Manpages

NAME

kermit - C-Kermit 10.0: transport- and platform-independent interactive and scriptable communications software.

This document is intended to give the beginner sufficient information to make basic use of C-Kermit 10.0. Although it might be rather long for a Unix manual page, it’s still far shorter than the C-Kermit manual, which should be consulted for advanced topics such as customization, character-sets, scripting, etc. We also attempt to provide a clear structural overview of C-Kermit’s many capabilities, functional areas, states, and modes and their interrelation, that should be helpful to beginners and veterans alike, as well as to those upgrading to version 10.0 from earlier releases.

This document is also available as a Web page at:

https://kermitproject.org/ckututor.html

DESCRIPTION

C-Kermit is an all-purpose communications software package originally from the Kermit Project at Columbia University and now from the independent Open Source Kermit Project that:

C-Kermit is a modem program, a Telnet client, an SSH client, an FTP client, an HTTP client, and on selected platforms, also an X.25 client. It can make its own secure Internet connections using IETF-approved security methods including Kerberos IV, Kerberos V, SSL/TLS, and SRP and it can also make SSH connections through your external SSH client application. It can be the far-end file-transfer or client/server partner of your desktop Kermit client. It can also accept incoming dialed and network connections. It can even be installed as an Internet service on its own standard TCP socket, 1649 [RFC2839, RFC2840].

And perhaps most important, everything you can do "by hand" (interactively) with C-Kermit, can be "scripted" (automated) using its built-in cross-platform transport-independent script programming language, which happens to be identical to its interactive command language.

This manual page offers an overview of C-Kermit 10.0 for Unix ("Unix" is an operating system family that includes AIX, DG/UX, FreeBSD, HP-UX, IRIX, Linux, Mac OS X, NetBSD, OpenBSD, Open Server, Open Unix, QNX, Solaris, SunOS, System V R3, System V R4, Tru64 Unix, Unixware, Xenix, and many others). For thorough coverage, please consult the published C-Kermit manual and supplements (see DOCUMENTATION below). For further information about C-Kermit, Kermit software for other platforms, and Kermit manuals, visit the Kermit Project website:

https://kermitproject.org/

This is a longer-than-average manual page, and yet it barely scratches the surface. Don’t be daunted. C-Kermit is a large and complex package, evolving over decades of practice and experience, but that doesn’t mean it’s hard to learn or use. Its most commonly used functions are explained here with pointers to additional information elsewhere.

SYNOPSIS

kermit [ filename ] [ options ] [ {=,--,+} text ] ]

or:

kermit URL

If the first command-line argument is the name of a file, interactive-mode commands are executed from the file. The ’=’ (or "--") argument tells Kermit not to parse the remainder of the command line, but to make the words following ’=’ available as \%1, \%2, ... \%9. The "+" argument is like "=" but for use in "kerbang scripts" (explained below). A second command-line format allows the one and only argument to be a Telnet, FTP, HTTP, or IKSD URL.

Order of execution:

Some command-line options can cause actions (such as -s to send a file); others just set parameters. If any action options are included on the command line, Kermit exits when finished unless also given the -S ("stay") option. If no action options are given, no initialization or command files contained an EXIT or QUIT command, and no fatal errors occurred, Kermit issues its prompt and waits for you to type commands.

Bear in mind that C-Kermit can be built with selected features disabled, and also that certain features are not available on all platforms. For example, C-Kermit can’t be built with TCP/IP support on a platform that does not have TCP/IP header files and libraries (and even if Kermit does include TCP/IP support, it can’t be used to make TCP/IP connections on a computer that does not have a TCP/IP stack installed). If your version of C-Kermit lacks a feature mentioned here, use its SHOW FEATURES command to see what might have been excluded.

C-Kermit has three kinds of commands: regular single-letter command-line options, extended-format command-line options, and interactive commands.

Like most Unix commands, C-Kermit can be given options on the command line. But C-Kermit also can be used interactively by giving it commands composed of words, which are more intuitive than cryptic command-line options, and more flexible too. In other words, you don’t have to use C-Kermit’s command-line options, but they are available if you want to. (By the same token, you don’t have to use its interactive commands either -- you can use either or both in any combination.)

C-Kermit is generally installed in the PATH as "kermit", and therefore is invoked by typing the word "kermit" (lowercase) at the shell prompt, and then pressing the Return or Enter key. If you wish to include command-line options, put them after the word "kermit" but before pressing Return or Enter, separated by spaces, for example:

$ kermit -s ckermit.tar.gz

(’$’ is the shell prompt; "kermit -s ckermit.tar.gz" is what you type, followed by Return or Enter.)

OPTIONS

Here is a list of C-Kermit’s single-letter command-line options, which start with a single dash (-), in ASCII ("alphabetical") order. Alphabetic case is significant (-A is not the same as -a). Action options are tagged "ACTION".

Extended command-line options (necessary because single-letter ones are about used up) start with two dashes (--), with words rather than single letters as option names. If an extended option takes an argument, it is separated from the option word by a colon (:). Extended options include:
--bannerfile:filename

File to display upon startup or IKSD login.

--cdfile:filename

File to be sent for display to the client when server changes directory (filename is relative to the changed-to directory).

--cdmessage:{on,off}

Enable/disable the server CD message feature.

--help

Prints usage message for extended options.

--helpfile:filename

Designates a file containing custom text to replace the top-level HELP command.

--nointerrupts

Disables keyboard interrupts.

--noperms

Disables the Kermit protocol file Permissions attribute, to prevent transmission of file permissions (protection) from sender to receiver.

--version

(ACTION) C-Kermit prints its version number.

Plus several other IKSD-Only options described at:

https://kermitproject.org/iksd.html

See the file-transfer section for examples of command-line invocation.

COMMAND LANGUAGE

C-Kermit’s interactive command language is the subject of a 622-page book and another several hundred pages of updates, far too much for a manual page. But it’s not hard to get started. At the shell prompt, just type "kermit" to get C-Kermit’s interactive command prompt:

$ kermit
(/current/directory) C-Kermit>

Begin by typing "help" (and then press the Return or Enter key) for a top-level overview, read it, and go from there. Your second command should probably be "intro" (introduction). Note the prompt shows your current directory (unless you tell Kermit to prompt you with something else).

Interactive commands are composed mainly of regular English words, usually in the form of imperative sentences, such as:

send somefile.txt

which tells Kermit to send (transfer) the file whose name is somefile.txt, or:

set transfer mode automatic

which sets Kermit’s "transfer mode" to "automatic" (whatever that means).

While typing commands, you can abbreviate, ask for help (by pressing the "?" key anywhere in a command), complete keywords or filenames (with the Tab or Esc key), and edit your typing with Backspace or Delete, Ctrl-W, Ctrl-U, etc. You can also recall previous commands, save your command history, and who knows what else. Give the INTRO command for details.

C-Kermit has hundreds of commands, and they can be issued in infinite variety and combinations, including commands for:

And of course QUIT or EXIT to get out and HELP to get help, and for programmers: loops, decision making, variables, arrays, associative arrays, integer and floating point arithmetic, macros, built-in and user-defined functions, string manipulation, pattern matching, block structure, scoping, recursion, and even a built-in LISP regular expression interpreter. To get a list of all C-Kermit’s commands, type a question mark (?) at the prompt. To get a description of any command, type HELP followed by the name of the command, for example:

help send

The command interruption character is Ctrl-C (hold down the Ctrl key and press the C key).

The command language "escape character", used to introduce variable names, function invocations, and so on, is backslash (\). If you need to include a literal backslash in a command, type two of them, e.g.:

get c:\\k95\\k95custom.ini

Command Files, Macros, and Scripts
A file containing Kermit commands is called a Kermit command file or Kermit script. It can be executed with Kermit’s TAKE command:

(/current/dir) C-Kermit> take commandfile

(where "commandfile" is the name of the command file).

In Unix only, a Kermit command file can also be executed directly by including a "kerbang" line as the first line of the file:

#!/usr/local/bin/kermit +

That is, a top line that starts with "#!", followed immediately by the full path of the Kermit executable, and then, if the Kermit script is to be given arguments on the command line, a space and a plus sign. The script file must also have execute permission:

chmod +x commandfile

Except for the " +" part, this is exactly the same as you would do for a shell script, a Perl script, etc. Here’s a simple but useless example script that regurgitates its arguments (up to three of them):

#!/usr/local/bin/kermit +
if defined \%1 echo "Argument 1: \%1"
if defined \%2 echo "Argument 2: \%2"
if defined \%3 echo "Argument 3: \%3"
if defined \%4 echo "etc..."
exit

If this file is stored in your current directory as "commandfile", then:

./commandfile one two three four five

prints:

Argument 1: one
Argument 2: two
Argument 3: three
etc...

This illustrates the basic structure of a standalone Kermit script: the "kerbang line", then some commands. It should end with "exit" unless you want the Kermit prompt to appear when it is finished. \%1 is the first argument, \%2 the second, and so on.

You can also create your own commands by defining named macros composed of other Kermit commands (or macros). For example:

define mydelete {
local trash
assign trash \v(home)trashcan/
if not defined \%1 end 1 "Delete what?"
if wild \%1 {
end 1 "Deleting multiple files is too scary"
}
if not exist \%1 end 1 "I can’t find \%1"
if not directory \m(trash) {
mkdir \m(trash)
if fail end 1 "No trash can"
}
rename /list \%1 \m(trash)
}
define myundelete {
local trash
assign trash \v(home)trashcan/
if not defined \%1 end 1 "Undelete what?"
if wild \%1 {
end 1 "Undeleting multiple files is too hard"
}
if not directory \m(trash) end 1 "No trash can"
if not exist \m(trash)\%1 {
end 1 "I can’t find \%1 in trash can"
}
rename /list \m(trash)\%1 .
}

These sample macros are not exactly production quality (they don’t handle filenames that include path segments, they don’t handle multiple files, etc), but you get the idea: you can pass arguments to macros, and they can check them and make other kinds of decisions. If you put the above lines into your initialization or customization file (explained below), you’ll have MYDELETE and MYUNDELETE commands available every time you start Kermit, at least as long as you don’t suppress execution of the initialization file. (Exercise for the reader: Make these macros generally useful: remove limitations, add trashcan display, browsing, emptying, etc.)

Kerbang scripts execute without the initialization file. This to keep them portable and also to make them start faster. If you want to write Kerbang scripts that depend on the initialization file, include the command

take \v(home).kermrc

at the desired spot in the script. By the way, \v(xxx) is a built-in variable (xxx is the variable name, "home" in this case). To see what built-in variables are available, type "show variables" at the C-Kermit prompt. To see what else you can show, type "show ?". \m(xxx) is a user defined variable (strictly speaking, it is a macro used as a variable).

Command List
C-Kermit has more than 200 top-level commands, and some of these, such as SET, branch off into hundreds of subcommands of their own, so it’s not practical to describe them all here. Instead, here’s a concise list of the most commonly used top-level commands, grouped by category. To learn about each command, type "help" followed by the command name, e.g. "help set". Terms such as Command state and Connect state are explained in subsequent sections.

Optional fields are shown in [ brackets ]. "filename" means the name of a single file. filespec means a file specification that is allowed to contain wildcard characters like ’*’ to match groups of files. options are (optional) switches like /PAGE, /NOPAGE, /QUIET, etc, listed in the HELP text for each command. Example:

send /recursive /larger:10000 /after:-1week /except:*.txt *

which can be read as "send all the files in this directory and all the ones underneath it that are larger than 10000 bytes, no more than one week old, and whose names don’t end with ".txt".

Basic Commands

HELP command

Requests help about the given command.

INTRODUCTION

Requests a brief introduction to C-Kermit.

LICENSE

Displays the C-Kermit software copyright and license.

VERSION

Displays C-Kermit’s version number.

EXIT [ number ]

Exits from Kermit with the given status code (0 = success, nonzero = failure). Synonyms: QUIT, E, Q.

TAKE filename [ parameters... ]

Executes commands from the given file.

LOG item [ filename ]

Keeps a log of the given item (DEBUG, TRANSACTIONS, etc) in the given file.

[ DO ] macro [ parameters... ]

Executes commands from the given macro.

SET parameter value

Sets the given parameter to the given value.

SHOW category

Shows settings in a given category.

DATE [ date-and/or-time ]

Shows current date-time or interprets given date-time.

RUN [ extern-command [ parameters... ]

Runs the given external command. Synonym: !.

EXEC [ extern-command [ params... ]

Kermit overlays itself with the given command.

SUSPEND

Stops Kermit and puts it in the background. Synonym: Z.

Local File Management

TYPE [ options ] filename

Displays the contents of the given file.

MORE [ options ] filename

Equivalent to TYPE /PAGE (pause after each screenful).

CAT [ options ] filename

Equivalent to TYPE /NOPAGE.

HEAD [ options ] filename

Displays the first few lines of a given file.

TAIL [ options ] filename

Displays the last few lines of a given file.

GREP [ options ] pattern filespec

Displays lines from files that match the pattern. Synonym: FIND.

DIRECTORY [ options ] [filespec ]

Lists files (built-in, many options).

LS [ options ] [ filespec ]

Lists files (runs external "ls" command).

DELETE [ options ] [ filespec ]

Deletes files. Synonym: RM.

PURGE [ options ] [ filespec ]

Removes backup (*.~n~) files.

COPY [ options ] [ filespecs... ]

Copies files. Synonym: CP.

RENAME [ options ] [ filespecs... ]

Renames files. Synonym: MV.

CHMOD [ options ] [ filespecs... ]

Changes permissions of files.

TRANSLATE filename charsets [ filename ]

Converts file’s character set. Synonym: XLATE.

CD directory

Changes your working directory to the one given.

MKDIR [ directory ]

Creates a directory.

RMDIR [ directory ]

Removes a directory.

Making Connections

SET LINE [ options ] devicename

Opens the named serial port. Synonym: SET PORT.

OPEN LINE [ options ] devicename

Same as SET LINE. Synonym: OPEN PORT.

SET MODEM TYPE [ name ]

Tells Kermit what kind of modem is on the port.

DIAL [ number ]

Tells Kermit to dial the given phone number with the modem.

AUTHENTICATE [ parameters... ]

Performs secure authentication on a TCP/IP connection.

SET NETWORK TYPE { TCP/IP, X.25, ... }

Selects network type for subsequent SET HOST commands.

SET HOST [ options ] host [ port ]

Opens a network connection to the given host and port.

SET HOST * port

Waits for an incoming TCP/IP connection on the given port.

SSH [ options ] host

Opens a secure SSH connection to the host and enters Connect state.

TELNET [ options ] host

Opens a Telnet connection to the host and enters Connect state.

RLOGIN [ options ] host

Opens an Rlogin connection to the host and enters Connect state.

IKSD [ options ] host

Opens a connection to an Internet Kermit Service.

FTP OPEN host [ options ]

Opens an FTP connection to the host.

HTTP [ options ] OPEN host

Opens an HTTP connection to the host.

PTY external-command

Runs the command on a pseudoterminal as if it were a connection.

PIPE external-command

Runs the command through a pipe as if it were a connection.

Using Connections

CONNECT [ options ]

Enters Connect (terminal) state. Synonym: C.

REDIRECT command

Redirects the given external command over the connection.

TELOPT command

Sends a Telnet protocol command (Telnet connections only).

Ctrl-\C

"Escapes back" from Connect state to Command state.

Ctrl-\B

(In Connect state) Sends a BREAK signal (serial or Telnet).

Ctrl-\!

(In Connect state) Enters inferior shell; "exit" to return.

Ctrl-\?

(In Connect state) Shows a menu of other escape-level options.

Ctrl-\Ctrl-\

(In Connect state) Type two Ctrl-Backslashes to send one of them.

SET ESCAPE [ character ]

Changes Kermit’s Connect-state escape character.

Closing Connections

SET LINE (with no devicename)

Closes the currently open serial-port or network connection.

SET HOST (with no hostname)

Closes the currently open serial-port or network connection.

FTP CLOSE

Closes the currently open FTP connection.

HTTP CLOSE

Closes the currently open HTTP connection.

SET EXIT WARNING OFF

Suppresses warning about open connections on exit or close.

File Transfer

SEND [ options ] filename [ as-name ]

Sends the given file. Synonym: S.

SEND [ options ] filespec

Sends all files that match.

RESEND [ options ] filespec

Resumes an interrupted SEND from the point of failure.

RECEIVE [ options ] [ as-name ]

Waits passively for files to arrive. Synonym: R.

LOG TRANSACTIONS [ filename ]

Keeps a record of file transfers.

CAUTIOUS

Use cautious and less fast file-transfer settings.

STATISTICS [ options ]

Gives statistics about the most recent file transfer.

TRANSMIT [ options ] [ofilename ]

Sends file without protocol. Synonym: XMIT.

LOG SESSION [ filename ]

Captures remote text or files without protocol.

SET PROTOCOL [ name... ]

Tells Kermit to use an external file-transfer protocol.

FTP { PUT, MPUT, GET, MGET, ... }

FTP client commands.

HTTP { PUT, GET, HEAD, POST, ... }

HTTP client commands.

Kermit Server

ENABLE, DISABLE

Controls which server features can be used by clients.

SET SERVER

Sets parameters prior to entering Server state.

Client of Kermit or FTP Server

[ REMOTE ] LOGIN [ user password ]

Logs in to a Kermit server or IKSD that requires it.

[ REMOTE ] LOGOUT

Logs out from a Kermit server or IKSD.

SEND [ options ] filename [ as-name ]

Sends the given file to the server. Synonyms: S, PUT.

SEND [ options ] filespec

Sends all files that match.

RESEND [ options ] filespec

Resumes an interrupted SEND from the point of failure.

GET [ options ] remote-filespec

Asks the server to send the given files. Synonym: G.

REGET [ options ] remote-filespec

Resumes an interrupted GET from the point of failure.

REMOTE CD [ directory ]

Asks server to change its working directory. Synonym: RCD.

REMOTE PWD [ directory ]

Asks server to display its working directory. Synonym: RPWD.

REMOTE DIRECTORY [ filespec... ]

Asks server to send a directory listing. Synonym: RDIR.

REMOTE DELETE [ filespec... ]

Asks server to delete files. Synonym: RDEL.

REMOTE [ command... ]

(Many other commands: "remote ?" for a list).

MAIL [ options ] filespec

Sends file(s) to be delivered as e-mail (Kermit only).

Script Programming

DEFINE, DECLARE, UNDEFINE, UNDECLARE, ASSIGN, EVALUATE, SEXPRESSION, ARRAY, SORT, INPUT, OUTPUT, IF, FOR, WHILE, SWITCH, GOTO, ECHO, ASK, GETC, GETOK, ASSERT, WAIT, SLEEP, FOPEN, FREAD, FWRITE, FCLOSE, STOP, END, RETURN, LEARN, SHIFT, TRACE, VOID, INCREMENT, DECREMENT, ... For these and many more you’ll need to consult the manual and supplements, and/or visit the Kermit Script Library, which also includes a brief tutorial. Hint: HELP LEARN to find out how to get Kermit to write simple scripts for you.

Many of Kermit’s commands have synonyms, variants, relatives, and so on. For example, MSEND is a version of SEND that accepts a list of file specifications to be sent, rather than just one file specification, and MPUT is a synonym of MSEND. MOVE means to SEND and then DELETE the source file if successful. MMOVE is like MOVE, but accepts a list of filespecs, and so on. These are described in the full documentation.

Use question mark to feel your way through an unfamiliar command, as in this example:

C-Kermit> remote ? One of the following:
assign directory kermit print rmdir
cd exit login pwd set
copy help logout query space
delete host mkdir rename type
C-Kermit> remote set ? One of the following:
attributes file retry transfer
block-check receive server window
C-Kermit> remote set file ? One of the following:
character-set incomplete record-length
collision names type
C-Kermit> remote set file names ? One of the following:
converted literal
C-Kermit> remote set file names literal
C-Kermit>

This is called menu on demand: you get a menu when you want one, but menus are not forced on you even when know what you’re doing. Note that you can also abbreviate most keywords, and you can complete them with the Tab or Esc key. Also note that ? works for filenames too, and that you can use it in the middle of a keyword or filename, not just at the beginning. For example, "send x?" lists all the files in the current directory whose names start with ’x’.

INITIALIZATION FILE

In its default configuration, C-Kermit executes commands from a file called .kermrc in your home directory when it starts, unless it is given the -Y or -y command-line option. Custom configurations might substitute a shared system-wide initialization file. The SHOW FILE command tells what initialization file, if any, was used. The standard initialization file "chains" to an individual customization file, .mykermc, in the home directory, in which each user can establish her/his own preferences, define macros, and so on.

Since execution of the initialization file (at least the standard one) makes C-Kermit take longer to start, it might be better not to have an initialization file, especially now that Kermit’s default startup configuration is well attuned to modern computing and networking -- in other words, you no longer have do anything special to make Kermit transfers go fast. So instead of having an initialization file that is executed every time Kermit starts, you might consider making one or more kerbang scripts (with names other that .kermrc) that do NOT include an "exit" command, and invoke those when you need the settings, macro definitions, and/or scripted actions they contain, and invoke C-Kermit directly when you don’t.

MODES OF OPERATION

Kermit is said to be in Local mode if it has made a connection to another computer, e.g. by dialing it or establishing a Telnet connection to it. The other computer is remote, so if you start another copy of Kermit on the remote computer, it is said to be in Remote mode (as long as it has not made any connections of its own). The local Kermit communicates over the communications device or network connection, acting as a conduit between the remote computer and your keyboard and screen. The remote Kermit is the file-transfer partner to the local Kermit and communicates only through its standard input and output.

At any moment, a Kermit program can be in any of the following states. It’s important to know what they are and how to change from one to the other.
Command state

In this state, Kermit reads commands from:

• Your keyboard; or:
• A file, or:
• A macro definition.

You can exit from Command state back to Unix with the EXIT or QUIT command (same thing). You can enter Connect state with any of various commands (CONNECT, DIAL, TELNET, etc). You can enter file transfer state with commands like SEND, RECEIVE, and GET. You can enter Server state with the SERVER command. The TAKE command tells Kermit to read and execute commands from a file. The (perhaps implied) DO command tells Kermit to read and execute commands from a macro definition. While in Command state, you can interrupt any command, macro, or command file by typing Ctrl-C (hold down the Ctrl key and press the C key); this normally brings you back to the prompt.

Shell state

You can invoke an inferior shell or external command from the Kermit command prompt by using the PUSH, RUN (!), EDIT, or BROWSE command. While the inferior shell or command is active, Kermit is suspended and does nothing. Return to Kermit Command state by exiting from the inferior shell or application.

Connect state

In this state, which can be entered only when in Local mode (i.e. when Kermit has made a connection to another computer), Kermit is acting as a terminal to the remote computer. Your keystrokes are sent to the remote computer and characters that arrive over the communication connection are displayed on your screen. This state is entered when you give a CONNECT, DIAL, TELNET, SSH, or IKSD command. You can return to command state by logging out of the remote computer, or by typing:

Ctrl-\c

That is: Hold down the Ctrl key and press the backslash key, then let go of the Ctrl key and press the C key. This is called escaping back. Certain other escape-level commands are also provided; type Ctrl-\? for a list. For example, you can enter Shell state with:

Ctrl-\!

To send a Ctrl-\ to the host while in Connect state, type two of them in a row. See HELP CONNECT and HELP SET ESCAPE for more info.

Local file-transfer state

In this state, Kermit is sending packets back and forth with the other computer in order to transfer a file or accomplish some other file-related task. And at the same time, it is displaying its progress on your screen and watching your keyboard for interruptions. In this state, the following single-keystroke commands are accepted:

Kermit returns to its previous state (Command or Connect) when the transfer is complete or when interrupted successfully by X, Z, E, or Ctrl-C (hold down the Ctrl key and press the C key).
Remote file-transfer state

In this state, Kermit is exchanging file-transfer packets with its local partner over its standard i/o. It leaves this state automatically when the transfer is complete. In case you find your local Kermit in Connect state and the remote one in File-transfer state (in which it seems to ignore your keystrokes), you can usually return it to command state by typing three Ctrl-C’s in a row. If that doesn’t work, return your local Kermit to Command state (Ctrl-\ C) and type "e-packet" and then press the Return or Enter key; this forces a fatal Kermit protocol error.

Remote Server state

This is like Remote File-transfer state, except it never returns automatically to Command state. Rather, it awaits further instructions from the client program; that is, from your Local Kermit program. You can return the Remote Server to its previous state by issuing a "finish" command to the client, or if you are in Connect state, by typing three Ctrl-C’s in a row. You can tell the server job to log out and break the connection by issuing a "bye" command to the client.

Local Server state

Like Remote-Server state, but in local mode, and therefore with its file-transfer display showing, and listening for single-key commands, as in Local File-transfer state. Usually this state is entered automatically when a remote Kermit program gives a GET command.

C-Kermit, Kermit 95, and MS-DOS Kermit all can switch automatically from Connect state to Local File-transfer state when you initiate a file transfer from the remote computer by starting Kermit and telling it to send or get a file, in which case, Connect state is automatically resumed after the file transfer is finished.

Note that C-Kermit is not a terminal emulator. It is a communications application that you run in a terminal window (e.g. console or Xterm). The specific emulation, such as VT100, VT220, Linux Console, or Xterm, is provided by the terminal window in which you are running C-Kermit. Kermit 95 and MS-DOS Kermit, on the other hand, are true terminal emulators. Why is C-Kermit not a terminal emulator? CLICK HERE to read about it.

MAKING CONNECTIONS

Here is how to make different kinds of connections using interactive Kermit commands (as noted above, you can also make connections with command-line options). Note that you don’t have to make connections with Kermit. It can also be used on the far end of a connection as the remote file transfer and management partner of your local communications software.
Making a Telnet Connection

At the C-Kermit command prompt, simply type:

telnet foo.bar.com

(substituting desired hostname or address). You can also include a port number:

telnet xyzcorp.com 3000 ;

If the connection is successful, Kermit automically enters Connect state. When you logout from the remote host, Kermit automatically returns to its prompt. More info: HELP TELNET, HELP SET TELNET, HELP SET TELOPT. Also see the IKSD section below.

Making an Rlogin connection

This is just like Telnet, except you have to be root to do it because Rlogin uses a privileged TCP port:

rlogin foo.bar.com

More info: HELP RLOGIN.

Making an SSH Connection

Unlike Telnet and Rlogin, SSH connections are not built-in, but handled by running your external SSH client through a pseudoterminal. Using C-Kermit to control the SSH client gives you all of Kermit’s features (file transfer, character-set conversion, scripting, etc) over SSH.

ssh foo.bar.com

More info: HELP SSH, HELP SET SSH.

Dialing with a Modem

If it’s an external modem, make sure it is connected to a usable serial port on your computer with a regular (straight-through) modem cable, and to the telephone jack with a telephone cable, and that it’s turned on. Then use these commands:

set modem type usrobotics ; Or other supported type
set line /dev/ttyS0 ; Specify device name
set speed 57600 ; Or other desired speed
set flow rts/cts ; Most modern modems support this
set dial method tone ; (or pulse)
dial 7654321 ; Dial the desired number

Type "set modem type ?" for a list of supported modem types. If you omit the SET MODEM TYPE command, the default type is "generic-high-speed", which should work for most modern AT-command-set modems. If the line is busy, Kermit redials automatically. If the call does not succeed, use "set dial display on" and try it again to watch what happens. If the call succeeds, Kermit enters Connect state automatically and returns to its prompt automatically when you log out from the remote computer or the connection is otherwise lost.

You can also dial from a modem that is accessible by Telnet, e.g. to a reverse terminal server. In this case the command sequence is:

set host ts.xxx.com 2000 ; Terminal-server and port
set modem type usrobotics ; Or other supported type
set dial method tone ; (or pulse)
dial 7654321 ; Dial the desired number

If the terminal server supports the Telnet Com Port Option, RFC 2217, you can also give serial-port related commands such as SET SPEED, SET PARITY, and so on, and Kermit relays them to the terminal server using the protocol specified in the RFC.

More info: HELP SET MODEM, HELP SET LINE, HELP SET SPEED, HELP SET FLOW, HELP DIAL, HELP SET DIAL, HELP SET MODEM, HELP SET CARRIER-WATCH, SHOW COMMUNICATIONS, SHOW MODEM, SHOW DIAL.

Direct Serial Port

Connect the two computers, A and B, with a null modem cable (or two modem cables interconnected with a null-modem adapter or modem eliminator). From Computer A:

set modem type none ; There is no modem
set line /dev/ttyS0 ; Specify device name
set carrier-watch off ; If DTR CD are not cross-connected
set speed 57600 ; Or other desired speed
set flow rts/cts ; If RTS and CTS are cross-connected
set parity even ; (or "mark" or "space", if necessary)
set stop-bits 2 ; (rarely necessary)
set flow xon/xoff ; If you can’t use RTS/CTS
connect ; Enter Connect (terminal) state

This assumes Computer B is set up to let you log in. If it isn’t, you can run a copy of Kermit on Computer B and follow approximately the same directions. More info: As above plus HELP CONNECT.

With modems or direct serial connections, you might also have to "set parity even" (or "mark" or "space") if it’s a 7-bit connection.

Of the connection types listed above, only one can be open at a time. However, any one of these can be open concurrently with an FTP or HTTP session. Each connection type can be customized to any desired degree, scripted, logged, you name it. See the manual.

NOTE: On selected platforms, C-Kermit also can make X.25 connections. See the manual for details.

TRANSFERRING FILES WITH KERMIT

There is a widespread and persistent belief that Kermit is a slow protocol. This is because, until recently, it used conservative tuning by default to make sure file transfers succeeded, rather than failing because they overloaded the connection. Some extra commands (or command-line options, like -Q) were needed to make it go fast, but nobody bothered to find out about them. Also, it takes two to tango: most non-Kermit-Project Kermit protocol implementations really ARE slow. The best file-transfer partners for C-Kermit are: another copy of C-Kermit (7.0 or later) on Unix, (Open)VMS, or Microsoft Windows (formerly known as Kermit 95 or K95, now in Open Source release as C-Kermit 10.0 for Windows or CKW). These combinations work well and they work fast by default. MS-DOS Kermit is good too, but you have to tell it to go fast (by giving it the FAST command).

Furthermore, all three of these Kermit programs support "autodownload" and "autoupload", meaning that when they are in Connect state and a Kermit packet comes in from the remote, they automatically switch into file transfer mode.

And plus, C-Kermit switches automatically between text and binary mode for each file, so there is no need to "set file type binary" or "set file type text", or to worry about files being corrupted because they were transferred in the wrong mode.

What all of these words add up to is that now, when you use up-to-date Kermit software from the Kermit Project, file transfer is not only fast, it’s ridiculously easy. You barely have to give any commands at all.

Downloading Files

Let’s say you have C-Kermit for Unix or VMS, CKW for Windows, or MS-DOS Kermit on your desktop computer, with a connection to a Unix computer that has C-Kermit installed as "kermit". To download a file (send it from Unix to your desktop computer), just type the following command at your Unix shell prompt:

kermit -s somefile.txt

(where somefile.txt is the filename). If you want to send more than one file, you can put as many filenames as you want on the command line, and they can be any combination of text and binary:

kermit -s somefile.txt somefile.zip somefile.html somefile.tar.gz

and/or you can use wildcards to send groups of files:

kermit -s somefile.*

If you want to send a file under an assumed name, use:

kermit -s friday.txt -a today.txt

This sends the file friday.txt but tells the receiving Kermit that its name is today.txt. In all cases, as noted, when the file transfer is finished, your desktop Kermit returns automatically to Connect state. No worries about escaping back, re-connecting, text/binary mode switching. Almost too easy, right?

Uploading Files

To upload files (send them from your desktop computer to the remote Unix computer) do the same thing, but use the -g (GET) option instead of -s:

kermit -g somefile.txt

This causes your local Kermit to enter server mode; then the remote Kermit program requests the named file and the local Kermit sends it and returns automatically to Connect state when done.

If you want to upload multiple files, you have to use shell quoting rules, since these aren’t local files:

kermit -g "somefile.txt somefile.zip somefile.html somefile.tar.gz"
kermit -g "somefile.*"

If you want to upload a file but store it under a different name, use:

kermit -g friday.txt -a today.txt

Kermit Transfers the Old-Fashioned Way

If your desktop communications software does not support autoupload or autodownload, or it does not include Kermit server mode, the procedure requires more steps.

To download a file, type:

kermit -s filename

on the host as before, but if nothing happens automatically in response to this command, you have to switch your desktop communications software into Kermit Receive state. This might be done by escaping back using keyboard characters or hot keys (Alt-x is typical) and/or with a command (like RECEIVE) or a menu. When the file transfer is complete, you have to go back to Connect state, Terminal emulation, or whatever terminology applies to your desktop communications software.

To upload a file, type:

kermit -r

on the host (rather than "kermit -g"). This tells C-Kermit to wait passively for a file to start arriving. Then regain the attention of your desktop software (Alt-x or whatever) and instruct it to send the desired file(s) with Kermit protocol. When the transfer is finished, return to the Connect or Terminal screen.

If File Transfer Fails

Although every aspect of Kermit’s operation can be finely tuned, there are also three short and simple "omnibus tuning" commands you can use for troubleshooting:

CAUTIOUS

Use cautious but not paranoid settings. File transfers, if they work, will go at medium speed. If not, try . . .

Obviously the success and performance of a file transfer also depends on C-Kermit’s file transfer partner. Up-to-date, real Kermit Project partners are recommended because they contain the best Kermit protocol implementations and because we can support them in case of trouble.

If you still have trouble, consult Chapter 10 of Using C-Kermit, or send email to upport [AT] kermitproject.org.

Advanced Kermit File-Transfer Features

Obviously there is a lot more to Kermit file transfer, including all sorts of interactive commands, preferences, options, logging, debugging, troubleshooting, and anything else you can imagine but that’s what the manual and updates are for. Here are a few topics you can explore if you’re interested by Typing HELP for the listed commands:

Logging transfers:

LOG TRANSACTIONS (HELP LOG)

Automatic per-file text/binary mode switching:

SET TRANSFER MODE { AUTOMATIC, MANUAL } (HELP SET TRANSFER).

Cross-platform recursive directory tree transfer:

SEND /RECURSIVE, GET /RECURSIVE (HELP SEND, HELP GET).

File collision options:

SET FILE COLLISION { OVERWRITE, BACKUP, DISCARD, ... } (HELP SET FILE).

Update: Transfer only files that changed since last time:

SET FILE COLLISION UPDATE (HELP SET FILE).

Filename selection patterns:

(HELP WILDCARD).

Flexible file selection:

SEND (or GET) /BEFORE /AFTER /LARGER /SMALLER /TYPE /EXCEPT, ...

Character-set conversion:

SET { FILE, TRANSFER } CHARACTER-SET, ASSOCIATE, ...

File/Pathname control:

SET { SEND, RECEIVE } PATHNAMES, SET FILE NAMES.

Atomic file movement:

SEND (or GET) /DELETE /RENAME /MOVE-TO

Transferring to/from standard i/o of other commands:

SEND (or GET) /COMMAND

Recovery of interrupted transfer from point of failure:

RESEND, REGET (HELP RESEND, HELP REGET).

Non-Kermit File Transfer

You can also use C-Kermit to transfer files with FTP or HTTP Internet protocols; see below.

On a regular serial or Telnet connection where the other computer doesn’t support Kermit protocol at all, you have several options. For example, if your desktop communications software supports Zmodem, use "rz" and "sz" on the host rather than Kermit. But if Kermit is your desktop software, and you are using it to make calls or network connections to other computers that don’t support Kermit protocol (or that don’t have a good implementation of it), then if your computer also has external X, Y, or Zmodem programs that are redirectable, Kermit can use them as external protocols. HELP SET PROTOCOL for details.

You can also capture "raw" data streams from the other computer with LOG SESSION (HELP LOG and HELP SET SESSION-LOG for details), and you can upload files without any protocol at all with TRANSMIT (HELP TRANSMIT, HELP SET TRANSMIT).

KERMIT’S BUILT-IN FTP AND HTTP CLIENTS

Kermit’s FTP client is like the regular Unix FTP client that you’re used to, but with some differences:

The Kermit FTP client is thoroughly documented at the Kermit Project website:

https://kermitproject.org/ftpclient.html

You also can use HELP FTP and HELP SET FTP to get descriptions of Kermit’s FTP-related commands.

The HTTP client is similar to the FTP one, except you prefix each command with HTTP instead of FTP: HTTP OPEN, HTTP GET, HTTP PUT, HTTP CLOSE, etc. Type HELP HTTP for details, or visit the to view the manual supplements. HTTP connections can be open at the same time as regular serial or Telnet connections and FTP connections. So Kermit can manage up to three types connections simultaneously.

INTERNET KERMIT SERVICE

C-Kermit can be configured and run as an Internet service (called IKSD), similar to an FTP server (FTPD) except you can (but need not) interact with it directly, plus it does a lot more than an FTP server can do. The TCP port for IKSD is 1649. It uses Telnet protocol. C-Kermit can be an Internet Kermit Server, or it can be a client of an IKSD. You can make connections from C-Kermit to an IKSD with any of the following commands:

telnet foo.bar.edu 1649
telnet foo.bar.edu kermit ; if "kermit" is listed in /etc/services
iksd foo.bar.edu

The IKSD command is equivalent to a TELNET command specifying port 1649. For more information about making and using connections to an IKSD, see:

https://kermitproject.org/cuiksd.html

You can run an Internet Kermit Service on your own computer too (if you are the system administrator). For instructions, see:

https://kermitproject.org/iksd.html

SECURITY

All of C-Kermit’s built-in TCP/IP networking methods (Telnet, Rlogin, IKSD, FTP, and HTTP) can be secured by one or more of the following IETF-approved methods:

The Windows version of C-Kermit 10.0 (CKW) has its own built-in SSH client; the Unix version makes SSH connections through the external SSH client.

For complete instructions see:

https://kermitproject.org/security.html

ALTERNATIVE COMMAND-LINE PERSONALITIES

When invoked as "kermit" or any other name besides "ftp" or "telnet", C-Kermit has the command-line options described above in the OPTIONS section. However, if you invoke C-Kermit as "telnet" or "ftp", it changes its command-line personality to match. This can be done (among other ways) with symbolic links (symlinks). For example, if you want C-Kermit to be your regular Telnet client, or the Telnet helper of your Web browser, you can create a link like the following in a directory that lies in your PATH ahead of the regular telnet program:

ln -s /usr/local/bin/kermit telnet

Now when you give a "telnet" command, you are invoking Kermit instead, but with its Telnet command-line personality so, for example:

telnet xyzcorp.com

Makes a Telnet connection to xyzcorp.com, and Kermit exits automatically when the connection is closed (just like the regular Telnet client). Type "telnet -h" to get a list of Kermit’s Telnet-personality command-line options, which are intended to be as compatible as possible with the regular Telnet client.

Similarly for FTP:

ln -s /usr/local/bin/kermit ftp

And now type "ftp -h" to see its command-line options, and command lines just like you would give your regular FTP client:

ftp xyzcorp.com

but with additional options allowing an entire session to be specified on the command line. Finally, if Kermit’s first command-line option is a Telnet, FTP, IKSD, or HTTP URL, Kermit automatically makes the appropriate kind of connection and, if indicated by the URL, takes the desired action:
kermit telnet:xyzcorp.com

Opens a Telnet session

kermit telnet://olga [AT] xyzcorp.com

Ditto for user olga

kermit ftp://olga [AT] xyzcorp.com/public/somefile.zip

Downloads a file

kermit https://kermitproject.org/index.html

Grabs a web page

LICENSE

As of version 9.0 C-Kermit carries the Revised 3-Clause BSD License, which is 100% Open Source. C-Kermit’s LICENSE command displays the license, and it is also available on the Kermit Project website:
kermit https://kermitproject.org/ck10license.html

OTHER TOPICS

There’s way more to C-Kermit than we’ve touched on here -- troubleshooting, customization, character sets, dialing directories, sending pages, script writing, and on and on, all of which are covered in the manual and updates and supplements. For the most up-to-date information on documentation (or updated documentation itself) visit the Kermit Project website:

https://kermitproject.org/

There you will also find Kermit software packages for other platforms: different Unix varieties, Windows, DOS, VMS, IBM mainframes, and many others: over 40 years’ worth at this writing (2022).

DOCUMENTATION AND UPDATES

The manual for C-Kermit is:
Using C-Kermit

Frank da Cruz and Christine M. Gianone, Second Edition, Digital Press / Butterworth-Heinemann, Woburn, MA, 1997, 622 pages, ISBN 1-55558-164-1. This is a printed book. It covers C-Kermit 6.0. As of 2016 it is also available online in PDF form:

https://www.kermitproject.org/onlinebooks/usingckermit3e.pdf

The C-Kermit 7.0 Supplement

https://kermitproject.org/ckermit70.html

The C-Kermit 8.0 Supplement

https://kermitproject.org/ckermit80.html

The C-Kermit 9.0 Supplement

https://kermitproject.org/ckermit90.html

The C-Kermit 10.0 Specifications

https://kermitproject.org/ck10specs.html

The C-Kermit 10.0 Complete Command List

https://kermitproject.org/ck10commandref.html

Visit the C-Kermit home page:

https://kermitproject.org/ckermit.html

to learn about new versions, Beta tests, and other news; to read case studies and tutorials; to download source code, install packages, and prebuilt binaries for many platforms. Also visit:
https://kermitproject.org/ckscripts.html

The Kermit script library and tutorial

https://kermitproject.org/ckfaq.html

The C-Kermit FAQ (Frequently Asked Questions about C-Kermit)

https://kermitproject.org/telnet.html

C-Kermit Telnet client documentation

https://kermitproject.org/security.html

C-Kermit security documentation (Kerberos, SSL/TLS, etc)

https://kermitproject.org/cuiksd.html

Internet Kermit Service user documentation

https://kermitproject.org/iksd.html

Internet Kermit Service administrator documentation

https://kermitproject.org/studies.html

Case studies.

https://kermitproject.org/support.html

Technical support.

https://kermitproject.org/ckuins.html.

Installation instructions for Unix.

https://kermitproject.org/ckcbwr.html.

General C-Kermit bugs, hints, tips.

https://kermitproject.org/ckubwr.html.

Unix-specific C-Kermit bugs, hints, tips.

https://kermitproject.org/ckcplm.html.

C-Kermit program logic manual.

https://kermitproject.org/ckccfg.html.

C-Kermit compile-time configuration options.

/var/spool/locks (or whatever)

UUCP lockfile for dialing out (see installation instructions).

ca_certs.pem

Certificate Authority certifcates used for SSL connections.

AUTHORS

Software

Frank da Cruz and Jeffrey E Altman,
1985-present, with contributions from hundreds of others all over the world, notably David Goodwin for converting the 2001 edition of Kermit 95 to Open Source C-Kermit 10.0 for Windows.

Documentation

Frank da Cruz

Address

The Open Source Kermit Project
Bronx NY
USA