary
  manager  program,  you  simply  execute  the  program.   To run a Shell script
  manager program, you must use the XSUBS command.  Note that in  order  to  see
  the  name  of  a  subsystem  created  on  another node, you must copy the file
  /SYS/SYBSYS/Subsystem_name to your node.  If you do not copy  this  file,  you
  can  use the subsystem managers to operate on the objects, but when you ask to
  display the name of the subsystem, you will get  an  error  message  like  the
  following:

  $ subs //fred/jtj/com/top_secret
  ?(subs) Can't show subsystem manager type for "//zoid/jtj/com/top_secret"
          - subsystem name not found  (US/aclm)
  $


ARGUMENTS

  pathname
  (required)         Specify Shell script containing the subsystem manager to be
                     executed.   Note that this script must contain the commands
                     SUBS -UP and SUBS -DOWN in order  to  enter  and  exit  the
                     subsystem.

  args ...
  (optional)         Specify arguments to be passed to the Shell script.

                     Default if omitted:  no arguments passed


EXAMPLES

  Suppose  you  have  an  append-only list that you wish to protect.  Anyone can
  read the list, and append to the list, but no  one  can  overwrite  previously
  existing  contents.    Assume that the subsystem 'append_only' already exists.
  Then the 'APP' Shell script, which appends standard input  to  an  append-only
  file, would look like this:

    # APP --- append to an append_only file
    SUBS -UP
    CATF >>^1       # append to the file passed as first argument
    SUBS -DOWN

  To make APP a manager of the 'append_only' subsystem, do

    ENSUBS append_only          # enter subsystem
    SUBS APP append_only -MGR
    *** EOF ****

  A run of APP would look like this:

    XSUBS APP aofile            # execute APP on 'aofile'
    this is the stuff that is appended
    *** EOF ***


RELATED TOPICS

  More information is available.  Type:

  - HELP PROTECTED_SUBSYSTEMS
    for a list of Shell commands for use with protected subsystems.

  - HELP PROTECTION PROTECTED_SUBSYSTEMS
    for a detailed description of protected subsystems.