rfc2839.txt

RFC 的详细文档！

    . Reception of files into directories or devices to which write
      access is allowed.

    . The ability to display a file on the client's screen.

    . Ability to list files.

    . Ability to change its working (default) directory.

    . Ability to delete files to which write or delete access is
      allowed.

    . Ability to rename and copy files

    . Ability to create and remove directories.

    . The ability to route received files to a specified printer, or to
      send them as email to a specified address list.

    . Client control of server parameter settings, within limits
      established by the server system administrator.

    . Transmission of variables from client to server or vice versa.

    . Remote and local script execution.

    . Remote and local procedure execution.








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RFC 2839                Internet Kermit Service                 May 2000


   File transfer features include:

    . Kermit text-mode transfers incorporate not only record-format
      conversion, but also character-set translation;

    . Kermit can switch automatically between text and binary mode on a
      per-file basis when sending groups of files.

    . A selection of file collision options, including "make backup copy
      of existing file and accept incoming file", "reject incoming
      file", "accept incoming file only if newer than existing file",
      etc.

    . Numerous methods for selecting the files to be transferred,
      including pattern matching, lists of filenames (or patterns),
      exception lists, date and/or size ranges, etc.

    . Filename conversion and file renaming.

    . Automatic directory creation if elected and enabled.

    . Standard mechanisms for directory traversal, allowing transmission
      of entire directory trees or other file hierarchies even between
      unlike file systems such as VMS, UNIX, and Windows.

    . Atomic file movement: optionally, the source file can be deleted
      (or renamed, or moved) when and only when it has been transferred
      successfully.

    . Kermit can retain file attributes including time stamps and
      permissions (at the user's or system administrator's discretion),
      even between unlike platforms;

    . Recovery of interrupted transfers from the point of failure.

    . File-transfer pipes and filters.

   Script programming features include:

    . Macros with parameter substitution.

    . Built-in and user-defined variables and arrays, with global or
      local scope.








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    . Built-in and user-defined functions.  Built-in functions include:

          - String functions
          - Arithmetic functions
          - Date / time functions
          - File functions

    . Input search for multiple simultaneous targets.

    . IF-ELSE, WHILE, FOR, SWITCH, GOTO, C-like block structure.

    . Every command returns a completion status that may be tested and
      used as a basis for subsequent actions.

5.3. User Interface

   The Internet Kermit Service uses the Kermit command and script
   language, as implemented in Columbia University's C-Kermit
   communication software [CKB].  This program and its command language
   are portable to all known varieties of UNIX, as well as to Windows
   95/98/NT, OS/2, Digital (Open)VMS, Stratus VOS, Data General AOS/VS,
   Plan 9, OS-9, QNX, the Commodore Amiga, and other platforms.  The
   C-Kermit command language is a superset of that of other Kermit
   software programs including MS-DOS Kermit for DOS and Windows 3.x,
   IBM Mainframe Kermit for VM/CMS, MVS/TSO, CICS, and MUSIC, PDP-11
   Kermit for RT-11, RSTS/E, RSX-11, and IAS, and dozens of other Kermit
   programs.

   It is far beyond the scope of this document to enumerate, let alone
   describe, the commands and services of C-Kermit; this is the subject
   of a 600-page book [CKB], augmented by hundreds of pages of online
   material.  A brief overview is included here.

   Commands are based on English words.  There is no plan at present to
   support other natural languages (Italian, Portuguese, Norwegian,
   Russian, Hebrew, Japanese, Cherokee, etc) as alternative bases for
   command words, since this would reduce the portability of scripts.
   However, since the command language includes a macro capability,
   macros may be defined to provide selected commands in different
   languages if desired.

   Certain commands can apply either locally or remotely, for example
   "CD" (Change Directory).  The convention is to prefix the command
   with the word REMOTE if it is to apply remotely.  Example: "cd foo"
   changes to the "foo" directory on the computer where the command was
   given; "remote cd foo" sends a Kermit packet to the Kermit server
   requesting it to change its directory to "foo".  The commands in this
   category include:



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     ASSIGN <variable> <value>      Assign a value to a variable.
     CD <directory>                 Change working directory.
     COPY <files> <destination>     Copy file(s)
     DELETE <files>                 Delete file(s)
     DIRECTORY [ <pattern> ]        List file(s)
     EXIT                           Exit
     HELP [ <topic-or-command> ]    Display help text
     MKDIR <directory>              Create a directory
     PRINT <files>                  Print file(s)
     PWD                            Print working directory
     RENAME <old> <new>             Rename file(s)
     RMDIR <directory>              Remove a directory
     SET <parameter> <value>        Change a parameter's value
     TYPE <file>                    Display the contents of a file

   As a convenience, REMOTE commands also have short synonyms: RASSIGN,
   RCD, RCOPY, RDELETE, and so forth.

   The basic file transfer commands are:

     SEND [ modifiers ] <files>    Send file(s) (to server)
     GET [ modifiers ] <files>     Get file(s) (from server)

   These commands take a file name, pattern, or list, plus various
   optional modifiers, including transfer mode specifiers (text,
   binary), file selectors (date, size, exception list), aliasing, name
   and path options, disposition specifiers, and so on.

   In addition to the commands listed above, the following commands are
   sent by the client to the server:

     REMOTE QUERY                   Get value of variable or procedure
     BYE                            Log out and close the connection
     FINISH                         Request the server leave server mode

   Like all Kermit client/server commands, these can be disabled if
   desired.

   Of course there are numerous other commands with purely local effect,
   such as the many scripting commands.  These, plus all the commands
   above, are fully documented in [CKB].  The repertoire grows over
   time, but never in a way that invalidates existing scripts.

   The system administrator can allow or forbid access to any of these
   features, and to the command language as a whole.  In the latter
   case, the IKS may be accessed only as a Kermit server, by giving
   commands to the client.




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6. REFERENCES

   [TKO] Altman, J. and F. da Cruz, "Telnet Kermit Option", RFC 2840,
         May 2000.

   [BCP] Bradner, S., "Key words for use in RFCs to Indicate Requirement
         Levels", BCP 14, RFC 2119, March 1997.

   [KER] da Cruz, Frank, "Kermit, A File Transfer Protocol", Digital
         Press/ Butterworth Heinemann, Newton, MA (1987).  379 pages,
         ISBN 0-932376-88-6.

   [CKB] da Cruz, Frank, and Christine M. Gianone, "Using C-Kermit",
         Second Edition, Digital Press / Butterworth-Heinemann, Woburn,
         MA (1997).  622 pages, ISBN 1-55558-164-1.

   [CMG] Gianone, Christine M., "Using MS-DOS Kermit", Second Edition,
         Digital Press / Butterworth-Heinemann, Woburn, MA (1992). 345
         pages, ISBN 1-55558-082-3.

   [K95] Gianone, Christine M., and Frank da Cruz, "Kermit 95", Manning
         Publications, Greenwich CT, (1996). 88 pages, ISBN 1-884777-
         14-7.

   [PRF] Huggins, James K., "Kermit Protocol - Formal Specification and
         Verification", in Boerger, E., "Specification and Validation
         Methods", Oxford University Press (1995).  ISBN 0-19-853854-5.

   [FTP] Postel, J. and J. Reynolds, "File Transfer Protocol (FTP)", STD
         9, RFC 959, October 1985.

   [TEL] Postel, J. and J. Reynolds, "Telnet Protocol Specification",
         STD 8, RFC854, May 1983, et seq.; "Telnet Option
         Specification", STD 8, RFC855, May 1983, et seq.

   [IAN] Internet Assigned Numbers Authority:
         http://www.iana.org/numbers.html
         http://www.iana.org/assignment/port-numbers













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7. AUTHORS' ADDRESSES

   Frank da Cruz

   EMail: [e-mail]


   Jeffrey E. Altman

   EMail:[e-mail]


   The Kermit Project
   Columbia University
   612 West 115th Street
   New York NY 10025-7799
   USA
   http://www.columbia.edu/kermit/
   http://www.kermit-project.org/
































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8.  Full Copyright Statement

   Copyright (C) The Internet Society (2000).  All Rights Reserved.

   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published
   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph are
   included on all such copies and derivative works.  However, this
   document itself may not be modified in any way, such as by removing
   the copyright notice or references to the Internet Society or other
   Internet organizations, except as needed for the purpose of
   developing Internet standards in which case the procedures for
   copyrights defined in the Internet Standards process must be
   followed, or as required to translate it into languages other than
   English.

   The limited permissions granted above are perpetual and will not be
   revoked by the Internet Society or its successors or assigns.

   This document and the information contained herein is provided on an
   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Acknowledgement

   Funding for the RFC Editor function is currently provided by the
   Internet Society.



















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