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SZ(1)											    SZ(1)

NAME
       sx, sb, sz - XMODEM, YMODEM, ZMODEM file send

SYNOPSIS
       sz [-+8abdefkLlNnopqTtuvyY] file ...
       sb [-adfkqtuv] file ...
       sx [-akqtuv] file
       sz [-oqtv] -c COMMAND
       sz [-oqtv] -i COMMAND
       sz -TT

DESCRIPTION
       Sz  uses  the ZMODEM, YMODEM or XMODEM error correcting protocol to send one or more files
       over a dial-in serial port to a variety of programs running under PC-DOS, CP/M, Unix, VMS,
       and other operating systems.

       While  rz  is  smart  enough to be called from cu(1), very few versions of cu(1) are smart
       enough to allow sz to work properly.  Unix flavors of Professional-YAM are  available  for
       such dial-out application.

       Sz sends one or more files with ZMODEM protocol.

       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.

       Advanced file management features include AutoDownload (Automatic file Download	initiated
       without	user intervention), Display of individual and total file lengths and transmission
       time estimates, Crash Recovery, selective file transfers, and preservation of  exact  file
       date and length.

       Output from another program may be piped to sz for transmission 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 Unix 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 convert
       Unix newlines to PC-DOS carriage returns and linefeeds.

       Sb batch sends one or more files with YMODEM or ZMODEM protocol.  The initial ZMODEM  ini-
       tialization  is	not  sent.   When  requested  by  the receiver, sb supports YMODEM-g with
       "cbreak" tty mode, XON/XOFF flow control, and interrupt character set to CAN  (^X).   YMO-
       DEM-g  (Professional-YAM  g  option) increases throughput over error free channels (direct
       connection, X.PC, etc.)	by not acknowledging each transmitted sector.

       On Unix systems, additional information about the file is transmitted.  If  the	receiving
       program	uses  this  information, the transmitted file length controls the exact number of
       bytes written to the output dataset, and the modify time and file  mode	are  set  accord-
       ingly.

       Sx  sends  a  single  file with XMODEM or XMODEM-1k protocol (sometimes incorrectly called
       "ymodem").  The user must supply the file name to both sending and receiving programs.

       If sz is invoked with $SHELL set and iff that variable contains the string rsh , rbash  or
       rksh  (restricted shell), sz operates in restricted mode.  Restricted mode restricts path-
       names to the current directory and PUBDIR (usually /usr/spool/uucppublic) and/or subdirec-
       tories thereof.

       The  fourth form sends a single COMMAND to a ZMODEM receiver for execution.  Sz exits with
       the COMMAND return value.  If COMMAND includes spaces or characters special to the  shell,
       it must be quoted.

       The  fifth  form  sends	a single COMMAND to a ZMODEM receiver for execution.  Sz exits as
       soon as the receiver has correctly received the command, before it is executed.

       The sixth form (sz -TT) attempts to output all 256 code combinations to the terminal.   In
       you  are  having difficulty sending files, this command lets you see which character codes
       are being eaten by the operating system.

       If sz is invoked with stdout and stderr to different datasets, Verbose is set to 2,  caus-
       ing frame by frame progress reports to stderr.  This may be disabled with the q option.

       The meanings of the available options are:

       -+, --append
	      Instruct the receiver to append transmitted data to an existing file (ZMODEM only).
       -2, --twostop
	      use  two	stop  bits  (if  possible).  Do not use this unless you know what you are
	      doing.
       -8, --try-8k
	      Try to go up to 8KB blocksize. This is incompatible with	standard  zmodem,  but	a
	      common extension in the bbs world. (ZMODEM only).
       --start-8k
	      Start with 8KB blocksize. Like --try-8k.
       -a, --ascii
	      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
	      (ZMODEM) Binary override: transfer file without any translation.
       -B NUMBER, --bufsize NUMBER
	      Use a readbuffer of NUMBER bytes. Default ist 16384, which  should  be  enough  for
	      most  situations. If you have a slow machine or a bad disk interface or suffer from
	      other hardware problems you might want to increase the buffersize.  -1 or auto  use
	      a  buffer  large	enough	to  buffer  the whole file. Be careful with this option -
	      things normally get worse, not better, if the machine starts to swap.

	      Using this option turns of memory mapping of the input file. This increases  memory
	      and cpu usage.
       -c COMMAND, --command COMMAND
	      Send COMMAND to the receiver for execution, return with COMMAND's exit status.
       -C N, --command-tries N
	      Retry to send command N times (default: 11).
       -d, --dot-to-slash
	      Change  all instances of "." to "/" in the transmitted pathname.	Thus, C.omenB0000
	      (which is unacceptable to MSDOS 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.

	      This option enables the --full-path option.
       --delay-startup N
	      Wait N seconds before doing anything.
       -e, --escape
	      Escape all control characters; normally XON, XOFF, DLE,  CR-@-CR,  and  Ctrl-X  are
	      escaped.
       Force the sender to rename the new file if a file with the same
	      name already exists.
       -f, --full-path
	      Send  Full pathname.  Normally directory prefixes are stripped from the transmitted
	      filename.

	      This is also turned on with to --dot-to-slash option.
       -h, --help
	      give help.
       -i COMMAND, --immediate-command COMMAND
	      Send COMMAND to the receiver for execution, return immediately upon  the	receiving
	      program's successful recption of the command.
       -k, --1k
	      (XMODEM/YMODEM)  Send files using 1024 byte blocks rather than the default 128 byte
	      blocks.  1024 byte packets speed file transfers at high bit rates.  (ZMODEM streams
	      the data for the best possible throughput.)
       -L N, --packetlen N
	      Use  ZMODEM  sub-packets	of length N.  A larger N (32 <= N <= 1024) gives slightly
	      higher throughput, a smaller N speeds error recovery.  The default is 128 below 300
	      baud, 256 above 300 baud, or 1024 above 2400 baud.
       -m N, --min-bps N
	      Stop  transmission  if BPS-Rate (Bytes Per Second) falls below N for a certain time
	      (see --min-bps-time option).
       -M N, --min-bps-time
	      Used together with --min-bps. Default is 120 (seconds).
       -l N, --framelen N
	      Wait for the receiver to acknowledge correct data every N (32 <= N <= 1024) charac-
	      ters.  This may be used to avoid network overrun when XOFF flow control is lacking.
       -n, --newer
	      (ZMODEM)	Send each file if destination file does not exist.  Overwrite destination
	      file if source file is newer than the destination file.
       -N, --newer-or-longer
	      (ZMODEM) Send each file if destination file does not exist.  Overwrite  destination
	      file if source file is newer or longer than the destination file.
       -o, --16-bit-crc
	      (ZMODEM) Disable automatic selection of 32 bit CRC.
       -O, --disable-timeouts
	      Disable  read  timeout handling. This makes lsz hang if the other side doesn't send
	      anything, but increases performance (not much) and decreases system  load  (reduces
	      number of system calls by about 50 percent).

	      Use this option with care.
       -p, --protect
	      (ZMODEM) Protect existing destination files by skipping transfer if the destination
	      file exists.
       -q, --quiet
	      Quiet suppresses verbosity.
       -R, --restricted
	      Restricted mode: restricts pathnames to the current directory and  PUBDIR  (usually
	      /usr/spool/uucppublic) and/or subdirectories thereof.
       -r, --resume
	      (ZMODEM)	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.
       -s HH:MM, --stop-at HH:MM
	      Stop  transmission  at  HH  hours, MM minutes. Another variant, using +N instead of
	      HH:MM, stops transmission in N seconds.
       -S, --timesync
	      enable timesync protocol support. See timesync.doc for further information.

	      This option is incompatible with standard zmodem. Use it with care.
       --syslog[=off]
	      turn syslogging on or off. the default is set at configure time.	 This  option  is
	      ignored if no syslog support is compiled in.
       -t TIM, --timeout TIM
	      Change timeout to TIM tenths of seconds.
       -T, --turbo
	      Do  not  escape certain characters (^P, ^P|0x80, telenet escape sequence [CR + @]).
	      This improves performance by about 1 percent and shouldn't hurt in the normal  case
	      (but be careful - ^P might be useful if connected through a terminal server).
       --tcp  Try  to  initiate  a TCP/IP connection. lsz will ask the receiving zmodem to open a
	      TCP/IP connection. All handshaking (which address / port to use) will  be  done  by
	      the zmodem programs.

	      You  will  normally  not	want to use this option as lrzsz is the only zmodem which
	      understands what to do (private extension). You might want to use  this  option  if
	      the two programs are connected (stdin/out) over a slow or bad (not 8bit clean) net-
	      work connection.

	      Use of this option imposes a security risk, somebody else could connect to the port
	      in between. See SECURITY for details.
       --tcp-client ADDRESS:PORT
	      Act as a tcp/ip client: Connect to the given port.

	      See --tcp-server for more information.

       --tcp-server
	      Act as a server: Open a socket, print out what to do, wait for connection.

	      You  will  normally  not	want to use this option as lrzsz is the only zmodem which
	      understands what to do (private extension). You might want to use this if you  have
	      to  use  zmodem (for which reason whatever), and cannot use the --tcp option of lsz
	      (perhaps because your telnet doesn't allow to spawn a local program with stdin/std-
	      out connected to the remote side).

	      If  you  use  this  option you have to start lsz with the --tcp-client ADDRESS:PORT
	      option.  lrz will print the address and port on startup.

	      Use of this option imposes a security risk, somebody else could connect to the port
	      in between. See SECURITY for details.

       -u     Unlink the file after successful transmission.
       -U, --unrestrict
	      Turn  off  restricted  mode  (this  is  not  possible if running under a restricted
	      shell).
       -w N, --windowsize N
	      Limit the transmit window size to N bytes (ZMODEM).
       -v, --verbose
	      Verbose output to stderr. More v's generate more output.
       -X, --xmodem
	      use XMODEM protocol.
       -y, --overwrite
	      Instruct a ZMODEM receiving program to overwrite any existing file  with	the  same
	      name.
       -Y, --overwrite-or-skip
	      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.
       --ymodem
	      use ZMODEM protocol.
       -Z, --zmodem
	      use ZMODEM protocol.

SECURITY
       Restricted  mode  restricts  pathnames  to  the	current  directory  and  PUBDIR  (usually
       /var/spool/uucppublic) and/or subdirectories thereof, and disables remote  command  execu-
       tion.

       Restricted mode is entered if the R option is given or if lsz detects that it runs under a
       restricted shell or if the environment variable ZMODEM_RESTRICTED is found.

       Restricted mode can be turned of with the U option  if  not  running  under  a  restricted
       shell.

       Use of the
	      --tcp-client  or	--tcp-server  options  imposes	a security risk, as somebody else
	      could connect to the port before you do it, and grab your data. If  there's  strong
	      demand for a more secure mode i might introduce some sort of password challenge.

ENVIRONMENT
       ZNULLS may be used to specify the number of nulls to send before a ZDATA frame.

       SHELL  lsz recognizes a restricted shell if this variable includes rsh or rksh

       ZMODEM_RESTRICTED
	      lrz enters restricted mode if the variable is set.

       TMPDIR If  this	environment variable is set its content is used as the directory to place
	      in the answer file to a timesync request.  TMP Used instead of TMPDIR if TMPDIR  is
	      not set. If neither TMPDIR nor TMP is set /tmp will be used.

EXAMPLES
       ZMODEM File Transfer (Unix to DSZ/ZCOMM/Professional-YAM)
       % sz -a *.c
       This  single  command transfers all .c files in the current Unix directory with conversion
       (-a) to end of line conventions appropriate to the  receiving  environment.   With  ZMODEM
       AutoDownload  enabled,  Professional-YAM   and  ZCOMM will automatically recieve the files
       after performing a security check.

       % 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 Unix to DOS text
       format.
       $ sz -\Yan file1.c file2.c file3.c foo.h baz.h (R)(for VMS)

       ZMODEM Command Download (Unix to Professional-YAM)
	cpszall:all
	   sz -c "c:;cd /yam/dist"
	   sz -ya $(YD)/*.me
	   sz -yqb y*.exe
	   sz -c "cd /yam"
	   sz -i "!insms"
       This Makefile fragment uses sz to issue commands to  Professional-YAM  to  change  current
       disk  and  directory.  Next, sz transfers the .me files from the $YD directory, commanding
       the receiver to overwrite the old files and to convert from Unix end of	line  conventions
       to  PC-DOS  conventions.   The third line transfers some .exe files.  The fourth and fifth
       lines command Pro-YAM to change directory and execute a PC-DOS batch file insms	.   Since
       the  batch  file  takes considerable time, the -i form is used to allow sz to exit immedi-
       ately.

       XMODEM File Transfer (Unix to Crosstalk)
       % sx -a foo.c
       ESC
       rx foo.c
       The above three commands transfer a single file from Unix to a PC and  Crosstalk  with  sz
       translating  Unix  newlines  to	DOS  CR/LF.  This combination is much slower and far less
       reliable than ZMODEM.

ERROR MESSAGES
       "Caught signal 99" indicates the program was not properly compiled, refer to "bibi(99)" in
       rbsb.c for details.

SEE ALSO
       rz(omen),  ZMODEM.DOC,  YMODEM.DOC,  Professional-YAM,  crc(omen),  sq(omen), todos(omen),
       tocpm(omen), tomac(omen), yam(omen)

       Compile time options required for various operating systems are described  in  the  source
       file.

VMS VERSION
       The  VMS  version does not support wild cards.  Because of VMS DCL, upper case option let-
       ters muse be represented by \ proceding the letter.

       The current VMS version does not support XMODEM, XMODEM-1k, or YMODEM.

       VMS C Standard I/O and RMS may interact to modify the file contents.

FILES
       32 bit CRC code courtesy Gary S. Brown.

       sz.c, crctab.c, rbsb.c, zm.c, zmodem.h Unix source files

       sz.c, crctab.c, vrzsz.c, zm.c, zmodem.h, vmodem.h, vvmodem.c, VMS source files.

       /tmp/szlog stores debugging output (sz -vv) (szlog on VMS).

TESTING FEATURE
       The command "sz -T file" exercises the Attn sequence error recovery by  commanding  errors
       with  unterminated packets.  The receiving program should complain five times about binary
       data packets being too long.  Each time sz is interrupted, it should send a  ZDATA  header
       followed  by  another  defective  packet.   If the receiver does not detect five long data
       packets, the Attn sequence is not interrupting the sender, and the Myattn string  in  sz.c
       must be modified.

       After  5 packets, sz stops the "transfer" and prints the total number of characters "sent"
       (Tcount).  The difference between Tcount and 5120  represents  the  number  of  characters
       stored in various buffers when the Attn sequence is generated.

BUGS
       Calling sz from most versions of cu(1) doesn't work because cu's receive process fights sz
       for characters from the modem.

       On at least one BSD system, sz would hang or exit when it got within a  few  kilobytes  of
       the  end of file.  Using the "-w 8192" flag fixed the problem.  The real cause is unknown,
       perhaps a bug in the kernel TTY output routines.

       Programs that do not properly implement the specified file transfer protocol may cause  sz
       to  "hang"  the	port for a minute or two.  This problem is corrected by using ZCOMM, Pro-
       YAM, or other program with a correct implementation of the specified protocol.

       Many programs claiming to support YMODEM only support XMODEM  with  1k  blocks,	and  they
       often don't get that quite right.

       XMODEM  transfers add up to 127 garbage bytes per file.	XMODEM-1k and YMODEM-1k transfers
       use 128 byte blocks to avoid extra padding.

       YMODEM programs use the file length transmitted at the beginning of the transfer to  prune
       the file to the correct length; this may cause problems with source files that grow during
       the course of the transfer.  This problem does not pertain to ZMODEM transfers, which pre-
       serve the exact file length unconditionally.

       Most  ZMODEM options are merely passed to the receiving program; some do not implement all
       these options.

       Circular buffering and a ZMODEM sliding window should be used when  input  is  from  pipes
       instead	of  acknowledging  frames each 1024 bytes.  If no files can be opened, sz sends a
       ZMODEM command to echo a suitable complaint; perhaps it should check for the  presence  of
       at least one accessible file before getting hot and bothered.  The test mode leaves a zero
       length file on the receiving system.

       A few high speed modems have a firmware bug that drops characters when  the  direction  of
       high speed transmissson is reversed.  The environment variable ZNULLS may be used to spec-
       ify the number of nulls to send before a ZDATA frame.  Values of 101 for a 4.77 mHz PC and
       124 for an AT are typical.

lrzsz-0.12b				     2.6.1996					    SZ(1)
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