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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 addi‐
       tion 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	initialization	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).  YMODEM-g (Profes‐
       sional-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 accordingly.

       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 pathnames to the current
       directory and PUBDIR (usually /usr/spool/uucppublic) and/or subdirecto‐
       ries thereof.

       The  fourth form sends a single COMMAND to a ZMODEM receiver for execu‐
       tion.  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 execu‐
       tion.  Sz exits as soon as the receiver has correctly received the com‐
       mand, 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, causing 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	 stan‐
	      dard  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 COM‐
	      MAND´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) characters.  This may be used to avoid network over‐
	      run 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 des‐
	      tination 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 des‐
	      tination 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  con‐
	      nected  (stdin/out)  over a slow or bad (not 8bit clean) network
	      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 (per‐
	      haps because your telnet doesn't allow to spawn a local  program
	      with stdin/stdout 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 dis‐
       ables remote command execution.

       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 direc‐
       tory 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 ®(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  con‐
       ventions.   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 immediately.

       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 combi‐
       nation 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 letters 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	 prob‐
       lems  with  source  files  that grow during the course of the transfer.
       This problem does not pertain to ZMODEM transfers, which	 preserve  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 specify 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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