2 C-Kermit 8.0 General Hints and Tips
5 [1]The Kermit Project, [2]Columbia University
7 As of: C-Kermit 8.0.211, 17 March 2003
8 This page last updated: Sat Apr 10 16:37:37 2004 (New York USA Time)
10 IF YOU ARE READING A PLAIN-TEXT version of this document, it is a
11 plain-text dump of a Web page. You can visit the original (and
12 possibly more up-to-date) Web page here:
14 [3]http://www.columbia.edu/kermit/ckcbwr.html
16 This document contains platform-independent C-Kermit hints and tips.
17 Also see the platform-specific C-Kermit hints and tips document for
18 your platform, for example:
20 [4]http://www.columbia.edu/kermit/ckubwr.html
22 for Unix. This document also applies to [5]Kermit 95 for Windows,
23 which is based on C-Kermit.
25 [ [6]C-Kermit ] [ [7]TUTORIAL ]
26 ________________________________________________________________________
31 1. [9]INCOMPATIBLE CHANGES
32 2. [10]THE C-KERMIT COMMAND PARSER
33 3. [11]MULTIPLE SESSIONS
34 4. [12]NETWORK CONNECTIONS
35 5. [13]MODEMS AND DIALING
36 6. [14]DIALING HINTS AND TIPS
37 7. [15]TERMINAL SERVERS
38 8. [16]TERMINAL EMULATION
41 11. [19]SCRIPT PROGRAMMING
42 ________________________________________________________________________
46 [ [20]Top ] [ [21]Contents ] [ [22]Next ]
48 Source-level patches for C-Kermit 8.0.211:
51 ________________________________________________________________________
53 1. INCOMPATIBLE CHANGES
55 [ [23]Top ] [ [24]Contents ] [ [25]Next ]
57 These are not necessarily exhaustive lists.
61 C-Kermit 6.0 was released 6 September 1996 and is completely
62 documented in [26]Using C-Kermit, 2nd Edition. The following
63 incompatible changes were made in C-Kermit 6.0:
65 * Unless you tell C-Kermit otherwise, if a serial or network
66 connection seems to be open, and you attempt to EXIT or to open a
67 new connection, C-Kermit warns you that an active connection
68 appears to be open and asks you if you really want to close it. If
69 you do not want these warnings, add SET EXIT WARNING OFF to your
70 customization file or script, or give this command at the prompt.
71 * The default for SET { SEND, RECEIVE } PATHNAMES was changed from
72 ON to OFF, to prevent unexpected creation of directories and
73 depositing of incoming files in places you might not know to look.
74 * The default for SET FILE INCOMPLETE was changed from DISCARD to
75 KEEP to allow for file transfer recovery.
76 * The default file-transfer block-check is now 3, rather than 1. If
77 the other Kermit does not support this, the two will drop back to
78 type 1 automatically unless the other Kermit fails to follow the
79 protocol specification.
80 * The default flow-control is now "auto" ("do the right thing for
81 each type of connection"), not Xon/Xoff.
82 * Backslash (\) is no longer a command continuation character. Only
83 - (hyphen, dash) may be used for this in C-Kermit 6.0 and later.
84 * Negative INPUT timeout now results in infinite wait, rather than 1
89 C-Kermit 7.0 was released 1 January 2000. Its new features are
90 documented in the C-Kermit 7.0 Supplement,
91 [27]http://www.columbia.edu/kermit/ckermit2.html. The following
92 incompatible changes were made in C-Kermit 7.0:
93 * The "multiline GET" command is gone. Now use either of the
94 following forms instead:
95 get remote-name local-name
96 get /as-name:local-name remote-name
97 If either name contains spaces, enclose it in braces (or, in
98 C-Kermit 8.0, doublequotes).
99 * To include multiple file specifications in a GET command, you must
100 now use MGET rather than GET:
101 mget file1 file2 file3 ...
102 * C-Kermit 7.0 and later use FAST Kermit protocol settings by
103 default. This includes "unprefixing" of certain control
104 characters. Because of this, file transfers that worked with
105 previous releases might not work in the new release especially
106 against a non-Kermit-Project Kermit protocol implementation (but
107 it is more likely that they will work, and much faster). If a
108 transfer fails, you'll get a context-sensitive hint suggesting
109 possible causes and cures. Usually SET PREFIXING ALL does the
111 * By default C-Kermit 7.0 and later send files in text or binary
112 mode by looking at each file to see which is the appropriate mode.
113 To restore the previous behavior, put SET TRANSFER MODE MANUAL and
114 the desired SET FILE TYPE (TEXT or BINARY) in your C-Kermit
116 * The RESEND and REGET commands automatically switch to binary mode;
117 previously if RESEND or REGET were attempted when FILE TYPE was
118 TEXT, these commands would fail immediately, with a message
119 telling you they work only when the FILE TYPE is BINARY. Now they
120 simply do this for you.
121 * SET PREFIXING CAUTIOUS and MINIMAL now both prefix linefeed (10
122 and 138) in case rlogin, ssh, or cu are "in the middle", since
123 otherwise <LF>~ might appear in Kermit packets, and this would
124 cause rlogin, ssh, or cu to disconnect, suspend,escape back, or
125 otherwise wreck the file transfer. Xon and Xoff are now always
126 prefixed too, even when Xon/Xoff flow control is not in effect,
127 since unprefixing them has proven dangerous on TCP/IP connections.
128 * In UNIX, VMS, Windows, and OS/2, the DIRECTORY command is built
129 into C-Kermit itself rather than implemented by running an
130 external command or program. The built-in command might not behave
131 the way the platform-specific external one did, but many options
132 are available for customization. Of course the underlying
133 platform-specific command can still be accessed with "!", "@", or
134 "RUN" wherever the installation does not forbid. In UNIX, the "ls"
135 command can be accessed directly as "ls" in C-Kermit.
136 * SEND ? prints a list of switches rather than a list of filenames.
137 If you want to see a list of filenames, use a (system-dependent)
138 construction such as SEND ./? (for UNIX, Windows, or OS/2), SEND
140 * In UNIX, OS-9, and Kermit 95, the wildcard characters in previous
141 versions were * and ?. In C-Kermit 7.0 they are *, ?, [, ], {, and
142 }, with dash used inside []'s to denote ranges and comma used
143 inside {} to separate list elements. If you need to include any of
144 these characters literally in a filename, precede each one with
146 * SET QUIET { ON, OFF } is now on the command stack, just like SET
147 INPUT CASE, SET COUNT, SET MACRO ERROR, etc, as described on p.458
148 of [28]Using C-Kermit, 2nd Edition. This allows any macro or
149 command file to SET QUIET ON or OFF without worrying about saving
150 and restoring the global QUIET value. For example, this lets you
151 write a script that tries SET LINE on lots of devices until it
152 finds one free without spewing out loads of error messages, and
153 also without disturbing the global QUIET setting, whatever it was.
154 * Because of the new "." operator (which introduces assignments),
155 macros whose names begin with "." can not be invoked "by name".
156 However, they still can be invoked with DO or \fexecute().
157 * The syntax of the EVALUATE command has changed. To restore the
158 previous syntax, use SET EVALUATE OLD.
159 * The \v(directory) variable now includes the trailing directory
160 separator; in previous releases it did not. This is to allow
161 constructions such as:
163 to work across platforms that might have different directory
164 notation, such as UNIX, Windows, and VMS.
165 * Prior to C-Kermit 7.0, the FLOW-CONTROL setting was global and
166 sticky. In C-Kermit 7.0, there is an array of default flow-control
167 values for each kind of connection, that are applied automatically
168 at SET LINE/PORT/HOST time. Thus a SET FLOW command given before
169 SET LINE/PORT/HOST is likely to be undone. Therefore SET FLOW can
170 be guaranteed to have the desired effect only if given after the
171 SET LINE/PORT/HOST command.
172 * Character-set translation works differently in the TRANSMIT
173 command when (a) the file character-set is not the same as the
174 local end of the terminal character-set, or (b) when the terminal
175 character-set is TRANSPARENT.
179 The following incompatible changes were made in C-Kermit 8.0:
180 * C-Kermit now accepts doublequotes in most contexts where you
181 previously had to use braces to group multiple words into a single
182 field, or to force inclusion of leading or trailing blanks. This
183 might cause problems in contexts where you wanted the doublequote
184 characters to be taken literally. Consult [29]Section 5 of the
185 [30]C-Kermit 8.0 Update Notes for further information.
186 * Using the SET HOST command to make HTTP connections is no longer
187 supported. Instead, use the new [31]HTTP OPEN command.
188 ________________________________________________________________________
190 2. THE C-KERMIT COMMAND PARSER
192 [ [32]Top ] [ [33]Contents ] [ [34]Next ] [ [35]Previous ]
194 Various command-related limits are shown in the following table, in
195 which the sample values are for a "large memory model" build of
196 C-Kermit, typical for modern platforms (Linux, Solaris, AIX, VMS,
197 etc). You can see the values for your version of Kermit by giving the
198 SHOW FEATURES command. The maximum length for a Kermit command (CMDBL)
199 also determines the maximum length for a macro definition, since
200 DEFINE is itself a command. The maximum length for a variable name is
201 between 256 and 4096 characters, depending on the platform; for array
202 declarations and references, that includes the subscript.
203 ______________________________________________________________
207 Number of characters in a command CMDBL 32763 ckucmd.h
208 Number of chars in a field of a command ATMBL 10238 ckucmd.h
209 Nesting level for command files MAXTAKE 54 ckuusr.h
210 Nesting level for macros MACLEVEL 128 ckuusr.h
211 Nesting level for FOR / WHILE loops FORDEPTH 32 ckuusr.h
212 Number of macros MAC_MAX 16384 ckuusr.h
213 Size of INPUT buffer INPBUFSIZ 4096 ckuusr.h
214 Maximum files to match a wildcard MAXWLD 102400 ckcdeb.h
215 Filespecs in MSEND command MSENDMAX 1024 ckuusr.h
216 Length for GOTO target label LBLSIZ 50 ckuusr.h
217 \fexecute() recursion depth limit CMDDEP 64 ckucmd.h
218 ______________________________________________________________
220 If you need to define a macro that is longer than CMDBL, you can break
221 the macro up into sub-macros or rewrite the macro as a command file.
222 In a pinch you can also redefine CMDBL and recompile C-Kermit. All of
223 these numbers represent tradeoffs: the bigger the number, the more
224 "powerful" Kermit in the corresponding area, but also the bigger the
225 program image and possibly disk footprint, and the longer it takes to
228 In the interactive command parser:
230 * EMACS- or VI-style command line editing is not supported.
231 * Editing keys are hardwired (Ctrl-U, Ctrl-W, etc).
233 If you interrupt C-Kermit before it has issued its first prompt, it
234 will exit. This means that you cannot interrupt execution of the
235 initialization file, or of an "application file" (file whose name is
236 given as the first command-line argument), or of an alternative
237 initialization file ("-y filename"), and get to the prompt. There is,
238 however, one exception to this rule: you *can* interrupt commands --
239 including TAKE commands -- given in the '-C "command list"'
240 command-line argument and -- if there were no action commands among
241 the command-line arguments -- you will be returned to the C-Kermit
242 prompt. So, for example, if you want to start C-Kermit in such a way
243 that it executes a command file before issuing its first prompt, and
244 you also want to be able to interrupt the command file and get to the
245 prompt, include a TAKE command for the desired command in the -C
246 argument, for example:
248 kermit -C "take dial.scr"
250 At the command prompt, if you use the backslash (\) prefix to enter a
251 control character, space, or question mark into a command literally,
252 the backslash disappears and is replaced by the quoted character. If
253 it was a control character, it is shown as a circumflex (^). This
254 allows editing (backspace, delete, Ctrl-W) to work correctly even for
257 Priot to C-Kermit 8.0, the only way to include a comma literally in a
258 macro definition -- as opposed to having it separate commands within
259 the definition -- is to enter its ASCII value (44) in backslash
262 DEFINE ROWS RUN MODE CO80\{44}\%1
264 In C-Kermit 8.0 you can use constructions like this:
266 DEFINE ROWS RUN MODE "CO80,\%1"
268 If you quote special characters in a filename (e.g. in the SEND
269 command), filename completion may seem to work incorrectly. For
270 example, if you have a file whose name is a*b (the name really
271 contains an asterisk), and you type "send a\\*<ESC>", the "b" does not
272 appear, nor will Ctrl-R redisplay the completed name correctly. But
273 internally the file name is recognized anyway.
275 Question-mark help does not work during execution of an ASKQ command.
276 The question marks are simply accepted as text.
278 In OUTPUT commands only, \B sends a BREAK signal, \L sends a Long
279 BREAK signal, and \N sends a NUL (ASCII 0). BREAK and Long BREAK are
280 special signals, not characters, and NUL is a character that normally
281 cannot be included in a C string, since it is the C string terminator.
282 If you really want to output a backslash followed by a B, an L, or an
283 N (as is needed to configure certain modems, etc), double the
284 backslash, e.g. "output \\B". In C-Kermit 7.0 or later, you can disarm
285 and re-arm the special OUTPUT-command escapes (\B, \L, and \N) with
286 SET OUTPUT SPECIAL-ESCAPES { OFF, ON }.
288 When using the command-line processor ("kermit -l /dev/tty00 -b
289 19200", etc), note that in some cases the order of the command-line
290 options makes a difference, contrary to the expectation that order of
291 command-line options should not matter. For example, the -b option
292 must be given after the -l option if it is to affect the device
293 specified in the -l option.
294 ________________________________________________________________________
298 [ [36]Top ] [ [37]Contents ] [ [38]Next ] [ [39]Previous ]
300 C-Kermit 7.0 and earlier do not support multiple sessions. When you
301 SET LINE (or SET PORT, same thing) to a new device, or SET HOST to a
302 new host, the previous SET LINE device or network host connection is
303 closed, resulting in hangup of the modem or termination of the network
304 connection. In windowing environments like HP-VUE, NeXTSTEP, Windows,
305 OS/2, etc, you can run separate copies of Kermit in different windows
306 to achieve multiple sessions.
308 To achieve multiple sessions through a single serial port (e.g. when
309 dialing up), you can install SLIP or PPP on your computer and then use
310 C-Kermit's TCP/IP support over the SLIP or PPP connection, assuming
311 you also have TCP/IP networking installed on your computer.
313 C-Kermit 8.0 has the same restriction on SET LINE and SET HOST
314 sessions: only one regular session (dialout, Telnet, etc) can be open
315 at a time. However, version 8.0 adds two new kinds of sessions: FTP
316 and HTTP; one or both of these can be open at the same as a regular
318 ________________________________________________________________________
320 4. NETWORK CONNECTIONS
322 [ [40]Top ] [ [41]Contents ] [ [42]Next ] [ [43]Previous ]
326 The Unix C-Kermit 8.0.206 FTP client had the following bugs at the
327 time most of the 8.0.206 binaries were built for the C-Kermit 8.0
330 1. FTP MGET fails when directory segments contain wildcards, as in
331 "ftp mget */data/*.dat". Work around by doing a separate MGET for
332 each source directory.
333 2. FTP MGET can fail or produce random side effects if you have a
334 TMPDIR or CK_TMP environment variable definition in effect, or a
335 SET TEMP-DIRECTORY value, longer than 7 characters. Work around by
336 giving a SET TEMP-DIRECTORY command with a short value, such as
339 These two bugs are fixed in the source code that is included on the
340 CDROM, and also in Kermit 95 2.1.1. You can tell if a C-Kermit 8.0.206
341 binary has these fixes by typing SHOW VERSION; if it says "FTP Client,
342 8.0.200, 24 Oct 2002" it has the fixes; if the edit number is less
343 that 200, it doesn't, in which case can build a new binary from the
344 source code (or contact us and we'll try to get get one for you).
346 Making TCP/IP Connections Can Take a Long Time
348 The most frequently asked question in many newsgroups is "Why does it
349 take such a long time to make a Telnet connection to (or from) my
350 (e.g.) Linux PC?" (this applies to Kermit as well as to regular Telnet
353 1. Most Telnet servers perform reverse DNS lookups on the client for
354 security and/or logging reasons. If the Telnet client's host
355 cannot be found by the server's local DNS server, the DNS request
356 goes out to the Internet at large, and this can take quite some
357 time. The solution to this problem is to make sure that both
358 client and host are registered in DNS.
359 2. C-Kermit itself performs reverse DNS lookups unless you tell it
360 not to. This is to allow C-Kermit to let you know which host it is
361 actually connected to in case you have made a connection to a
362 "host pool" (multihomed host). You can disable C-Kermit's reverse
363 DNS lookup with SET TCP REVERSE-DNS-LOOKUP OFF.
364 3. C-Kermit 7.0 and later strictly enforce Telnet protocol rules. One
365 such rule is that certain negotiations must be responded to. If
366 C-Kermit sends a such a negotiation and the host does not respond,
367 C-Kermit waits a long time for the reply (in case the network is
368 congested or the host is slow), but eventually will time out. To
369 eliminate the waits (and therefore risk possible protocol
370 mismatches -- or worse -- between Telnet client and server), tell
371 C-Kermit to SET TELNET WAIT OFF (or include the /NOWAIT switch
372 with the TELNET command).
376 In multiuser operating systems such as UNIX and VMS, TCP/IP Rlogin
377 connections are available only to privileged users, since "login" is a
378 privileged socket. Assuming you are allowed to use it in the first
379 place, it is likely to behave differently depending on what type of
380 host you are rlogging in to, due to technical reasons having to do
381 with conflicting interpretations of RFC793 (Out-Of-Band Data) and
382 Rlogin (RFC1122)... "Specifically, the TCP urgent pointer in BSD
383 points to the byte after the urgent data byte, and an RFC-compliant
384 TCP urgent pointer points to the urgent data byte. As a result, if an
385 application sends urgent data from a BSD-compatible implementation to
386 an [44]RFC-1122 compatible implementation then the receiver will read
387 the wrong urgent data byte (it will read the byte located after the
388 correct byte in the data stream as the urgent data byte)." Rlogin
389 requires the use of OOB data while Telnet does not. Therefore, it is
390 possible for Telnet to work between all systems while BSD and System V
391 TCP/IP implementations are almost always a bad mix.
395 On a TCP/IP TELNET connection, you should normally have PARITY set to
396 NONE and (except in VMS C-Kermit) FLOW-CONTROL also set to NONE. If
397 file transfer does not work with these settings (for example, because
398 the remote TELNET server only gives a 7-bit data path), use SET PARITY
399 SPACE. Do not use SET PARITY MARK, EVEN, or ODD on a TELNET connection
400 -- it interferes with TELNET protocol.
402 If echoing does not work right after connecting to a network host or
403 after dialing through a TCP/IP modem server, it probably means that
404 the TELNET server on the far end of the connection is executing the
405 TELNET protocol incorrectly. After initially connecting and
406 discovering incorrect echoing (characters are echoed twice, or not at
407 all), escape back, give the appropriate SET DUPLEX command (FULL or
408 HALF), and then CONNECT again. For a consistently misbehaving
409 connection, you can automate this process in a macro or TAKE file.
411 TELNET sessions are treated just like serial communications sessions
412 as far as "terminal bytesize" and "command bytesize" are concerned. If
413 you need to view and/or enter 8-bit characters during a TELNET
414 session, you must tell C-Kermit to SET TERMINAL BYTESIZE 8, SET
415 COMMAND BYTESIZE 8, and SET PARITY NONE.
417 If you SET TELNET DEBUG ON prior to making a connection, protocol
418 negotiations will be displayed on your screen. You can also capture
419 them in the debug log (along with everything else) and then extract
420 them easily, since all Telnet negotiations lines begin with
421 (uppercase) "TELNET".
422 ________________________________________________________________________
424 5. MODEMS AND DIALING
426 [ [45]Top ] [ [46]Contents ] [ [47]Next ] [ [48]Previous ]
428 External modems are recommended because:
430 * They don't need any special drivers.
431 * They are less likely to interfere with normal operation of your
433 * You can use the lights and speaker to troubleshoot dialing.
434 * You can share them among all types of computers.
435 * You can easily turn them off and on when power-cycling seems
437 * They are more likely to have manuals.
439 Modems can be used by C-Kermit only when they are visible as or
440 through a regular serial port device. Certain modems can not be used
441 in this normal way on many kinds of computers: Winmodems, RPI modems,
442 Controllerless modems, the IBM Mwave, etc; all of these require
443 special drivers that perform some, most, or all of the modem's
444 functions in software. Such drivers are generally NOT available in
445 UNIX or other non-Windows (or non-OS/2, in the case of the Mwave)
448 In order to dial a modem, C-Kermit must know its repertoire of
449 commands and responses. Each modem make and model is likely to have a
450 different repertoire. Since Kermit has no way of knowhing which kind
451 of modem will be dialed, normally you have to tell it with a SET MODEM
454 set modem type usrobotics
459 In the early days, there was a wide variety of modems and command
460 languages. Nowadays, almost every modem uses the Hayes AT command set
461 (but with some differences in the details) and its startup
462 configuration includes error correction, data compression, and
463 hardware (RTS/CTS) flow control. As long as C-Kermit is capable of
464 hardware flow control (as it is on many, but not all, the platforms
465 where it runs, since some operating systems don't support it), the
466 modem can be dailed immediately, without lengthy configuration
467 dialogs, and in fact this is what SET MODEM TYPE GENERIC-HIGH-SPEED
468 does. In C-Kermit 8.0, GENERIC-HIGH-SPEED has become the default modem
469 type, so now it is usually possible to SET LINE, SET SPEED, and DIAL
470 without having to identify your modem. If this doesn't work, of
471 course, then you might have to fall back to the tradiational method:
472 Give a SET MODEM TYPE for a specific modem first, then SET LINE, SET
475 An important change in C-Kermit 6.0 is that when you give a SET MODEM
476 TYPE command to tell Kermit what kind of modem you have, Kermit also
477 sets a number of other modem-related parameters automatically from its
478 internal modem database. Thus, the order in which you give
479 modem-related commands is significant, whereas in prior releases they
480 could be given in any order.
482 In particular, MODEM SPEED-MATCHING is set according to whether the
483 modem is known to be capable of speed buffering. SET MODEM TYPE
484 HAYES-2400 automatically turns SPEED-MATCHING ON, because when the
485 Hayes 2400 reports a particular speed in its CONNECT message, that
486 means its interface speed has changed to that speed, and C-Kermit's
487 must change accordingly if it is to continue communicating. This might
488 cause some confusion if you use "set modem type hayes" for dialing a
489 more advanced type of modem.
491 The new default for flow control is "auto", meaning "do the right
492 thing for each type of connection". So (for example) if your version
493 of C-Kermit supports SET FLOW RTS/CTS and your modem also supports
494 RTS/CTS, then Kermit automatically sets its flow control to RTS/CTS
495 and set modem's flow control to RTS/CTS too before attempting to use
498 For these reasons, don't assume that "set modem type hayes" should be
499 used for all modems that uses the Hayes AT command set. "set modem
500 type hayes" really does mean Hayes 1200 or 2400, which in turn means
501 no hardware flow control, and no speed buffering. This choice will
502 rarely work with a modern high-speed modem.
503 ________________________________________________________________________
505 6. DIALING HINTS AND TIPS
507 [ [49]Top ] [ [50]Contents ] [ [51]Next ] [ [52]Previous ]
509 If you have a high-speed, error-correcting, data-compressing,
510 speed-buffering modem, you should fix the modem's interface speed as
511 high as possible, preferably (at least) four times higher than its
512 maximum connection (modulation) speed to allow compression to work at
513 full advantage. In this type of setup, you must also have an effective
514 means of flow control enabled between C-Kermit and the modem,
515 preferably hardware (RTS/CTS) flow control. On platforms that do not
516 support hardware flow control, it is usually possible to select
517 software flow control (Xon/Xoff), and C-Kermit will do its best to set
518 the modem for local Xon/Xoff flow control too (but then, of course,
519 Ctrl-S and Ctrl-Q characters can not be transmitted on the
522 If you are having trouble dialing your modem, SET DIAL DISPLAY ON to
523 watch the dialing interactions between C-Kermit and your modem.
524 Consult Chapters 3-4 of [53]Using C-Kermit (2nd Ed) for modem-dialing
525 troubleshooting instructions. The following sections offer some
526 addtional hints and tips.
530 If you want to dial a number that starts with #, you'll need to quote
531 the "#" character (as \# or \{35}), since it is also a comment
534 C-Kermit>dial #98765421-1-212-5551212 ; Looks like a comment
535 ?You must specify a number to dial
536 C-Kermit>dial \#98765421-1-212-5551212 ; Works OK
537 C-Kermit>dial =#98765421-1-212-5551212 ; This works too
539 When using a dialing directory, remember what happens if a name is not
542 C-Kermit>dial xyzcorp
543 Lookup: "xyzcorp" - not found - dialing as given
545 This normally does no harm, but some modems might behave strangely
546 when given dial strings that contain certain letters. For example, a
547 certain German modem treats any dial string that contains the letter
548 "s" as a command to fetch a number from its internal list, and replies
549 OK to the ATD command, which is normally not a valid response except
550 for partial dialing. To avoid this situation, use:
555 6.2. The Carrier Signal
557 Remember: In many C-Kermit implementations (depending on the
558 underlying operating system -- mostly Windows, OS/2, and
559 System-V-based UNIX versions, and in C-Kermit 7.0, also VMS), you
560 can't CONNECT to a modem and type the modem's dialing command (like
561 "ATDT7654321") manually, unless you first tell C-Kermit to:
563 SET CARRIER-WATCH OFF
565 This is because (in these implementations), the CONNECT command
566 requires the modem's Carrier Detect (CD) signal to be on, but the CD
567 signal doesn't come on until after dialing is complete. This
568 requirement is what allows C-Kermit to pop back to its prompt
569 automatically when the connection is hung up. See the description of
570 SET CARRIER-WATCH in "Using C-Kermit".
572 Similarly, if your dialed connection drops when CARRIER-WATCH is set
573 to AUTO or ON, you can't CONNECT back to the (now disconnected) screen
574 to see what might have happened unless you first SET CARRIER-WATCH
575 OFF. But sometimes not even SET CARRIER-WATCH OFF will help in this
576 situation: certain platforms (for example Unixware 2.1), once carrier
577 drops, won't let the application do i/o with the device any more. In
578 that case, if you want to use the device again, you have to CLOSE it
579 and OPEN it again. Or you can have Kermit do this for you
580 automatically by telling it to SET CLOSE-ON-DISCONNECT ON.
582 6.3. Dialing and Flow Control
584 Don't SET FLOW RTS/CTS if your modem is turned off, or if it is not
585 presenting the CTS signal. Otherwise, the serial device driver can get
586 stuck waiting for this signal to appear.
588 Most modern modems support RTS/CTS (if they support any hardware flow
589 control at all), but some computers use different RS-232 circuits for
590 the same purposes, e.g. DTR and CD, or DTR and CTS. In such cases, you
591 might be able to make your computer work with your modem by
592 appropriately cross-wiring the circuits in the cable connector, for
593 example the computer's DTR to the modem's RTS, and modem's CD to the
594 computer's CTS. HOWEVER, C-Kermit does not know you have done this. So
595 if you have (say) SET FLOW DTR/CD, C-Kermit will make no attempt to
596 tell the modem to use RTS/CTS. You probably did this yourself when you
597 configured the modem.
599 6.4. The Dial Timeout
601 If it takes your call longer to be completed than the timeout interval
602 that C-Kermit calculates, you can use the SET DIAL TIMEOUT command to
603 override C-Kermit's value. But beware: the modem has its own timeout
604 for completing the call. If it is a Hayes-like modem, C-Kermit adjusts
605 the modem's value too by setting register S7. But the maximum value
606 for S7 might be smaller than the time you need! In that case, C-Kermit
607 sets S7 to 0, 255, or other (modem-specific) value to signify "no
608 timeout". If Kermit attempts to set register S7 to a value higher than
609 your modem's maximum, the modem will say "ERROR" and you will get a
610 "Failure to initialize modem" error. In that case, use SET DIAL
611 TIMEOUT to override C-Kermit's calculation of the timeout value with
612 the highest value that is legal for your modem, e.g. 60.
614 6.5. Escape Sequence Guard Time
616 A "TIES" (Time-Independent Escape Sequence) modem does not require any
617 guard time around its escape sequence. The following text:
621 if sent through a TIES modem, for example because you were uploading
622 this file through it, could pop the modem back into command mode and
623 make it hang up the connection. Later versions of the Telebit T1600
624 and T3000 (version LA3.01E firmware and later), and all WorldBlazers,
627 Although the probability of "+++" appearing in a Kermit packet is
628 markedly lower than with most other protocols (see the [54]File
629 Transfer section below), it can still happen under certain
630 circumstances. It can also happen when using C-Kermit's TRANSMIT
631 command. If you are using a Telebit TIES modem, you can change the
632 modem's escape sequence to an otherwise little-used control character
633 such as Ctrl-_ (Control-Underscore):
637 A sequence of three consecutive Ctrl-_ characters will not appear in a
638 Kermit packet unless you go to extraordinary lengths to defeat more
639 than a few of Kermit's built-in safety mechanisms. And if you do this,
640 then you should also turn off the modem's escape-sequence recognition
645 But when escape sequence recognition is turned off, "modem hangup"
646 (<pause>+++<pause>ATH0<CR>) will not work, so you should also SET
647 MODEM HANGUP RS232-SIGNAL (rather then MODEM-COMMAND).
649 6.6. Adaptive Dialing
651 Some modems have a feature called adaptive dialing. When they are told
652 to dial a number using Tone dialing, they check to make sure that
653 dialtone has gone away after dialing the first digit. If it has not,
654 the modem assumes the phone line does not accept Tone dialing and so
655 switches to Pulse. When dialing out from a PBX, there is almost always
656 a secondary dialtone. Typically you take the phone off-hook, get the
657 PBX dialtone, dial "9" to get an outside line, and then get the phone
658 company's dialtone. In a situation like this, you need to tell the
659 modem to expect the secondary dialtone. On Hayes and compatible
660 modems, this is done by putting a "W" in the dial string at the
661 appropriate place. For example, to dial 9 for an outside line, and
662 then 7654321, use ATDT9W7654321:
664 SET PBX-OUTSIDE-PREFIX 9W
666 (replace "9" with whatever your PBX's outside-line prefix is).
670 Some phone companies are eliminating the busy signal. Instead, they
671 issue a voice message such as "press 1 to automatically redial until
672 the number answers, or...". Obviously this is a disaster for modem
673 calls. If your service has this feature, there's nothing Kermit can do
674 about it. Your modem will respond with NO CARRIER (after a long time)
675 rather than BUSY (immediately), and Kermit will declare the call a
676 failure, rather than trying to redial the same number.
680 There are two ways to hang up a modem: by turning off the serial
681 port's DTR signal (SET MODEM HANGUP-METHOD RS232-SIGNAL) or sending
682 the modem its escape sequence followed by its hangup command (SET
683 MODEM HANGUP-METHOD MODEM-COMMAND). If one doesn't work, try the
684 other. If the automatic hangup performed at the beginning of a DIAL
685 command causes trouble, then SET DIAL HANGUP OFF.
687 The HANGUP command has no effect when C-Kermit is in remote mode. This
688 is on purpose. If C-Kermit could hang up its own controlling terminal,
689 this would (a) most likely leave behind zombie processes, and (b) pose
692 If you DIAL a modem, disconnect, then SET HOST or TELNET, and then
693 HANGUP, Kermit sends the modem's hangup command, such as "+++ATHO".
694 There is no good way to avoid this, because this case can't reliably
695 be distinguished from the case in which the user does SET HOST
696 terminal-server, SET MODEM TYPE name, DIAL. In both cases we have a
697 valid modem type selected and we have a network connection. If you
698 want to DIAL and then later make a regular network connection, you
699 will have to SET MODEM TYPE NONE or SET DIAL HANGUP OFF to avoid this
701 ________________________________________________________________________
705 [ [55]Top ] [ [56]Contents ] [ [57]Next ] [ [58]Previous ]
707 Watch out for terminal server's escape character -- usually a control
708 character such as Ctrl-Circumflex (Ctrl-^). Don't unprefix it in
711 Ciscos -- must often be told to "terminal download"... Cisco ASM
712 models don't have hardware flow control in both directions.
714 Many terminal servers only give you a 7-bit connection, so if you
715 can't make it 8-bit, tell Kermit to "set parity space".
717 The following story, regarding trouble transferring 8-bit files
718 through a reverse terminal server, was contributed by an Annex
719 terminal server user:
721 Using C-Kermit on an HP 9000 712/80 running the HP-UX 10.0
722 operating system. The HP was connected to a Xylogics Annex
723 MICRO-ELS-UX R7.1 8 port terminal server via ethernet. On the
724 second port of the terminal server is an AT&T Paradyne 3810 modem,
725 which is connected to a telephone line. There is a program which
726 runs on the HP to establish a Telnet connection between a serial
727 line on the Annex and a character special file on the HP (/dev
728 file). This is an Annex specific program called rtelnet (reverse
729 telnet) and is provided with the terminal server software. The
730 rtelnet utility runs on top of the pseudo-terminal facility
731 provided by UNIX. It creates host-originiated connections to
732 devices attached ot Annex serial ports. There are several command
733 line arguments to be specified with this program: the IP address of
734 the terminal server, the number of the port to attach to, and the
735 name of the pseudo-device to create. In addition to these there are
736 options to tell rtelnet how to operate on the connect: -b requests
737 negotiation for Telnet binary mode, -d turns on socket-leve
738 debugging, -f enables "connect on the fly" mode, -r removes the
739 device-name if it already exists, etc. The most important of these
740 to be specified when using 8 data bits and no parity, as we found
741 out, was the -t option. This creates a transparent TCP connection
742 to the terminal server. Again, what we assumed to be happening was
743 that the rtelnet program encountered a character sequence special
744 to itself and then "eating" those kermit packets. I think this is
745 all of the information I can give you on the configuration, short
746 of the values associated with the port on the terminal server.
748 How to DIAL from a TCP/IP reverse terminal server (modem server):
750 1. (only if necessary) SET TELNET ECHO REMOTE
751 2. SET HOST terminal-server-ip-name-or-address [ port ]
752 3. SET MODEM TYPE modem-type
753 4. (only if necessary) SET DIAL HANGUP OFF
754 5. (for troubleshooting) SET DIAL DISPLAY ON
757 The order is important: SET HOST before SET MODEM TYPE. Since this is
758 a Telnet connection, serial-port related commands such as SET SPEED,
759 SET STOP-BITS, HANGUP (when MODEM HANGUP-METHOD is RS232), etc, have
760 no effect. However, in C-Kermit 8.0, if the modem server supports
761 [59]RFC-2217 Telnet Com-Port Control protocol, these commands do
762 indeed take effect at the server's serial port.
763 ________________________________________________________________________
765 8. TERMINAL EMULATION
767 [ [60]Top ] [ [61]Contents ] [ [62]Next ] [ [63]Previous ]
769 Except for the Windows, OS/2, and Macintosh versions, C-Kermit does
770 not emulate any kind of terminal. Rather, it acts as a
771 "semitransparent pipe", passing the characters you type during a
772 CONNECT session to the remote host, and sending the characters
773 received from the remote host to your screen. Whatever is controlling
774 your keyboard and screen provides the specific terminal emulation: a
775 real terminal, a PC running a terminal emulator, etc, or (in the case
776 of a self-contained workstation) your console driver, a terminal
779 Kermit is semitrantsparent rather than fully transparent in the
782 * During a TELNET ("set host") session, C-Kermit itself executes the
783 TELNET protocol and performs TELNET negotiations. (But it does not
784 perform TN3270 protocol or any other type of 3270 terminal
786 * If you have changed your keyboard mapping using SET KEY, C-Kermit
787 replaces the characters you type with the characters or strings
789 * If you SET your TERMINAL CHARACTER-SET to anything but
790 TRANSPARENT, C-Kermit translates your keystrokes (after applying
791 any SET KEY definitions) before transmitting them, and translates
792 received characters before showing them on your screen.
793 * If your remote and/or local TERMINAL CHARACTER-SET is an ISO 646
794 7-bit national character set, such as German, French, Italian,
795 Swedish, etc, or Short KOI used for Cyrillic, C-Kermit's CONNECT
796 command automatically skips over ANSI escape sequences to avoid
797 translating their characters. Only ANSI/ISO standard
798 (VT100/200/300-like) 7-bit escape sequence formats are supported
799 for this purpose, no proprietary schemes like H-P, Televideo,
801 * If your version of C-Kermit includes SET TERMINAL APC command,
802 then C-Kermit's CONNECT command will handle APC escape sequences
803 if TERMINAL APC is not set to OFF (which is the default).
805 You can make C-Kermit fully transparent by starting it with the -0
806 (dash zero) command-line option.
808 If you are running C-Kermit under a console driver, or in a terminal
809 window, that emulates the VT100, and use C-Kermit to log in to a VMS
810 system, the console driver or terminal window (not Kermit) is supposed
811 to reply to the "what are you?" query (ESC Z) from the VAX. If it
812 doesn't, and you can't make it do so, then you can (a) live with the
813 "unknown terminal" problem; (b) tell VMS to SET TERMINAL/DEVICE=VT100;
814 (c) program a key using SET KEY to send the appropriate sequence and
815 then punch the key at the right time; or (d) use the VMSLOGIN macro
816 that is defined in CKERMIT.INI to do this for you automatically.
818 SET SESSION-LOG { TEXT, BINARY }, which is effective in UNIX and
819 AOS/VS but not other C-Kermit versions, removes CR, DEL, NUL, XON, and
820 XOFF characters (Using C-Kermit neglects to mention that XON and XOFF
821 are removed). The TEXT-mode setting is ineffective during SCRIPT
822 command execution, as well as on X.25 connections.
823 ________________________________________________________________________
827 [ [64]Top ] [ [65]Contents ] [ [66]Next ] [ [67]Previous ]
829 Except in the terminal-emulating versions, C-Kermit's key mapping
830 facilities are limited to normal "ASCII" keys, and cannot be used with
831 function keys, arrow keys, arcane key combinations, etc. Since
832 C-Kermit runs on such a wide variety of hardware platforms (including,
833 for example, more than 360 different UNIX platforms), it is not
834 possible for C-Kermit to support every conceivable keyboard under
835 every release of every UNIX (or VMS, or ...) product on every
836 different kind of computer possibly under all manner of different
837 console drivers, even if it had the means to do so.
839 In technical terms, C-Kermit uses the read() function to read
840 keystrokes, and read() returns a single byte (value 0 through 255).
841 C-Kermit's SET KEY function applies to these single-byte codes.
842 "Extended function" keys, such as F-keys, arrow keys, etc, usually
843 return either a 2-byte "scan code" or else a character string (such as
844 an escape sequence like "<ESC> O p"). In both cases, C-Kermit has no
845 way to tell the difference between such multibyte key values, and the
846 corresponding series of single-byte key values. This could only be
847 done by accessing the keyboard at a much lower level in a highly
848 platform-dependent manner, probably requiring tens of thousands of
849 lines of code to support even a sampling of the most popular
850 workstation / OS combinations.
852 However, most workstation console drivers (terminal emulation windows,
853 etc) include their own key-mapping facility. For example in AIX, the
854 AIXterm program (in whose window you would run C-Kermit) allows
855 rebinding of the F1-F12 keys to arbitrary strings. The same is true of
856 Xterm and DECterm windows, etc. Consult the technical documentation
857 for your workstation or emulator. See sample Xterm (Xmodmap) mappings
858 in the [68]Unix C-Kermit Hints and Tips document.
860 The SET KEY command (except in Kermit 95) does not allow a key
861 definition to be (or contain) the NUL (\0) character.
862 ________________________________________________________________________
866 [ [69]Top ] [ [70]Contents ] [ [71]Next ] [ [72]Previous ]
868 C-Kermit 7.0 is the first release of C-Kermit to use fast (rather than
869 robust and therefore slow) protocol defaults: long packets, sliding
870 windows, control-character unprefixing, and streaming where possible.
871 This makes most transfers (partner willing) dramatically faster "out
872 of the box" but might break some combinations that worked before. If
873 transfers with C-Kermit 7.0 or later fail where transfers worked with
874 earlier C-Kermit versions, try the following (one at a time, in this
877 1. SET PREFIXING ALL: Disables control-character unprefixing.
878 2. SET STREAMING OFF: Disables streaming.
879 3. CAUTIOUS: Selects medium but cautious protocol settings.
880 4. ROBUST: this command reverts to the most conservative protocol
883 Execution of multiple file transfers by C-Kermit from a command file
884 when in remote mode might exhibit long delays between each transfer.
885 To avoid this, just include the command "SET DELAY 0" in your command
886 file before any of the file-transfer commands.
888 File transfer failures can occur for all sorts of reasons, most of
889 them listed in Chapter 10 of [73]Using C-Kermit. The following
890 sections touch on some that aren't.
892 The [74]C-Kermit 7.0 Release Notes document SEND /COMMAND as taking an
893 argument, but it doesn't. Instead of SEND /COMMAND:{some command},
896 SEND /COMMAND [ other switches such as /AS-NAME: ] command [ arguments... ]
900 Watch out for laptops and their assorted power-saver features; for
901 example, a built-in modem's "auto timeout delay" hanging up the
902 connection in the middle of a file transfer. Most modems, even if they
903 have this feature, do not have it enabled by default. But if you
904 experience otherwise inexplicable disconnections in the midst of your
905 Kermit sessions, check the modem manual for such things as "idle
906 timeout", "auto timeout", etc, and add the command to disable this
907 feature to Kermit's init string for this modem.
911 If uploading a large file to an NFS-mounted disk fails (or is
912 painfully slow), try uploading it to a local disk (e.g. /tmp on Unix)
913 and then copying to the NFS disk later.
917 If you are dialing out and find that downloads work but uploads don't,
918 try again with a lower serial-port speed. Case in point: dialing out
919 on a certain PC from Linux at 115200 bps using a USR Courier 56K
920 "V.Everything" external modem and RTS/CTS flow control. Downloads
921 worked flawlessly, uploads stopped dead after the first few packets
922 were sent. The modem lights showed constant retraining (ARQ light
923 blinks slowly), and the CTS light was off 95% of the time, allowing
924 nothing to get through. Reducing the serial port speed to 57600 bps
925 made the problems go away. Evidently the PC in question has a very
926 fast serial port, since dialing the same modem with a different PC at
927 115200 bps works without incident.
929 10.4. TCP/IP Connections
931 If you have trouble transferring files over a TCP/IP connection, tell
932 Kermit to SET PARITY SPACE and try again. If that doesn't work, also
933 try a shorter packet length or smaller window size (to compensate for
934 certain well-known broken Telnet servers), and/or SET RELIABLE OFF.
936 10.5. Multihop Connections
938 If you have a multihop connection, with the interior nodes in CONNECT
939 mode (Kermit, Telnet, Rlogin, or any other), you can expect (a) file
940 transfer to be slower, and (b) the connection to be less transparent
941 (to control characters, perhaps to the 8th bit) than a more direct
942 connection. C-Kermit 7.0 and later have a "-0" (dash-zero)
943 command-line option to make it 100% transparent in cases where it is
944 to be used in the middle.
948 The recovery feature (RESEND command) that was added in version
949 5A(190) works only for binary-mode transfers. In order for this
950 feature to be useful at all, the default for SET FILE INCOMPLETE was
951 changed from DISCARD to KEEP. Otherwise an interrupted transfer would
952 leave no partial file behind unless you had remembered to change the
953 default. But now you have to pay closer attention to Kermit's messages
954 to know whether a transfer succeeded or failed -- previously, if it
955 failed, the file would not show up on the receiving end at all; in
956 5A(190) and later, you'll get a partial file which could easily be
957 mistaken for the complete file unless you change the default back to
958 DISCARD or read the screen messages, or keep a transaction log.
960 10.7. Filename Collisions
962 SET FILE COLLISION BACKUP is the default. This means:
964 * If you send the same file lots of times, there will be many backup
965 files. There is no automatic mechanism within Kermit to delete
966 them, no notion of a "version retention count", etc, but you can
967 use the PURGE command to clean them up.
968 * If a file arrives that has the same name as a directory, the file
969 transfer fails because Kermit will not rename a directory. Send
970 the file with another name, or use SET FILE COLLISION RENAME.
971 * If the directory lacks write permission, the file transfer fails
972 even if you have write access to the file that is being backed up;
973 in that case, switch to SET FILE COLLISION OVERWRITE or APPEND, or
974 send to a different directory.
976 SET FILE COLLISION UPDATE depends on the date/time stamp in the
977 attribute packet. However, this is recorded in local time, not
978 Universal Time (GMT), and there is no indication of time zone. The
979 time is expressed to the precision of 1 second, but some file systems
980 do not record with this precision -- for example, MS-DOS records the
981 file date/time only to the nearest 2 seconds. This might cause update
982 operations to send more files than necessary.
984 (This paragraph does NOT apply to UNIX, where, as of C-Kermit 7.0,
985 C-Kermit pipes incoming mail and print material directly the mail or
986 print program): When C-Kermit is receiving files from another Kermit
987 program that has been given the MAIL or REMOTE PRINT command, C-Kermit
988 follows the current filename collision action. This can be
989 disconcerting if the action was (for example) BACKUP, because the
990 existing file will be renamed, and the new file will be mailed (or
991 printed) and then deleted. Kermit cannot temporarily change to RENAME
992 because the file collision action occurs when the filename packet is
993 received, and the PRINT or MAIL disposition only comes later, in the
996 Watch out for SET FILE COLLISION RENAME, especially when used in
997 conjunction with recovery. Recall that this option (which is NOT the
998 default) renames the incoming file if a file already exists with the
999 same name (the default is to rename the previously existing file, and
1000 store the incoming file with its own name). It is strongly recommended
1001 that you do not use SET FILE COLLISION RENAME if you ever intend to
1002 use the recovery feature:
1004 * When the file is first received by C-Kermit, its name is changed
1005 if another file already has the same name. When you RESEND the
1006 same file after a failure, C-Kermit will probably try to append
1007 the re-sent portion to the wrong file.
1008 * Assuming that you get RESEND to work with FILE COLLISION RENAME,
1009 C-Kermit, when receiving the remainder of the file during a RESEND
1010 operation, will report back the wrong name. Nothing can be done
1011 about this because the name is reported back before the receiving
1012 Kermit program finds out that it is a recovery operation.
1014 Also watch out for DISABLE DELETE, since this implicitly sets FILE
1015 COLLISION to RENAME. And note tht DELETE is DISABLEd automatically any
1016 time you Kermit is in local mode (i.e. it makes a connection). Also
1017 note that for purposes of DISABLE and ENABLE, "set host *" connections
1018 do not count as local mode even though, strictly speaking, they are.
1022 When referring to foreign MS-DOS, Windows, Atari ST, OS/2, or other
1023 file specifications that contain backslash characters in a C-Kermit
1024 command, you might have to double each backslash, for example:
1026 C-Kermit>get c:\\directory\\foo.txt
1028 This is because backslash is used in C-Kermit commands for introducing
1029 special character codes, variables, functions, etc.
1033 If attempting to cancel local-mode file reception at a very early
1034 stage (i.e. before data packets are exchanged) with X or Z does not
1035 work, use E or Ctrl-C instead, or wait until the first data packets
1038 If you cancel a transfer that is underway using X or Z, and a lot of
1039 window slots are in use, it might take a while for the cancellation to
1040 take effect, especially if you do this on the receiving end; that's
1041 because a lot of packets might already be on their way to you. In that
1042 case, just be patient and let Kermit "drain" them.
1044 If C-Kermit is sending a file, remote-mode packet-mode breakout (three
1045 consecutive Ctrl-C's by default) is not effective until after C-Kermit
1046 sends its first packet. If C-Kermit is receiving a file or is in
1047 server mode, it is effective right away. In the former case, the SET
1048 DELAY value determines the earliest time at which you can break out of
1051 10.10. Partner Peculiarities
1053 When one or both partners is on an SCO operating system such as OSR5,
1054 you might issue the command:
1058 to disable character-set conversion by the terminal driver. Similarly
1063 When using C-Kermit to transfer files with the HP48SX calculator, you
1064 must SET FLOW NONE. The HP48SX does not support flow control, and
1065 evidently also becomes confused if you attempt to use it. You might
1066 also need to use SET SEND PAUSE 100 (or other number). For greater
1067 detail about transferring files the the HP-48, see:
1069 [75]http://www.columbia.edu/kermit/hp48.html
1071 Some communication programs have errors in their implementation of
1072 Kermit attribute packets. If you get an error message from your
1073 communication program like "Attribute error", tell C-Kermit to SET
1074 ATTRIBUTES OFF. Better yet, switch to a real Kermit program.
1076 Some communication software claims to implement Kermit sliding
1077 windows, but does so incorrectly. If sliding window transfers fail,
1078 set C-Kermit's window size to the smallest one that works, for
1079 example, SET WINDOW 1.
1081 For lots more detail about how to cope with defective Kermit partners,
1084 * [76]Coping with Faulty Kermit Implementations (C-Kermit 7.0 and
1086 * [77]Coping with Broken Kermit Partners (C-Kermit 8.0 and later).
1088 The UNIX version of C-Kermit discards carriage returns when receiving
1089 files in text mode. Thus, "bare" carriage returns (sometimes used to
1090 achieve overstriking) are lost.
1091 ________________________________________________________________________
1093 11. SCRIPT PROGRAMMING
1095 [ [78]Top ] [ [79]Contents ] [ [80]Previous ]
1097 11.1. Comments Versus the SCRIPT Command
1099 Remember that ";" and "#" introduce comments when (a) they are the
1100 first character on the line, or (b) they are preceded by at least one
1101 blank or tab within a line. Thus constructions like:
1106 must be coded using backslash notation to keep the data from being
1109 INPUT 5 \59 ; 59 is the decimal ASCII code for ";"
1110 SCRIPT ~0 \35--#--# ; 43 is the decimal ASCII code for "#"
1114 INPUT 5 \; ; Just quote the semicolon
1115 SCRIPT ~0 \#--#--# ; Just quote the "#"
1116 ________________________________________________________________________
1118 11.2. Alphabetic Case and the INPUT Command
1120 INPUT and MINPUT caseless string comparisons do not work for non-ASCII
1121 (international) characters. Workaround: SET INPUT CASE OBSERVE. Even
1122 then, the "lexically less than" and "lexically greater than"
1123 operations (IF LLT, IF LGT) probably won't work as expected. The same
1124 is true for the case-conversion functions \Flower() and \Fupper().
1125 C-Kermit does not know the collating sequence for different character
1126 sets and languages. (On the other hand, it might work depending on
1127 such items as how Kermit was linked, whether your operating supports
1129 ________________________________________________________________________
1131 11.3. NUL (0) Characters in C-Kermit Commands
1133 You can't include a NUL character (\0) in C-Kermit command text
1134 without terminating the character string in which it appears. For
1137 echo In these brackets [\0] is a NUL
1139 will echo "In these brackets [". This applies to ECHO, INPUT, OUTPUT,
1140 and all other commands (but you can represent NUL by "\N" in an OUTPUT
1141 string). This is because C-language strings are terminated internally
1142 by the NUL character, and it allows all of C-Kermit's string
1143 comparison and manipulation functions to work in the normal "C" way.
1161 INPUT operations discard and ignore NUL characters that arrive from
1162 the communication device, meaning that they do not figure into
1163 matching operations (e.g. A<NUL>B matches AB); they are not deposited
1164 in the INPUT buffer (\v(input)); and they are not counted in
1165 \v(incount), with two exceptions:
1167 1. An arriving NUL character restarts the INPUT SILENCE timer.
1168 2. An arriving NUL character terminates the INPUT command with the
1169 SUCCESS condition if the INPUT command was given an empty search
1170 string. In this case \v(incount) is set to 1.
1172 Also, the \v(inchar) variable is null (completely empty) if the last
1173 INPUT character was NUL. That is, there is no way to tell only by
1174 looking at \v(inchar) the difference between a NUL that was INPUT and
1175 no INPUT at all. If the INPUT command succeeded but \v(inchar) is
1176 empty, then a NUL character was input. Also, \v(incount) will be set
1179 Here's a sample script fragment to read characters, possibly including
1180 NUL, from the communication connection and write them to a file:
1183 input 1 ; read one byte
1184 if fail break ; timed out or connection closed
1185 fwrite /char \%c \v(inchar) ; record the byte
1188 This works because when \v(inchar) is NUL, that's equivalent to FWRITE
1189 /CHAR having no text argument at all, in which case it writes a NUL
1192 \v(incount) and \v(inchar) are NOT affected by the CLEAR command.
1193 ________________________________________________________________________
1195 11.4. \ffiles() and \fnextfile() Peculiarities
1197 The following script program:
1199 for \%i 1 \ffiles(oofa.*) 1 {
1203 did not work as expected in C-Kermit 6.0 and earlier but does work in
1204 C-Kermit 7.0 and later.
1205 ________________________________________________________________________
1207 11.5. Commands That Have Only Local Effect
1209 Certain settings are local to each command level, meaning that
1210 subordinate command levels (macros or command files) can change them
1211 without affecting their values at higher command levels. When a new
1212 command level is invoked, the value is inherited from the previous
1213 level. These settings are:
1223 This arrangement allows CASE, TIMEOUT, and ERROR settings, which are
1224 used to control automatic exit from a command file or macro upon
1225 error, to be automatically restored when the command file or macro
1228 The COUNT variable follows this rule too, which permits nested SET
1229 COUNT / IF COUNT loops, as in this example in which the inner loop
1230 counts down from the current COUNT value of the outer loop (try it):
1232 DEFINE INNER WHILE COUNT { WRITE SCREEN { Inner:}, SHOW COUNT }
1234 WHILE COUNT { WRITE SCREEN Outer:, SHOW COUNT, DO INNER }
1236 Keep in mind that an inferior command level cannot manipulate the
1237 COUNT value held by a higher level. For example:
1239 DEFINE OOFA SHOW COUNT, IF COUNT GOTO LOOP
1245 results in an infinite loop; the COUNT value remains at 5 because it
1246 is never decremented at the same level at which it was set.
1247 ________________________________________________________________________
1249 11.6. Literal Braces in Function Calls
1251 Since braces are used in function calls to indicate grouping, there is
1252 no way to pass literal braces to the function itself. Solution: Define
1253 a variable containing the string that has braces. Example:
1256 echo \fsubstring(\%a)
1259 If the string is to start with a leading brace and end with a closing
1260 brace, then double braces must appear around the string (which itself
1261 is enclosed in braces):
1263 define \%a {{{foo}}}
1264 echo \fsubstring(\%a)
1267 This also works for any other kind of string:
1269 define \%a {{ab{cd}}
1270 echo \fsubstring(\%a)
1272 ________________________________________________________________________
1274 11.7. Defining Variables on the C-Kermit Command Line
1276 To define variables on the C-Kermit command line, use the -C
1277 command-line option with one or more DEFINE or ASSIGN commands. Note
1278 that the C-Kermit command line must cope with the quoting rules of
1279 your shell. Examples:
1281 kermit -C "define \\%a foo, define phonenumber 7654321"
1283 In this case we follow UNIX quoting rules by doubling the backslash.
1284 Once C-Kermit starts, the \%a and \m(phonenumber) variables are
1285 defined as indicated and can be used in the normal way.
1287 In DOS or Windows or OS/2 the command would be:
1289 kermit -C "define \%%a foo, define phonenumber 7654321"
1291 Here we need to double the percent sign rather than the backslash
1292 because of DOS shell quoting rules.
1293 ________________________________________________________________________
1295 11.8. Per-Character Echo Check with the OUTPUT Command
1297 Sometimes the OUTPUT command must be used to send commands or data to
1298 a device in "echoplex" mode, meaning that characters must be sent one
1299 at a time, and the next character can not be sent until the echo from
1300 the previous one has been received. For example, a certain PBX might
1301 have this characteristic. Let's say a Kermit script is used to program
1302 the PBX. If characters are sent too fast, they can be lost. It would
1303 seem that the command:
1305 SET OUTPUT PACING milliseconds
1307 could be used to take care of this, but the pacing interval is
1308 constant and must be set large enough to allow even the slowest echo
1309 to finish. If the script is large (an actual example is 14,000 lines
1310 long), this can cause it to take hours longer than it needs to.
1312 Here is a macro you can use to OUTPUT a string in an Echoplex
1318 for \%i 1 \flen(\%*) 1 {
1319 asg \%c \fsubstr(\%*,\%i,1)
1325 C-Kermit 7.0 or later is required.
1327 It sends one character at a time and then waits up to 2 seconds for
1328 the character to be echoed back, but continues to the next character
1329 as soon as the echo appears, so no time is wasted. You can add an IF
1330 FAIL clause after the INPUT in case you want to do something special
1331 about failure to detect an echo within the timeout period. Obviously
1332 you can also change the 2-second limit, and adjust the script in any
1334 ________________________________________________________________________
1336 11.9. Scripted File Transfer
1338 Sometimes a user complains that when she makes a connection by hand,
1339 logs in, and transfers a file, there are no problems, but when she
1340 scripts the the exact same sequence, the file transfer always fails
1341 after a few packets. Here's a scenario where this can happen:
1343 1. Upon logging in to the remote computer, it sends a "What Are You?"
1345 2. When you log in interactively, your terminal emulator sends the
1346 response. This is invisible to you; you don't know it's happening.
1347 3. When you script the login, and begin a file transfer immediately
1348 upon logging in, the host still sends the "What Are You?"
1349 sequence. Kermit's INPUT ECHO setting is ON by default, so the
1350 escape sequence passes through to the terminal, and the terminal
1351 sends its response. But by this time Kermit has already started
1353 4. By default, the local Kermit program examines the keyboard for
1354 interruption characters between every packet. The "What Are You"
1355 response is sitting in the keyboard buffer. Eventually Kermit will
1356 read a character such as "c" that is a valid interruption
1357 character, and the file transfer stops with "User cancelled".
1359 The right way to handle this situation is to have your look for the
1360 "What Are You?" sequence and send the response itself, as described in
1361 Using C-Kermit, pp.429-431. Or you can work around it by telling the
1362 local Kermit to "set input echo off" and/or "set transfer interruption
1364 ________________________________________________________________________
1368 Escape sequences (or any strings that contain control characters)
1369 can't be used as labels, GOTO targets, or SWITCH cases.
1371 [ [81]Top ] [ [82]Contents ] [ [83]C-Kermit Home ] [ [84]C-Kermit 8.0
1372 Overview ] [ [85]Kermit Home ]
1373 _________________________________________________________________
1375 C-Kermit 8.0 Unix Hints and Tips / [86]The Kermit Project /
1376 [87]Columbia University / [88]kermit@columbia.edu / 10 April 2004
1380 1. http://www.columbia.edu/kermit/
1381 2. http://www.columbia.edu/
1382 3. http://www.columbia.edu/kermit/ckcbwr.html
1383 4. http://www.columbia.edu/kermit/ckubwr.html
1384 5. http://www.columbia.edu/kermit/k95.html
1385 6. http://www.columbia.edu/kermit/ckermit.html
1386 7. http://www.columbia.edu/kermit/ckututor.html
1387 8. http://www.columbia.edu/kermit/ckcbwr.html#x0
1388 9. http://www.columbia.edu/kermit/ckcbwr.html#x1
1389 10. http://www.columbia.edu/kermit/ckcbwr.html#x2
1390 11. http://www.columbia.edu/kermit/ckcbwr.html#x3
1391 12. http://www.columbia.edu/kermit/ckcbwr.html#x4
1392 13. http://www.columbia.edu/kermit/ckcbwr.html#x5
1393 14. http://www.columbia.edu/kermit/ckcbwr.html#x6
1394 15. http://www.columbia.edu/kermit/ckcbwr.html#x7
1395 16. http://www.columbia.edu/kermit/ckcbwr.html#x8
1396 17. http://www.columbia.edu/kermit/ckcbwr.html#x9
1397 18. http://www.columbia.edu/kermit/ckcbwr.html#x10
1398 19. http://www.columbia.edu/kermit/ckcbwr.html#x11
1399 20. http://www.columbia.edu/kermit/ckcbwr.html#top
1400 21. http://www.columbia.edu/kermit/ckcbwr.html#contents
1401 22. http://www.columbia.edu/kermit/ckcbwr.html#x2
1402 23. http://www.columbia.edu/kermit/ckcbwr.html#top
1403 24. http://www.columbia.edu/kermit/ckcbwr.html#contents
1404 25. http://www.columbia.edu/kermit/ckcbwr.html#x2
1405 26. http://www.columbia.edu/kermit/ck60manual.html
1406 27. http://www.columbia.edu/kermit/ckermit2.html
1407 28. http://www.columbia.edu/kermit/ck60manual.html
1408 29. http://www.columbia.edu/kermit/ckermit80.html#x5
1409 30. http://www.columbia.edu/kermit/ckermit80.html
1410 31. http://www.columbia.edu/kermit/ckermit80.html#x2.2
1411 32. http://www.columbia.edu/kermit/ckcbwr.html#top
1412 33. http://www.columbia.edu/kermit/ckcbwr.html#contents
1413 34. http://www.columbia.edu/kermit/ckcbwr.html#x3
1414 35. http://www.columbia.edu/kermit/ckcbwr.html#x1
1415 36. http://www.columbia.edu/kermit/ckcbwr.html#top
1416 37. http://www.columbia.edu/kermit/ckcbwr.html#contents
1417 38. http://www.columbia.edu/kermit/ckcbwr.html#x4
1418 39. http://www.columbia.edu/kermit/ckcbwr.html#x2
1419 40. http://www.columbia.edu/kermit/ckcbwr.html#top
1420 41. http://www.columbia.edu/kermit/ckcbwr.html#contents
1421 42. http://www.columbia.edu/kermit/ckcbwr.html#x5
1422 43. http://www.columbia.edu/kermit/ckcbwr.html#x3
1423 44. ftp://ftp.isi.edu/in-notes/rfc1122.txt
1424 45. http://www.columbia.edu/kermit/ckcbwr.html#top
1425 46. http://www.columbia.edu/kermit/ckcbwr.html#contents
1426 47. http://www.columbia.edu/kermit/ckcbwr.html#x6
1427 48. http://www.columbia.edu/kermit/ckcbwr.html#x4
1428 49. http://www.columbia.edu/kermit/ckcbwr.html#top
1429 50. http://www.columbia.edu/kermit/ckcbwr.html#contents
1430 51. http://www.columbia.edu/kermit/ckcbwr.html#x7
1431 52. http://www.columbia.edu/kermit/ckcbwr.html#x5
1432 53. http://www.columbia.edu/kermit/ck60manual.html
1433 54. http://www.columbia.edu/kermit/ckcbwr.html#x10
1434 55. http://www.columbia.edu/kermit/ckcbwr.html#top
1435 56. http://www.columbia.edu/kermit/ckcbwr.html#contents
1436 57. http://www.columbia.edu/kermit/ckcbwr.html#x8
1437 58. http://www.columbia.edu/kermit/ckcbwr.html#x6
1438 59. ftp://ftp.isi.edu/in-notes/rfc2217.txt
1439 60. http://www.columbia.edu/kermit/ckcbwr.html#top
1440 61. http://www.columbia.edu/kermit/ckcbwr.html#contents
1441 62. http://www.columbia.edu/kermit/ckcbwr.html#x9
1442 63. http://www.columbia.edu/kermit/ckcbwr.html#x7
1443 64. http://www.columbia.edu/kermit/ckcbwr.html#top
1444 65. http://www.columbia.edu/kermit/ckcbwr.html#contents
1445 66. http://www.columbia.edu/kermit/ckcbwr.html#x10
1446 67. http://www.columbia.edu/kermit/ckcbwr.html#x8
1447 68. http://www.columbia.edu/kermit/ckubwr.html
1448 69. http://www.columbia.edu/kermit/ckcbwr.html#top
1449 70. http://www.columbia.edu/kermit/ckcbwr.html#contents
1450 71. http://www.columbia.edu/kermit/ckcbwr.html#x11
1451 72. http://www.columbia.edu/kermit/ckcbwr.html#x9
1452 73. http://www.columbia.edu/kermit/ck60manual.html
1453 74. http://www.columbia.edu/kermit/ckermi70.htm
1454 75. http://www.columbia.edu/kermit/hp48.html
1455 76. http://www.columbia.edu/kermit/ckermit70.html#x4.22
1456 77. http://www.columbia.edu/kermit/ckermit80.html#x15
1457 78. http://www.columbia.edu/kermit/ckcbwr.html#top
1458 79. http://www.columbia.edu/kermit/ckcbwr.html#contents
1459 80. http://www.columbia.edu/kermit/ckcbwr.html#x10
1460 81. http://www.columbia.edu/kermit/ckcbwr.html#top
1461 82. http://www.columbia.edu/kermit/ckcbwr.html#contents
1462 83. http://www.columbia.edu/kermit/ckermit.html
1463 84. http://www.columbia.edu/kermit/ck80.html
1464 85. http://www.columbia.edu/kermit/index.html
1465 86. http://www.columbia.edu/kermit/index.html
1466 87. http://www.columbia.edu/
1467 88. mailto:kermit@columbia.edu