ckcbwr.txt

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                      C-Kermit 8.0 General Hints and Tips

     Frank da Cruz
     [1]The Kermit Project, [2]Columbia University

   As of: C-Kermit 8.0.211, 17 March 2003
   This page last updated: Sat Apr 10 16:37:37 2004 (New York USA Time)

     IF YOU ARE READING A PLAIN-TEXT version of this document, it is a
     plain-text dump of a Web page. You can visit the original (and
     possibly more up-to-date) Web page here:

  [3]http://www.columbia.edu/kermit/ckcbwr.html

   This document contains platform-independent C-Kermit hints and tips.
   Also see the platform-specific C-Kermit hints and tips document for
   your platform, for example:

  [4]http://www.columbia.edu/kermit/ckubwr.html

   for Unix. This document also applies to [5]Kermit 95 for Windows,
   which is based on C-Kermit.

   [ [6]C-Kermit ] [ [7]TUTORIAL ]
    ________________________________________________________________________

  CONTENTS

   0. [8]PATCHES
   1. [9]INCOMPATIBLE CHANGES
   2. [10]THE C-KERMIT COMMAND PARSER
   3. [11]MULTIPLE SESSIONS
   4. [12]NETWORK CONNECTIONS
   5. [13]MODEMS AND DIALING
   6. [14]DIALING HINTS AND TIPS
   7. [15]TERMINAL SERVERS
   8. [16]TERMINAL EMULATION
   9. [17]KEY MAPPING
  10. [18]FILE TRANSFER
  11. [19]SCRIPT PROGRAMMING
    ________________________________________________________________________

  0. PATCHES

   [ [20]Top ] [ [21]Contents ] [ [22]Next ]

   Source-level patches for C-Kermit 8.0.211:

     (None)
    ________________________________________________________________________

  1. INCOMPATIBLE CHANGES

   [ [23]Top ] [ [24]Contents ] [ [25]Next ]

   These are not necessarily exhaustive lists.

  1.1. C-Kermit 6.0

   C-Kermit 6.0 was released 6 September 1996 and is completely
   documented in [26]Using C-Kermit, 2nd Edition. The following
   incompatible changes were made in C-Kermit 6.0:

     * Unless you tell C-Kermit otherwise, if a serial or network
       connection seems to be open, and you attempt to EXIT or to open a
       new connection, C-Kermit warns you that an active connection
       appears to be open and asks you if you really want to close it. If
       you do not want these warnings, add SET EXIT WARNING OFF to your
       customization file or script, or give this command at the prompt.
     * The default for SET { SEND, RECEIVE } PATHNAMES was changed from
       ON to OFF, to prevent unexpected creation of directories and
       depositing of incoming files in places you might not know to look.
     * The default for SET FILE INCOMPLETE was changed from DISCARD to
       KEEP to allow for file transfer recovery.
     * The default file-transfer block-check is now 3, rather than 1. If
       the other Kermit does not support this, the two will drop back to
       type 1 automatically unless the other Kermit fails to follow the
       protocol specification.
     * The default flow-control is now "auto" ("do the right thing for
       each type of connection"), not Xon/Xoff.
     * Backslash (\) is no longer a command continuation character. Only
       - (hyphen, dash) may be used for this in C-Kermit 6.0 and later.
     * Negative INPUT timeout now results in infinite wait, rather than 1
       second.

  1.2. C-Kermit 7.0

   C-Kermit 7.0 was released 1 January 2000. Its new features are
   documented in the C-Kermit 7.0 Supplement,
   [27]http://www.columbia.edu/kermit/ckermit2.html. The following
   incompatible changes were made in C-Kermit 7.0:
     * The "multiline GET" command is gone. Now use either of the
       following forms instead:
  get remote-name local-name
  get /as-name:local-name remote-name
       If either name contains spaces, enclose it in braces (or, in
       C-Kermit 8.0, doublequotes).
     * To include multiple file specifications in a GET command, you must
       now use MGET rather than GET:
  mget file1 file2 file3 ...
     * C-Kermit 7.0 and later use FAST Kermit protocol settings by
       default. This includes "unprefixing" of certain control
       characters. Because of this, file transfers that worked with
       previous releases might not work in the new release especially
       against a non-Kermit-Project Kermit protocol implementation (but
       it is more likely that they will work, and much faster). If a
       transfer fails, you'll get a context-sensitive hint suggesting
       possible causes and cures. Usually SET PREFIXING ALL does the
       trick.
     * By default C-Kermit 7.0 and later send files in text or binary
       mode by looking at each file to see which is the appropriate mode.
       To restore the previous behavior, put SET TRANSFER MODE MANUAL and
       the desired SET FILE TYPE (TEXT or BINARY) in your C-Kermit
       initialization file.
     * The RESEND and REGET commands automatically switch to binary mode;
       previously if RESEND or REGET were attempted when FILE TYPE was
       TEXT, these commands would fail immediately, with a message
       telling you they work only when the FILE TYPE is BINARY. Now they
       simply do this for you.
     * SET PREFIXING CAUTIOUS and MINIMAL now both prefix linefeed (10
       and 138) in case rlogin, ssh, or cu are "in the middle", since
       otherwise <LF>~ might appear in Kermit packets, and this would
       cause rlogin, ssh, or cu to disconnect, suspend,escape back, or
       otherwise wreck the file transfer. Xon and Xoff are now always
       prefixed too, even when Xon/Xoff flow control is not in effect,
       since unprefixing them has proven dangerous on TCP/IP connections.
     * In UNIX, VMS, Windows, and OS/2, the DIRECTORY command is built
       into C-Kermit itself rather than implemented by running an
       external command or program. The built-in command might not behave
       the way the platform-specific external one did, but many options
       are available for customization. Of course the underlying
       platform-specific command can still be accessed with "!", "@", or
       "RUN" wherever the installation does not forbid. In UNIX, the "ls"
       command can be accessed directly as "ls" in C-Kermit.
     * SEND ? prints a list of switches rather than a list of filenames.
       If you want to see a list of filenames, use a (system-dependent)
       construction such as SEND ./? (for UNIX, Windows, or OS/2), SEND
       []? (VMS), etc.
     * In UNIX, OS-9, and Kermit 95, the wildcard characters in previous
       versions were * and ?. In C-Kermit 7.0 they are *, ?, [, ], {, and
       }, with dash used inside []'s to denote ranges and comma used
       inside {} to separate list elements. If you need to include any of
       these characters literally in a filename, precede each one with
       backslash (\).
     * SET QUIET { ON, OFF } is now on the command stack, just like SET
       INPUT CASE, SET COUNT, SET MACRO ERROR, etc, as described on p.458
       of [28]Using C-Kermit, 2nd Edition. This allows any macro or
       command file to SET QUIET ON or OFF without worrying about saving
       and restoring the global QUIET value. For example, this lets you
       write a script that tries SET LINE on lots of devices until it
       finds one free without spewing out loads of error messages, and
       also without disturbing the global QUIET setting, whatever it was.
     * Because of the new "." operator (which introduces assignments),
       macros whose names begin with "." can not be invoked "by name".
       However, they still can be invoked with DO or \fexecute().
     * The syntax of the EVALUATE command has changed. To restore the
       previous syntax, use SET EVALUATE OLD.
     * The \v(directory) variable now includes the trailing directory
       separator; in previous releases it did not. This is to allow
       constructions such as:
  cd \v(dir)data.tmp
       to work across platforms that might have different directory
       notation, such as UNIX, Windows, and VMS.
     * Prior to C-Kermit 7.0, the FLOW-CONTROL setting was global and
       sticky. In C-Kermit 7.0, there is an array of default flow-control
       values for each kind of connection, that are applied automatically
       at SET LINE/PORT/HOST time. Thus a SET FLOW command given before
       SET LINE/PORT/HOST is likely to be undone. Therefore SET FLOW can
       be guaranteed to have the desired effect only if given after the
       SET LINE/PORT/HOST command.
     * Character-set translation works differently in the TRANSMIT
       command when (a) the file character-set is not the same as the
       local end of the terminal character-set, or (b) when the terminal
       character-set is TRANSPARENT.

  1.3. C-Kermit 8.0

   The following incompatible changes were made in C-Kermit 8.0:
     * C-Kermit now accepts doublequotes in most contexts where you
       previously had to use braces to group multiple words into a single
       field, or to force inclusion of leading or trailing blanks. This
       might cause problems in contexts where you wanted the doublequote
       characters to be taken literally. Consult [29]Section 5 of the
       [30]C-Kermit 8.0 Update Notes for further information.
     * Using the SET HOST command to make HTTP connections is no longer
       supported. Instead, use the new [31]HTTP OPEN command.
    ________________________________________________________________________

  2. THE C-KERMIT COMMAND PARSER

   [ [32]Top ] [ [33]Contents ] [ [34]Next ] [ [35]Previous ]

   Various command-related limits are shown in the following table, in
   which the sample values are for a "large memory model" build of
   C-Kermit, typical for modern platforms (Linux, Solaris, AIX, VMS,
   etc). You can see the values for your version of Kermit by giving the
   SHOW FEATURES command. The maximum length for a Kermit command (CMDBL)
   also determines the maximum length for a macro definition, since
   DEFINE is itself a command. The maximum length for a variable name is
   between 256 and 4096 characters, depending on the platform; for array
   declarations and references, that includes the subscript.
       ______________________________________________________________

   Item Symbol Sample
   Value Definition
   Number of characters in a command CMDBL 32763 ckucmd.h
   Number of chars in a field of a command    ATMBL 10238 ckucmd.h
   Nesting level for command files MAXTAKE 54   ckuusr.h
   Nesting level for macros MACLEVEL 128 ckuusr.h
   Nesting level for FOR / WHILE loops FORDEPTH 32 ckuusr.h
   Number of macros MAC_MAX 16384 ckuusr.h
   Size of INPUT buffer INPBUFSIZ 4096 ckuusr.h
   Maximum files to match a wildcard MAXWLD    102400 ckcdeb.h
   Filespecs in MSEND command MSENDMAX 1024 ckuusr.h
   Length for GOTO target label LBLSIZ 50 ckuusr.h
   \fexecute() recursion depth limit CMDDEP 64 ckucmd.h
       ______________________________________________________________

   If you need to define a macro that is longer than CMDBL, you can break
   the macro up into sub-macros or rewrite the macro as a command file.
   In a pinch you can also redefine CMDBL and recompile C-Kermit. All of
   these numbers represent tradeoffs: the bigger the number, the more
   "powerful" Kermit in the corresponding area, but also the bigger the
   program image and possibly disk footprint, and the longer it takes to
   load and initialize.

   In the interactive command parser:

     * EMACS- or VI-style command line editing is not supported.
     * Editing keys are hardwired (Ctrl-U, Ctrl-W, etc).

   If you interrupt C-Kermit before it has issued its first prompt, it
   will exit. This means that you cannot interrupt execution of the
   initialization file, or of an "application file" (file whose name is
   given as the first command-line argument), or of an alternative
   initialization file ("-y filename"), and get to the prompt. There is,
   however, one exception to this rule: you *can* interrupt commands --
   including TAKE commands -- given in the '-C "command list"'
   command-line argument and -- if there were no action commands among
   the command-line arguments -- you will be returned to the C-Kermit
   prompt. So, for example, if you want to start C-Kermit in such a way
   that it executes a command file before issuing its first prompt, and
   you also want to be able to interrupt the command file and get to the
   prompt, include a TAKE command for the desired command in the -C
   argument, for example:

  kermit -C "take dial.scr"

   At the command prompt, if you use the backslash (\) prefix to enter a
   control character, space, or question mark into a command literally,
   the backslash disappears and is replaced by the quoted character. If
   it was a control character, it is shown as a circumflex (^). This
   allows editing (backspace, delete, Ctrl-W) to work correctly even for
   control characters.

   Priot to C-Kermit 8.0, the only way to include a comma literally in a
   macro definition -- as opposed to having it separate commands within
   the definition -- is to enter its ASCII value (44) in backslash
   notation, e.g.:

  DEFINE ROWS RUN MODE CO80\{44}\%1

   In C-Kermit 8.0 you can use constructions like this:

  DEFINE ROWS RUN MODE "CO80,\%1"

   If you quote special characters in a filename (e.g. in the SEND
   command), filename completion may seem to work incorrectly. For
   example, if you have a file whose name is a*b (the name really
   contains an asterisk), and you type "send a\\*<ESC>", the "b" does not
   appear, nor will Ctrl-R redisplay the completed name correctly. But
   internally the file name is recognized anyway.