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 (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 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.