Provided by: lrzsz_0.12.21-5_amd64 bug

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
       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 (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
       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
       subdirectories 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,
       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 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.
       -E, --rename
              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 reception 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 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)
              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
              (perhaps  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  disables  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 directory  with  conversion
       (-a)  to  end  of  line conventions appropriate to the receiving environment.  With ZMODEM
       AutoDownload enabled, Professional-YAM  and ZCOMM will  automatically  receive  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 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
       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 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
       letters must be represented by \ preceding 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
       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 transmission 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.