kermit r[ddziftlbp] [line] [baud] [parity]
kermit s[ddziftlbp] [line] [baud] [parity] file~...
The arguments to kermit are a set of flags (no spaces between the flags), three optional args (which, if included, must be in the same order as the flags which indicate their presence), and, if this is a Send operation, a list of one or more files. (It is similar in some way to the tar command structure).
Kermit has three modes: Connect, Send, and Receive. The first is for a virtual terminal connection, the other two for file transfer. These modes are specified by the first flag, which should be c,~s, or r, respectively. Exactly one mode must be specified.
The d flag (debug) makes kermit a bit more verbose. The states kermit goes through are printed along with other traces of it's operation. A second d flag will cause kermit to give an even more detailed trace.
The z flag creates a file called PACKET.LOG in the current directory. In it is stored a detailed account of the packet transactions which occur during a Send or Receive operation.
The i flag (image) allows slightly more efficient file transfer between Unix machines. Normally (on Kermits defined to run on Unix systems) newline is mapped to CRLF on output, CR's are discarded on input, and bytes are masked to 7 bits. If this is set, no mapping is done on newlines, and all eight bits of each byte are sent or received. This is the default for non-Unix kermits.
The l flag (line) specifies the tty line that kermit should use to communicate with the other machine. This is specified as a regular filename, like "/dev/ttyh1". If no l option is specified, standard input is used and kermit assumes it is running on the remote host (ie. NOT the machine to which your terminal is attached).
The b flag (baud) sets the baud rate on the line specified by the l flag. No changes are made if the b flag is not used. Legal speeds are: 110, 150, 300, 1200, 2400, 4800, 9600. Note that this version of kermit supports this option on Unix systems only.
The e flag (escape) allows the user to set the first character of the two character escape sequence for Connect mode. When the escape character (default, '^') is typed, kermit will hold it and wait for the next character. If the next character is c or C, kermit will close the connection with the remote host. If the second character is the same as the escape character, the escape character itself is passed. Any character other than these two results in a bell being sent to the user's terminal and no characters passed to the remote host. All other typed characters are passed through unchanged.
The p flag (parity) allows parity to be set on outgoing packets and stripped on incoming ones. This is useful for communicating with IBM hosts or over networks, such as TELENET, that usurp the parity bit. The possible values for parity are mark, space, even, odd or none (the default).
The t flag (turnaround) tells kermit while in protocol mode (sending or receiving) to wait for a turnaround character (XON) from the other host after receiving every packet. This is necessary to run kermit with a half duplex host such as an IBM mainframe.
The h flag (half duplex) makes kermit echo locally any characters typed in connect mode. This is also necessary to communicate with a half duplex system like an IBM 370.
The file arguments are only meaningful to a Send kermit. The Receiving kermit will attempt to store the file with the same name that was used to send it. Unix kermits normally convert outgoing file names to uppercase and incoming ones to lower case. The f flag supresses this filename conversion. If a filename contains a slash (/) all outgoing kermits will strip off the leading part of the name through the last slash. Receiving kermits, of course, store incoming files in the current directory.
We want to connect to "unixb", then transfer "file1" to that machine.
We type: kermit clb /dev/tty03 1200
Kermit answers: Kermit: connected...
Now we dial the remote machine and connect the modem. Anything typed on the terminal will be sent to the remote machine and any output from that machine will be displayed on our terminal. We hit RETURN, get a "login:" prompt and login.
Now we need to start a kermit on the remote machine so that we can send the file over. First we start up the remote, (in this case receiving) kermit, then the local, (sending) one. Remember that we are talking to unixb right now.
We type: kermit r
(there is now a Receive kermit on unixb)
We type ^ (the escape character) and then c to kill the local (Connecting) kermit.
Kermit answers: Kermit: disconnected.
We type: kermit slb /dev/tty03 1200 file1
Kermit answers: Sending file1 as FILE1
When the transmission is finished, kermit will type either "Send complete", or "Send failed.", depending on the success of the transfer. If we now wanted to transfer a file from unixb (remote) to unixa (local), we would use these commands:
kermit clb /dev/tty03 1200
~~(connected to unixb)
kermit s file9
^c (up-arrow c not control-c)
~~(talking to unixa again)
kermit rl /dev/tty03 1200
After all the transfers were done, we should connect again, log off of unixb, kill the Connect kermit and hang up the phone.
The KERMIT Protocol uses only printing ASCII characters, Ctrl-A, and CRLF. Ctrl-S/Ctrl-Q flow control can be used "underneath" the Kermit protocol (TANDEM line discipline on Berkeley Unix).
Since BREAK is not an ASCII character, kermit cannot send a BREAK to the remote machine. On some systems, a BREAK will be read as a NUL. (In any case, UNIX kermits attempt to send a BREAK through the TIOC?BRK 'ioctl' of the tty driver).
This kermit does have timeouts when run under Unix, so the protocol is stable when communicating with "dumb" kermits (that don't have timeouts).
Details on other implementations and on the protocol itself is given in the Kermit Users Guide, and the Kermit Protocol Handbook. Two articles explaining kermit's design, specifications and implementaion can be found in BYTE, June and July, 1984, Vol. 9, #6 and #7. The authors are Frank da Cruz and Bill Catchings.
Kermit Users Guide, Fourth Edition (4 May 83), Frank da Cruz, Daphne Tzoar, Bill Catchings
Kermit Protocol Manual, Protocol Version 3 (29 April 83), Frank da Cruz, Bill Catchings
Both of the above documents are from the Columbia University Center for Computing Activities, New York, New York, 10027.
This implementation does not send or process error-message packets.
Repeat-count prefixing and eighth-bit quoting are not implemented.
KERMIT kernel by Bill Catchings, Columbia University Center for Computing Activities
KERMIT-Unix adaptation by Chris Maio and Bob Cattani, Columbia University Computer Science Dept.
Local mods for v6, System III, and System V by Walter Underwood. Includes bug fixes from Jim Guyton at RAND-Unix.
kermit was named after Kermit the Frog, the star of The Muppet Show; the name is used with permission of Henson Associates Inc.