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since 1981


Frank da Cruz
The Kermit Project
Also see: C-Kermit 10.0 command reference

Most recent update: Wed Feb 28 08:55:47 2024


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C-Kermit is an all-purpose communications software package from the Kermit Project that:
  • Is portable to Unix, Windows, and (Open)VMS.
  • Can make both serial and network connections.
  • Can conduct interactive terminal sessions over its connection.
  • Can transfer text or binary files over the same connection.
  • Can convert text-file character sets in terminal mode or file transfer.
  • Is customizable in every aspect of its operation.
It is called C-Kermit because it is written in C programming language. C-Kermit is an interactive text-mode terminal and file-transfer transfer program with its own built-in scripting (programming) language that lets you automate common or complicated tasks. It was first written at Columbia University's Kermit Project in 1985 and has been developed continuously through ten major new releases.

"Text-mode" means it is to be used in a Unix shell, VMS console session, etc, in the manner that most software was used during the timesharing era, approximately mid-1970s to mid-1990s, and which is still used today by software developers, system administrators, website authors, and old diehards. Until 2011, C-Kermit was free but with some licensing restrictions. Since 2011 it is 100% Open Source, and since 2022 the Windows version is also free and Open Source.

C-Kermit is cable of making many different kinds of connections, including direct serial-port, dialup modem, and Intenet. On the Internet C-Kermit can make secure SSH connections and (if you can find servers for them), secure Telnet and FTP connections too.

C-Kermit can be:

  • Your terminal emulation and file transfer application on desktop Unix or VMS or Windows sytems;
  • The far-end file-transfer or client/server partner of your desktop Kermit client.
  • Your programming language... yes, really!
And 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 [RFC 2839, RFC 2840].

And perhaps most important, everything you can do by hand (interactively) with C-Kermit, can be automated using its built-in cross-platform transport-independent script programming language. CLICK HERE for an introduction to Kermit script programming.

Over the years, C-Kermit was available for a large variety of operating systems and variants (and still is), but the vast proliferation of different computers and OS's of the 1980s-90s has dwindled to just a handful today, primarily Unix (Linux, Mac OS, BSD, etc), (Open)VMS, and Microsoft Windows. C-Kermit 10.0 is available for all of these.


C-Kermit's interactive command language is the subject of a 622-page book and another several hundred pages of updates. But it's not hard to get started. At the shell prompt, just type "kermit" to get C-Kermit's interactive command prompt (or on Windows or OS/2, double-click the C-Kermit's icon)

$ 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 partially typed 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, and who knows what else. Give the INTRO command for details.

Use question mark to feel your way through an unfamiliar command, as in this example (the part you type is underlined):

C-Kermit> remote ? One of the following:
   assign     delete     help       login      print      rename     space
   cd         directory  host       logout     pwd        rmdir      type
   copy       exit       kermit     mkdir      query      set        who
  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

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'.

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

  • Making connections (SET LINE, DIAL, TELNET, SSH, FTP, CONNECT, ...)
  • Breaking connections (HANGUP, CLOSE)
  • Transferring files (SEND, GET, RECEIVE, MOVE, RESEND, ...)
  • Establishing preferences (SET)
  • Displaying preferences (SHOW)
  • Managing local files (CD, DELETE, MKDIR, DIRECTORY, RENAME, TYPE, COPY, TOUCH, ...)
  • Managing remote files (RCD, RDEL, RMKDIR, RDIR, ...)
  • Using local files (FOPEN, FCLOSE, FREAD, FWRITE)
  • Programming (TAKE, DEFINE, IF, FOR, WHILE, SWITCH, DECLARE, ...)
  • Interacting with the user (ECHO, ASK, ...)
  • Interacting with a remote computer (INPUT, OUTPUT, ...)
  • Interacting with local programs (RUN, EXEC, PTY, ...)
  • Logging things (LOG SESSION, LOG PACKETS, LOG DEBUG, ...)

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 all the rest. 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
It also introduces variable names and calls to built-in functions.

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..."

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

./commandfile one two three four five


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

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). Here's a simple example:

define mydial {
    set modem type usrobotics
    set port /dev/ttyS0
    if fail end 1
    set speed 57600
    dial \%1
    if success connect

This shows how you can combine many commands into one command, "mydial" in this case (you can use any name you like, provided it does not clash with the name of a built-in command). When this macro definition is in effect, you can type commands like:

mydial 7654321

and it executes all the commands in macro definition, substituting the first operand ("7654321") for the formal parameter ("\%1") in the definition. This saves you from having to type lots of commands every time you want to make a modem call.

One way to have the macro definition in effect is to type the definition at the Kermit prompt. Another way is to store the definition in a file and TAKE the file. If you want the definition to be in effect automatically every time you start Kermit, put the definition in your initialization file (explained below).

Here's a somewhat more ambitious example:

define mydelete {
    local trash
    if not defined \%1 end 1 "Delete what?"
    assign trash \v(home)trashcan/
    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 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, they can check them and make other kinds of decisions, and the commands themselves are relatively intuitive and intelligible.

If you put the above lines into your initializatio file, 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    (Unix example; see table for others)
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, and they are listed HERE. Meanwhile, 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".

In the following [ brackets ] indicate optional fields and { xxx, yyy, zzz } indicates a list of choices.

Basic commands...
HELP Requests top-level help.
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. Synonyms: QUIT, E, Q.
TAKE filename [ parameters... ] Executes commands from the given file.
[ DO ] macroname [ 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.
STATUS Tells whether previous command succeeded or failed.
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 (Unix only) 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.
CONVERT filename charsets [ filename ] Converts file's character set = TRANSLATE, XLATE.
CD Changes your working directory to your home directory.
CD directory Changes your working directory to the one given.
CDUP Changes your working directory one level up.
PWD Displays your working directory.
BACK Returns to your previous working directory.
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.
REDIAL Redials the most recently dialed phone number.
ANSWER Waits for and answers an incoming call on 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 [ options ] * port Waits for an incoming TCP/IP connection on the given port.
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.
SSH [ options ] host Opens an SSH connection to the host and enters Connect state.
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
HANGUP Hangs up the currently open serial-port or network connection.
CLOSE Closes the currently open serial-port or network connection.
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.
EXIT Also closes all connections. Synonym: QUIT.
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.
FAST Use fast file-transfer settings (default).
CAUTIOUS Use cautious and less fast file-transfer settings.
ROBUST Use ultra-conservative and slow file-transfer settings.
STATISTICS [ options ] Gives statistics about the most recent file transfer.
WHERE After transfer: "Where did my files go?".
TRANSMIT [ options [ filename ] Sends file without protocol. Synonym: XMIT.
LOG SESSION [ filename ] Captures remote text or files without protocol.
SET PROTOCOL [ name ] Tells Kermit to use the named 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 features can be used by clients.
SET SERVER Sets parameters prior to entering Server state.
SERVER Enters 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).
FINISH Asks the server to exit server state (Kermit only).
BYE Asks the server to log out and close the connection.

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 C-Kermit 10.0 Command Reference, 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.


When you start C-Kermit, it executes commands from an initialization file in your home directory unless it is given the -Y or -y command-line option.
Platform Filename Location
Unix (Linux, BSD, macOS, etc) .kermrc Your home (login) directory
MS Windows k95custom.ini \v(appdata) (your application data directory)
IBM OS/2 k2custom.ini \v(appdata) (your application data directory)
VMS, OpenVMS ckermit.ini Your home (login) directory
Other ckermit.ini Your home (login) directory
Your initialization file can contain any Kermit commands at all, as well as comments. A typical use would be to define macros that you want to be able to execute whenever you're using C-Kermit. To remind you that it's being executed you might want to include a line like this in it:
echo C-Kermit \v(fullversion) executing \v(cmdfile)...


Kermit is said to be in Local mode if it has made a connection to another computer, e.g. by dialing it or establishing an SSH or Telnet connection to it. Think of "local" as meaning "where you are". The local Kermit is the one you're using directly.

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 with it over the communications device or network connection, acting as a conduit between the 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 (SSH, 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, SSH, TELNET, RLOGIN, or IKSD command. You can return to command state by logging out of the remote computer, or by typing:
Unix, VMS Ctrl-\c
Windows, OS/2 Ctrl-[c or Alt-x or the Back-and-forth-arrows icon icon.
"Ctrl-\x" means "Hold down the Ctrl (Control) key and press the backslash key, then press the '\' or '[' (Ctrl can be up or down). This is called escaping back. Certain other escape-level commands are also provided; type Ctrl-\? (Unix, VMS) or Ctrl-[? (Windows, OS/2) for help.

To send a Ctrl-\ or 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 over the communication connection 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:

  X Interrupt the current file and go on to the next (if any).
  Z Interrupt the current file and skip all the rest.
  E Like Z but uses a "stronger" protocol (use if X or Z don't work).
  Ctrl-C   Interrupt file-transfer mode (use if Z or E don't work).

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, the remote 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, unless there was an error, in which case it stays in its file transfer screen so you can see what the error was.

Note that (except on Windows and OS/2) 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.


Here is how to make different kinds of connections using interactive Kermit commands (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 an SSH Connection
The Windows version of C-Kermit 10.0 has its own built-in SSH (Secure Shell) protocol with tons of options and features; type "help ssh" at its prompt for details. If you want to set up secure key exchange that permits "passwordless login" see THIS PAGE.

In Unix and VMS, 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            ; Substitute desired host name or address.


Making a Telnet Connection
At the C-Kermit command prompt, simply type:

telnet foo.bar.com         ; Substitute desired host name or address.
telnet xyzcorp.com 3000    ; You can also include a port number.

If the connection is successful, Kermit automatically 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         ; Substitute desired host name or address.

More info: HELP RLOGIN.

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.


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 and CD are not cross-connected
set speed 57600            ; Or other desired speed
set flow rts/cts           ; If RTS and CTS are cross-connected
set flow xon/xoff          ; If you can't use RTS/CTS
set parity even            ; (or "mark" or "space", if necessary)
set stop-bits 2            ; (rarely necessary)
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.


There is a widespread and persistent belief that Kermit is a slow protocol. This is because, for its first decade or so (1980-1990), 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) and Kermit 95. 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 and K95 also switch 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 Kermit 95, C-Kermit, 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 on the remote computer:

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 have 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:

Use fast file-transfer settings. This has been the default since C-Kermit 7.0 (January 2000) now that most modern computers and connections support it. If transfers fail with fast settings, try...

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

Use the most robust, resilient, conservative, safe, and reliable settings. File transfers will almost certainly work, but they will be quite slow (of course this is a classic tradeoff; ROBUST was C-Kermit's default tuning in versions 6.0 and earlier, which made everybody think Kermit protocol was slow). If ROBUST doesn't do the trick, try again with SET PARITY SPACE first in case it's not an 8-bit connection.

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.

If you still have trouble, consult Chapter 10 of Using C-Kermit, or send email to support@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:

Automatic per-file text/binary mode switching:

Cross-platform recursive directory tree transfer:

File collision options:

Update mode (only transfer files that changed since last time):

Filename selection patterns:

Flexible file selection:

Character-set conversion:

File/Pathname control:

Atomic file movement:

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

Recovery of interrupted transfer from point of failure:

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).


On any kind of connection you can make with Kermit -- serial, TCP/IP, X.25, etc -- you can set up a convenient client/server relationship between your Kermit client (the one that made the connection) and the Kermit program on the far end of the connection (the remote Kermit) by putting the remote Kermit in server mode. This is normally done by giving it a SERVER command, or by starting it with the -x command-line option. In some cases (Internet Kermit Service, SSH connections to a Kermit subsystem, or specially configured hosts), there is already a Kermit server waiting on the far end. Here is a quick synopsis of the commands you can give to the client for interacting with the server:

SEND [ switches ] filename
Sends the named file to the server. The filename can include wildcards. Lots of switches are available for file selection, etc. Type HELP SEND at the client prompt for details.

GET [ switches ] filename
Asks the server to send the named file. The filename can include wildcards. Type HELP GET at the client prompt for details.

Terminates the server and closes your connection to it.

Terminates the server. If you started the server yourself, this leaves the remote host at its shell prompt. If it was a dedicated server (such as IKSD or an SSH subsystem), FINISH is equivalent to BYE.

(C-Kermit 8.0.201 and later, K95 1.1.21 and later) This tells the client whether file-management commands like CD, PWD, DIRECTORY, DELETE, MKDIR, etc, should be executed locally or by the server. In this type of connection, the default is LOCAL. Use SET LOCUS REMOTE if you want Kermit to behave like an FTP client, in which case these commands are executed remotely, and their local versions must have an L prefix: LCD, LPWD, LDIRECTORY, etc. When LOCUS is LOCAL, then the remote versions must have an R prefix: RCD, RPWD, RDIRECTORY, etc. HELP SET LOCUS for details. SHOW COMMAND to see current locus.
The following commands are affected by SET LOCUS:

Change (working, current) directory. HELP CD for details.

CD one level up.

Produce a directory listing. Many options are available for local listings. HELP DIRECTORY for details.

Deletes files or directories. Many options available, HELP DELETE.

Renames files or directories. Many options available, HELP RENAME.

Creates a directory. HELP MKDIR.

Removes a directory. HELP RMDIR.
There are dozens -- maybe hundreds -- of other commands, described in the built-in help, on the website, and/or in the published or online manuals. But even if you don't have access to documentation, you can "set locus remote" and then use pretty much the same commands you would use with any FTP client.


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

  • It has lots more commands and features.
  • You can have an FTP session and a regular Kermit serial or SSH or Telnet session open at the same time.
  • FTP sessions can be fully automated.

By default Kermit's FTP client tries its best to present the same user interface as a regular FTP client: PUT, GET, DIR, CD, BYE, etc, should work the same, even though some of these commands have different meaning in Kermit-to-Kermit connections; for example, CD, DIR, RENAME, etc, in Kermit act locally, whereas in FTP they are commands for the server. This might cause some confusion, but as in all things Kermit, you have total control:

  • The SET LOCUS command lets you specify where file management commands should be executed -- locally or remotely -- for any kind of connection.
  • Any FTP command can be prefixed with the word "FTP" to remove any ambiguity.

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


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.

FTP Client HTTP Client


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:


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



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:

  • MIT Kerberos IV
  • MIT Kerberos V
  • Stanford SRP

For complete instructions see:


And as noted previously, you can also make SSH connections with C-Kermit if you already have an SSH client installed.


When invoked as "kermit" or any other name besides any of the special ones, C-Kermit has the command-line options described above in the OPTIONS section. However, if you invoke C-Kermit using any of the following names:

  telnet  Telnet client
  ftp     FTP client
  http    HTTP client
  https   Secure HTTP client

Kermit's command-line personality changes 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 use command lines just like you would give your regular FTP client:

ftp -n xyzcorp.com

but with additional options allowing an entire session to be specified on the command line, as explained in the C-Kermit FTP client documentation.

And similarly for HTTP:

ln -s /usr/local/bin/kermit http
./http -h
./http kermitproject.org -g kermit/index.html

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@xyzcorp.com                     ; Ditto for user olga
kermit ftp://olga@xyzcorp.com/public/somefile.zip    ; Downloads a file
kermit kermit://kermit.columbia.edu/kermit/f/READ.ME ; Ditto for IKSD
kermit iksd://kermit.columbia.edu/kermit/f/READ.ME   ; (This works too)
kermit https://kermitproject.org/index.html       ; Grabs a web page
kermit https://wwws.xyzcorp.com/secret/plan.html     ; Grabs a secure web page


Usage:  kermit [filename] [-x arg [-x arg]...[-yyy]..] [ {=,--,+} text ] ]
Or:    kermit URL

  • -x is an option requiring an argument;
  • -y is an option with no argument.

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:

  1. The command file (if any).
  2. The initialization file, if any, unless suppressed with -Y.
  3. The customization file (if it is executed by the initialization file).
  4. The command-line URL (if any, and if so, execution stops here).
  5. Command-line options (if any).
  6. Interactive commands.

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 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.)

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). The Action? column contains Y for action options and N for non-action options.

Option Action? Description
-0 N (digit zero) 100% transparent Connect state for "in-the-middle" operation: 8 bits, no parity, no escape character, everything passes through.
-8 N (digit eight) Connection is 8-bit clean (this is the default in C-Kermit 9.0 and later). Equivalent to the EIGHTBIT command, which in turn is a shortcut for SET TERMINAL BYTESIZE 8, SET COMMAND BYTESIZE 8, SET PARITY NONE.
-9 arg N (digit nine) Make a connection to an FTP server. Equivalent to the FTP OPEN command.
Argument: IP-address-or-hostname[:optional-TCP-port].
NOTE: C-Kermit also has a separate FTP command-line personality, with regular FTP-like command-line syntax. More about this below.
-A N Kermit is to be started as an Internet service (IKSD) (only from inetd.conf).
-B N Kermit is running in Batch or Background (no controlling terminal). To be used in case Kermit doesn't automatically sense its background status. Equivalent to the SET BACKGROUND ON command.
-C arg N Interactive-mode Commands to be executed.
Argument: Commands separated by commas, list in doublequotes.
-D arg N Delay before starting to send in Remote mode. Equivalent to the SET DELAY command.
Argument: Number of seconds.
-E N Exit automatically when connection closes. Equivalent to SET EXIT ON-DISCONNECT ON.
-F arg N Use an open TCP connection.
Argument: Numeric file descriptor of open TCP connection.
Also see: -j, -J.
-G arg Y Get file(s) from server, send contents to standard output, which normally would be piped to another process.
Argument: Remote file specification, in quotes if it contains metacharacters.
Also see: -g, -k.
-H N Suppress program startup Herald and greeting.
-I N Tell Kermit it has a reliable connection, to force streaming to be used where it normally would not be. Equivalent to the SET RELIABLE ON command.
-J arg N "Be like Telnet." Like -j but implies -E.
Argument: IP hostname/address optionally followed by service.
NOTE: C-Kermit also has a separate Telnet command-line personality, with regular Telnet-like command-line syntax. More about this below.
-L N Recursive directory descent for files in -s option.
-M arg N My user name (for use with Telnet, Rlogin, FTP, etc). Equivalent to the SET LOGIN USER command.
Argument: Username string.
-O Y (Uppercase letter O) Be a server for One command only. Also see: -x.
-P N Don't convert file (Path) names of transferred files. Equivalent to SET FILE NAMES LITERAL.
-Q N Quick Kermit protocol settings. Equivalent to the FAST command. This is the default in C-Kermit 7.0 and later.
-R N Remote-only (this just makes IF REMOTE true).
-S N Stay (enter command parser after action options).
-T N Force Text mode for file transfer; implies -V. Equivalent to SET TRANSFER MODE MANUAL, SET FILE TYPE TEXT.
-V N Disable automatic per-file text/binary switching. Equivalent to SET TRANSFER MODE MANUAL.
-Y N Skip (don't execute) the initialization file.
-a arg N As-name for file(s) in -s, -r, or -g.
Argument: As-name string (alternative filename). When receiving files, this can be a directory name.
-b arg N Speed for serial device. Equivalent to SET SPEED.
Argument: Numeric Bits per second for serial connections.
-c Y Enter Connect state before transferring files.
-d N Create a debug.log file with detailed debugging information (a second -d adds timestamps). Equivalent to LOG DEBUG but takes effect sooner.
-e arg N Maximum length for incoming Kermit file-transfer packets. Equivalent to SET RECEIVE PACKET-LENGTH.
Argument: Length in bytes.
-f Y Send a FINISH command to a Kermit server.
-g arg N Get file(s) from a Kermit server.
Argument: File specification on other computer, in quotes if it contains metacharacters. Equivalent to GET.
Also see: -a, -G, -r.
-h Y Print Help text for single-letter command-line options (pipe thru 'more' to prevent scrolling).
-i N Force binary (Image) mode for file transfer; implies -V. Equivalent to SET TRANSFER MODE MANUAL, SET FILE TYPE BINARY.
-j arg N Make a TCP/IP connection.
Argument: IP host name/address and optional service name or number. Equivalent to the TELNET command.
Also see: -J, -F.
-k Y Receive file(s) to standard output, which normally would be piped to another process.
Also see: -r, -G.
-l arg N (Lowercase letter L) Make a connection on the given serial communications device. Equivalent to the SET LINE (SET PORT) command.
Argument: Serial device name, e.g. /dev/ttyS0.
-m arg N Modem type for use with the -l device. Equivalent to the SET MODEM TYPE command.
Argument: Modem name as in SET MODEM TYPE command, e.g. "usrobotics".
-n Y Enter Connect state after transferring files (historical).
-p arg N Parity. Equivalent to the SET PARITY command.
Argument: One of the following: e(ven), o(dd), m(ark), n(one), s(pace).
-q N Quiet (suppress most messages). Equivalent to SET QUIET ON.
-r Y Receive file(s). Equivalent to the RECEIVE command.
Argument: (none, but see -a)
-s arg N Send file(s).
Argument: One or more local file specifications. Equivalent to the SEND command.
Also see: -a.
-t N (Historical) Xon (Ctrl-Q) Turnaround character for half-duplex connections (used on serial linemode connections to old mainframes). Equivalent to SET DUPLEX HALF, SET HANDSHAKE XON.
-v arg N Window size for Kermit protocol (ignored when streaming). Equivalent to SET WINDOW-SIZE.
Argument: Number, 1 to 32.
-w N Incoming files Write over existing files. Equivalent to SET FILE COLLISION OVERWRITE.
-x Y Enter server mode. Equivalent to the SERVER command. Also see: -O.
-y arg N Alternative initialization file.
Argument: Filename.
-z N Force foreground behavior. To be used in case Kermit doesn't automatically sense its foreground status. Equivalent to the SET BACKGROUND OFF command.

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:

Option Description
--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.

Plus several other IKSD-Only options.

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


On June 28, 2011, C-Kermit 9.0 was released with the Revised 3-Clause BSD License. This is a certified Open Source license, and it means that C-Kermit no longer needs to be licensed for commercial redistribution. Technical support for Kermit software is not available from Columbia University after June 30th, 2011.


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:


There you will also find Kermit software packages for other platforms: different Unix varieties, Windows, DOS, VMS, IBM mainframes, and many others: 20+ years' worth.


The manual for C-Kermit is:

  1. Frank da Cruz and Christine M. Gianone, Using C-Kermit, Second Edition, Digital Press / Butterworth-Heinemann, Woburn, MA, 1997, 622 pages, ISBN 1-55558-164-1. This is a printed book, now also available from Amazon.com as a Kindle E-Book. It covers C-Kermit 6.0.
      As of February 2016 Using C-Kermit can also be downloaded for free as a PDF file; CLICK HERE for details.

    Online Supplementary Material

  2. The C-Kermit 7.0 Supplement: https://kermitproject.org/ckermit70.html
  3. The C-Kermit 8.0 Supplement: https://kermitproject.org/ckermit80.html
  4. The C-Kermit 9.0 Supplement: https://kermitproject.org/ckermit90.html
  5. C-Kermit 10.0 update history: https://kermitproject.org/ckupdates.html

The C-Kermit home page is here:


Visit this page to learn about new versions, Beta tests, and other news; to read case studies and tutorials; to download source code, and for installation packages for different platforms. Also visit:

The Kermit script library and tutorial

The Kermit FAQ (Frequently Asked Questions about Kermit)

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

The Kermit security reference.

C-Kermit Telnet client documentation.

Case studies.

General C-Kermit Hints and Tips.

Unix C-Kermit Hints and Tips.

VMS C-Kermit Hints and Tips.

Unix C-Kermit Installation Instructions

VMS C-Kermit Installation Instructions

Technical support.

Kermit 95 tutorial (this document).

The Kermit newsgroup (unmoderated).

Kermit Home C-Kermit Home C-Kermit FAQ

C-Kermit 9.0 Unix Manual Page and Tutorial / 1 July 2011 / Updated: 2022/10/24