NAME
sz - send a file using the zmodem protocol
SYNOPSIS
sz [-LNbdefnopqruvy+] [-ci command] [-Ll n] [-t timeout]
OPTIONS
-L Use n-byte packets
-N Overwrite if source is newer/longer
-b Binary file
-c Send command for execution
-d Convert dot to slash in names
-e Escape for all control characters
-f Send full path name
-i Send command and return immediately
-l Flow control every n packets
-n Overwrite destination if source is newer
-o Use old (16-bit) checksum
-p Protect file if it already exists
-q Quiet; opposite of verbose
-r Resume interrupt file transfer
-t Set timeout in tenths of a second
-u Unlink file after successful transmission
-v Verbose; opposite of quiet
-y Yes, clobber existing files
-+ Append to an existing file
EXAMPLES
sz file </dev/tty01 >/dev/tty01
# Send file
DESCRIPTION
XMODEM, YMODEM, and ZMODEM are a family of protocols that
are widely used is the MS-DOS world for transferring
information reliably from one computer to another. In all
of these protocols, a series of bytes are sent from one com-
puter to the other, and then an acknowledgement is sent back
to confirm correct reception. Checksums are used to detect
errors so that transmission is reliable even in the face of
noisy telephone lines. Sz is a program that sends a file
sent from another computer using the zmodem protocol. The
file can be received using rz.
Sz uses the ZMODEM error correcting protocol to send one or
more files over a dial-in serial port to a variety of pro-
grams running under MINIX 3, UNIX, MS-DOS, CP/M, VMS, and
other operating systems. It is the successor to XMODEM and
YMODEM.
ZMODEM greatly simplifies file transfers compared to XMODEM.
In addition to a friendly user interface, ZMODEM provides
Personal Computer and other users an efficient, accurate,
and robust file transfer method.
ZMODEM provides complete end-to-end data integrity between
application programs. ZMODEM's 32 bit CRC catches errors
that sneak into even the most advanced networks.
Output from another program may be piped to sz for transmis-
sion by denoting standard input with -:
" "ls -l | sz -
The program output is transmitted with the filename sPID.sz
where PID is the process ID of the sz program. If the
environment variable ONAME is set, that is used instead. In
this case, the command:
" "ls -l | ONAME=con sz -ay -
will send a 'file' to the PC-DOS console display. The -y
option instructs the receiver to open the file for writing
unconditionally. The -a option causes the receiver to con-
vert UNIX newlines to PC-DOS carriage returns and linefeeds.
On UNIX systems, additional information about the file is
transmitted. If the receiving program uses this informa-
tion, the transmitted file length controls the exact number
of bytes written to the output dataset, and the modify time
and file mode are set accordingly.
If sz is invoked with $SHELL set and if that variable con-
tains the string rsh or rksh (restricted shell), sz operates
in restricted mode. Restricted mode restricts pathnames to
the current directory and PUBDIR (usually
/usr/spool/uucppublic) and/or subdirectories thereof.
The options and flags available are:
-+
Instruct the receiver to append transmitted data to an
existing file.
-a
Convert NL characters in the transmitted file to CR/LF.
This is done by the sender for XMODEM and YMODEM, by the
receiver for ZMODEM.
-b
Binary override: transfer file without any translation.
-c
Send COMMAND (follows c) to the receiver for execution,
return with COMMAND's exit status.
-d
Change all instances of '.' to '/' in the transmitted
pathname. Thus, C.omenB0000 (which is unacceptable to
MS-DOS or CP/M) is transmitted as C/omenB0000. If the
resultant filename has more than 8 characters in the stem,
a '.' is inserted to allow a total of eleven.
-e
Escape all control characters; normally XON, XOFF, DLE,
CR-@-CR, and Ctrl-X are escaped.
-f
Send Full pathname. Normally directory prefixes are
stripped from the transmitted filename.
-i
Send COMMAND (follows i) to the receiver for execution,
return Immediately upon the receiving program's successful
reception of the command.
-L
Use ZMODEM sub-packets of length n (follows L). A larger n
(32 <= n <= 1024) gives slightly higher throughput, a
smaller one speeds error recovery. The default is 128
below 300 baud, 256 above 300 baud, or 1024 above 2400
baud.
-l
Wait for the receiver to acknowledge correct data every n
(32 <= n <= 1024) characters. This may be used to avoid
network overrun when XOFF flow control is lacking.
-n
Send each file if destination file does not exist.
Overwrite destination file if source file is newer than
the destination file.
-N
Send each file if destination file does not exist.
Overwrite destination file if source file is newer or
longer than the destination file.
-o
Disable automatic selection of 32 bit CRC.
-p
Protect existing destination files by skipping transfer if
the destination file exists.
-q
Quiet suppresses verbosity.
-r
Resume interrupted file transfer. If the source file is
longer than the destination file, the transfer commences
at the offset in the source file that equals the length of
the destination file.
-t
Change timeout. The timeout, in tenths of seconds, fol-
lows, the -t flag.
-u
Unlink the file after successful transmission.
-w
Limit the transmit window size to n bytes (n follows
(enw).
-v
Verbose causes a list of file names to be appended to
/tmp/szlog.
-y
Instruct a ZMODEM receiving program to overwrite any
existing file with the same name.
-Y
Instruct a ZMODEM receiving program to overwrite any
existing file with the same name, and to skip any source
files that do have a file with the same pathname on the
destination system.
Examples
Below are some examples of the use of sz.
" "sz -a *.c
This single command transfers all .c files in the current
directory with conversion (-a) to end-of-line conventions
appropriate to the receiving environment.
" "sz -Yan *.c *.h
Send only the .c and .h files that exist on both systems,
and are newer on the sending system than the corresponding
version on the receiving system, converting MINIX 3 to MS-
DOS text format.
SEE ALSO
rz(1), term(1).