C-Kermit Help Reference

Mon, 01 Jan 0001 00:00:00 +0000

C-Kermit Help Reference

Generated from a running kermit build by tools/gen_help_reference.py. Do not edit by hand.

Introductory Material

INTRO

Welcome to UNIX C-Kermit communications software for:
 . Error-free and efficient file transfer
 . Terminal connection
 . Script programming
 . International character set conversion
 . Numeric and alphanumeric paging
 
Supporting:
 . Serial connections, direct or dialed.
 . Automatic modem dialing
 . TCP/IP network connections:
   - Telnet sessions
   - SSH connections via external agent
   - Rlogin sessions
   - FTP sessions
   - HTTP 1.1 sessions
   - Internet Kermit Service
 
While typing commands, you may use the following special characters:
 . DEL, RUBOUT, BACKSPACE, CTRL-H: Delete the most recent character typed.
 . CTRL-W:      Delete the most recent word typed.
 . CTRL-U:      Delete the current line.
 . CTRL-R:      Redisplay the current line.
 . CTRL-P:      Command recall - go backwards in command recall buffer.
 . CTRL-B:      Command recall - same as Ctrl-P.
 . CTRL-N:      Command recall - go forward in command recall buffer.
 . CTRL-K:      Insert the most recently entered local file specifiction.
 . ?            (question mark) Display a menu for the current command field.
 . ESC          (or TAB or Ctrl-I) Attempt to complete the current field.
 . \            (backslash) include the following character literally
                or introduce a backslash code, variable, or function.
 
IMPORTANT: Since backslash (\) is Kermit's command-line escape character,
you must enter DOS, Windows, or OS/2 pathnames using either forward slash (/)
or double backslash (\\) as the directory separator in most contexts.
Examples: C:/TMP/README.TXT, C:\\TMP\\README.TXT.
 
Command words other than filenames can be abbreviated in most contexts.
 
Basic commands:
  EXIT          Exit from Kermit
  HELP          Request general help
  HELP command  Request help about the given command
  TAKE          Execute commands from a file
  TYPE          Display a file on your screen
  ORIENTATION   Explains directory structure
 
Commands for file transfer:
  SEND          Send files
  RECEIVE       Receive files
  GET           Get files from a Kermit server
  RESEND        Recover an interrupted send
  REGET         Recover an interrupted get from a server
  SERVER        Be a Kermit server
 
File-transfer speed selection:
  FAST          Use fast settings -- THIS IS THE DEFAULT
  CAUTIOUS      Use slower, more cautious settings
  ROBUST        Use extremely slow and cautious settings
 
File-transfer performance fine tuning:
  SET RECEIVE PACKET-LENGTH  Kermit packet size
  SET WINDOW                 Number of sliding window slots
  SET PREFIXING              Amount of control-character prefixing
 
To make a direct serial connection:
  SET LINE      Select serial communication device
  SET SPEED     Select communication speed
  SET PARITY    Communications parity (if necessary)
  SET FLOW      Communications flow control, such as RTS/CTS
  CONNECT       Begin terminal connection
 
To dial out with a modem:
  SET DIAL DIRECTORY     Specify dialing directory file (optional)
  SET DIAL COUNTRY-CODE  Country you are dialing from (*)
  SET DIAL AREA-CODE     Area-code you are dialing from (*)
  LOOKUP                 Lookup entries in your dialing directory (*)
  SET MODEM TYPE         Select modem type
  SET LINE               Select serial communication device
  SET SPEED              Select communication speed
  SET PARITY             Communications parity (if necessary)
  DIAL                   Dial the phone number
  CONNECT                Begin terminal connection
 
Further info:   HELP DIAL, HELP SET MODEM, HELP SET LINE, HELP SET DIAL
(*) (For use with optional dialing directory)
 
To make a network connection:
  SET NETWORK DIRECTORY  Specify a network services directory (optional)
  LOOKUP                 Lookup entries in your network directory
  SET NETWORK TYPE       Select network type (if more than one available)
  SET HOST               Make a network connection but stay in command mode
  CONNECT                Begin terminal connection
  TELNET                 Select a Telnet host and CONNECT to it
  RLOGIN                 Select an Rlogin host and CONNECT to it
  SSH [ OPEN ]           Select an SSH host and CONNECT to it
  FTP [ OPEN ]           Make an FTP connection
  HTTP OPEN              Make an HTTP connection
 
To return from a terminal connection to the C-Kermit prompt:
  Type your escape character followed by the letter C.
 
To display your escape character:
  SHOW ESCAPE
 
To display other settings:
  SHOW COMMUNICATIONS, SHOW TERMINAL, SHOW FILE, SHOW PROTOCOL, etc.
 
The manual for C-Kermit is the book "Using C-Kermit".  For information
about the manual, visit:
  http://www.kermitproject.org/usingckermit.html
 
For an online C-Kermit tutorial, visit:
  http://www.kermitproject.org/ckututor.html
 
To learn about script programming and automation:
  http://www.kermitproject.org/ckscripts.html
 
For further information about a particular command, type HELP xxx,
where xxx is the name of the command.  For documentation, news of new
releases, and information about other Kermit software, visit the
Kermit Project website:
 
  http://www.kermitproject.org/
 
For information about technical support please visit this page:
 
  http://www.kermitproject.org/support.html

NEWS

Welcome to C-Kermit 11.
For changes to C-Kermit since version 9.0 of 2011, please visit
https://github.com/OpenKermit/ckermit/blob/main/doc/changelog.md 
Documentation:
 . https://www.kermitproject.org/ckbindex.html
    Online index to C-Kermit documentation.
 . https://www.kermitproject.org/ckututor.html
    C-Kermit tutorial.
 
If the release date shown by the VERSION command is long past, be sure to
check the Kermit website to see if there have been updates:
 
  https://www.openkermit.org/    (Open Kermit home page)
  https://github.com/openkermit/ckermit/ (C-Kermit project page)

LICENSE

Copyright (C) 1985, 2025,
  The Trustees of Columbia University in the City of New York.
Copyright (C) 2025-2026, John Goerzen.
All rights reserved.
 
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
 
 + Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
 
 + Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in
   the documentation and/or other materials provided with the
   distribution.
 
 + Neither the name of Columbia University nor the names of its
   contributors may be used to endorse or promote products derived
   from this software without specific prior written permission.
 
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
Portions Copyright (C) 1990, Massachusetts Institute of Technology.
Portions Copyright (C) 1991, 1993 Regents of the University of California.
Portions Copyright (C) 1991, 1992, 1993, 1994, 1995 by AT&T.
Portions Copyright (C) 1995, 1997, Eric Young <eay@cryptosoft.com>.
 
For further information, visit the Open Kermit website:
https://www.openkermit.org/ .

SUPPORT

Live technical support for Kermit software is no longer available
from Columbia University, as it was from mid-1981 until mid-2011 when
the Kermit Project was cancelled.  Beginning with version 9.0, C-Kermit
is Open Source software.  The Kermit project has been moved to:
 
  http://www.kermitproject.org/
 
The C-Kermit home page is here:
 
  http://www.kermitproject.org/ckermit.html
 
The documentation for C-Kermit is listed here:
 
  http://www.kermitproject.org/ckermit.html#doc
 
A C-Kermit tutorial is here:
 
  http://www.kermitproject.org/ckututor.html
 
The C-Kermit Frequently Asked Questions page is here:
 
  http://www.kermitproject.org/ckfaq.html
 
and the Kermit Project Technical Support page is here:
 
  http://www.kermitproject.org/support.html
  
If you have a problem or question that is not addressed on the website
you can send email to:
 
  support@kermitproject.org
 
and as long as anyone is still at that address, it will be answered
on a best-effort basis.

Commands

_ASG

Synonym: _ASSIGN

C-Kermit on high latency links

Mon, 01 Jan 0001 00:00:00 +0000

C-Kermit on high latency links

Here I discuss using C-Kermit for links with very high latencies (measured in minutes, hours, or even days). This can include radio networks such as Meshtastic, satellite links, email as a carrier, etc.

Default C-Kermit is inappropriate for these settings because timeouts will cause excessive retransmits within a few seconds. However, C-Kermit is quite flexible and can easily be configured for success in these situations.

The default timeout and retry values are far too aggressive for RTTs (round trip times) of this scale. They’ll abort a transfer before an ACK (packet acknowledgment) could arrive. Tuning prevents that problem.

How this site is built

Mon, 01 Jan 0001 00:00:00 +0000

This site is built for modern clients using Small Technology. It is served from static files, which are themselves small. It should make no references to any resources from other servers, which helps protect the Privacy of visitors.

It is available on both the small web and Gemini.

Each page on this site starts as an org-roam note. org-roam helps highlight, make, and maintain links between related concepts, and you will no doubt notice many, many links here. Since org-roam is a layer atop org-mode, the pages are, of course, in org-mode format.

IPv6 in C-Kermit

Mon, 01 Jan 0001 00:00:00 +0000

IPv6 in C-Kermit

C-Kermit introduced IPv6 support in version 11.0.

This support includes full IPv6 support for Kermit’s own sockets (raw, telnet, and SSL/TLS) as well as the FTP and HTTP clients. The FTP client adds support for EPRT and EPSV as necessary for IPv6.

Notes on usage

SET TCP ADDRESS-FAMILY lets you configure whether to use IPv4, IPv6, or both (the default).

When giving a string that contains an IP address and a port number separated by colons, an IPv6 address (which itself contains colons) must be enclosed in [ and ] brackets. This mimics behavior in other situations (such as URLs) where similar situations are encountered. When a port number is not expected, neither are brackets.

OpenKermit C-Kermit Changelog

Mon, 01 Jan 0001 00:00:00 +0000

OpenKermit C-Kermit Changelog

FIXME: move IPv6 notes to separate file

C-Kermit 11.0.0

Dedication

I dedicate this release of C-Kermit to Frank da Cruz.

Frank was directly involved with Kermit for 44 years, from its initial design in 1981 all the way through 2025. He maintained Kermit as an Open Source project after Columbia University ended its sponsorship. I know of no other Open Source project where the founder remains so personally involved for so long.

Search Results

Mon, 01 Jan 0001 00:00:00 +0000

Using C-Kermit to connect to a DOS BBS

Mon, 01 Jan 0001 00:00:00 +0000

Using C-Kermit to connect to a DOS BBS

Background

DOS BBSs typically use the DOS CP437 character set, while modern terminals use UTF-8. The line-drawing characters often used on a DOS BBS won’t show up properly on a terminal expecting UTF-8.

C-Kermit can translate live. It also supports the XModem, YModem, and ZModem protocols often used for file transfer by BBSs (you may need to install a package called lrzsz or rzsz to enable this.)

Index on Open Kermit Project

C-Kermit Help Reference

C-Kermit Help Reference

Introductory Material

INTRO

NEWS

LICENSE

SUPPORT

Commands

_ASG

C-Kermit on high latency links

C-Kermit on high latency links

How this site is built

IPv6 in C-Kermit

IPv6 in C-Kermit

Notes on usage

OpenKermit C-Kermit Changelog

OpenKermit C-Kermit Changelog

C-Kermit 11.0.0

Dedication

Search Results

Using C-Kermit to connect to a DOS BBS

Using C-Kermit to connect to a DOS BBS

Background