1SZ(1) General Commands Manual SZ(1)
2
6 sx, sb, sz - XMODEM, YMODEM, ZMODEM file send
7
9 sz [-+8abdefkLlNnopqTtuvyY] file ...
10 sb [-adfkqtuv] file ...
11 sx [-akqtuv] file
12 sz [-oqtv] -c COMMAND
13 sz [-oqtv] -i COMMAND
14 sz -TT
15
17 Sz uses the ZMODEM, YMODEM or XMODEM error correcting protocol to send
18 one or more files over a dial-in serial port to a variety of programs
19 running under PC-DOS, CP/M, Unix, VMS, and other operating systems.
20 While rz is smart enough to be called from cu(1), very few versions of
22 cu(1) are smart enough to allow sz to work properly. Unix flavors of
23 Professional-YAM are available for such dial-out application.
24 Sz sends one or more files with ZMODEM protocol.
27 ZMODEM greatly simplifies file transfers compared to XMODEM. In addi‐
29 tion to a friendly user interface, ZMODEM provides Personal Computer
30 and other users an efficient, accurate, and robust file transfer
31 method.
32 ZMODEM provides complete END-TO-END data integrity between application
34 programs. ZMODEM's 32 bit CRC catches errors that sneak into even the
35 most advanced networks.
36 Advanced file management features include AutoDownload (Automatic file
38 Download initiated without user intervention), Display of individual
39 and total file lengths and transmission time estimates, Crash Recovery,
40 selective file transfers, and preservation of exact file date and
41 length.
42 Output from another program may be piped to sz for transmission by
44 denoting standard input with "-":
45 ls -l | sz -
46 The program output is transmitted with the filename sPID.sz where PID
47 is the process ID of the sz program. If the environment variable ONAME
48 is set, that is used instead. In this case, the Unix command:
49 ls -l | ONAME=con sz -ay -
50 will send a "file" to the PC-DOS console display. The -y option
51 instructs the receiver to open the file for writing unconditionally.
52 The -a option causes the receiver to convert Unix newlines to PC-DOS
53 carriage returns and linefeeds.
54 Sb batch sends one or more files with YMODEM or ZMODEM protocol. The
57 initial ZMODEM initialization is not sent. When requested by the
58 receiver, sb supports YMODEM-g with "cbreak" tty mode, XON/XOFF flow
59 control, and interrupt character set to CAN (^X). YMODEM-g (Profes‐
60 sional-YAM g option) increases throughput over error free channels
61 (direct connection, X.PC, etc.) by not acknowledging each transmitted
62 sector.
63 On Unix systems, additional information about the file is transmitted.
65 If the receiving program uses this information, the transmitted file
66 length controls the exact number of bytes written to the output
67 dataset, and the modify time and file mode are set accordingly.
68 Sx sends a single file with XMODEM or XMODEM-1k protocol (sometimes
71 incorrectly called "ymodem"). The user must supply the file name to
72 both sending and receiving programs.
73 If sz is invoked with $SHELL set and if that variable contains the
75 string rsh , rbash or rksh (restricted shell), sz operates in
76 restricted mode. Restricted mode restricts pathnames to the current
77 directory and PUBDIR (usually /usr/spool/uucppublic) and/or subdirecto‐
78 ries thereof.
79 The fourth form sends a single COMMAND to a ZMODEM receiver for execu‐
82 tion. Sz exits with the COMMAND return value. If COMMAND includes
83 spaces or characters special to the shell, it must be quoted.
84 The fifth form sends a single COMMAND to a ZMODEM receiver for execu‐
87 tion. Sz exits as soon as the receiver has correctly received the com‐
88 mand, before it is executed.
89 The sixth form (sz -TT) attempts to output all 256 code combinations to
92 the terminal. In you are having difficulty sending files, this command
93 lets you see which character codes are being eaten by the operating
94 system.
95 If sz is invoked with stdout and stderr to different datasets, Verbose
98 is set to 2, causing frame by frame progress reports to stderr. This
99 may be disabled with the q option.
100 The meanings of the available options are:
102 -+, --append
104 Instruct the receiver to append transmitted data to an existing
105 file (ZMODEM only).
106 -2, --twostop
107 use two stop bits (if possible). Do not use this unless you know
108 what you are doing.
109 -8, --try-8k
110 Try to go up to 8KB blocksize. This is incompatible with stan‐
111 dard zmodem, but a common extension in the bbs world. (ZMODEM
112 only).
113 --start-8k
114 Start with 8KB blocksize. Like --try-8k.
115 -a, --ascii
116 Convert NL characters in the transmitted file to CR/LF. This is
117 done by the sender for XMODEM and YMODEM, by the receiver for
118 ZMODEM.
119 -b, --binary
120 (ZMODEM) Binary override: transfer file without any translation.
121 -B NUMBER, --bufsize NUMBER
122 Use a readbuffer of NUMBER bytes. Default is 16384, which should
123 be enough for most situations. If you have a slow machine or a
124 bad disk interface or suffer from other hardware problems you
125 might want to increase the buffersize. -1 or auto use a buffer
126 large enough to buffer the whole file. Be careful with this
127 option - things normally get worse, not better, if the machine
128 starts to swap.
129 Using this option turns of memory mapping of the input file.
131 This increases memory and CPU usage.
132 -c COMMAND, --command COMMAND
133 Send COMMAND to the receiver for execution, return with COM‐
134 MAND´s exit status.
135 -C N, --command-tries N
136 Retry to send command N times (default: 11).
137 -d, --dot-to-slash
138 Change all instances of "." to "/" in the transmitted pathname.
139 Thus, C.omenB0000 (which is unacceptable to MSDOS or CP/M) is
140 transmitted as C/omenB0000. If the resultant filename has more
141 than 8 characters in the stem, a "." is inserted to allow a
142 total of eleven.
143 This option enables the --full-path option.
145 --delay-startup N
146 Wait N seconds before doing anything.
147 -e, --escape
148 Escape all control characters; normally XON, XOFF, DLE, CR-@-CR,
149 and Ctrl-X are escaped.
150 Force the sender to rename the new file if a file with the same
151 name already exists.
152 -f, --full-path
153 Send Full pathname. Normally directory prefixes are stripped
154 from the transmitted filename.
155 This is also turned on with to --dot-to-slash option.
157 -h, --help
158 give help.
159 -i COMMAND, --immediate-command COMMAND
160 Send COMMAND to the receiver for execution, return immediately
161 upon the receiving program's successful reception of the com‐
162 mand.
163 -k, --1k
164 (XMODEM/YMODEM) Send files using 1024 byte blocks rather than
165 the default 128 byte blocks. 1024 byte packets speed file
166 transfers at high bit rates. (ZMODEM streams the data for the
167 best possible throughput.)
168 -L N, --packetlen N
169 Use ZMODEM sub-packets of length N. A larger N (32 <= N <=
170 1024) gives slightly higher throughput, a smaller N speeds error
171 recovery. The default is 128 below 300 baud, 256 above 300
172 baud, or 1024 above 2400 baud.
173 -m N, --min-bps N
174 Stop transmission if BPS-Rate (Bytes Per Second) falls below N
175 for a certain time (see --min-bps-time option).
176 -M N, --min-bps-time
177 Used together with --min-bps. Default is 120 (seconds).
178 -l N, --framelen N
179 Wait for the receiver to acknowledge correct data every N (32 <=
180 N <= 1024) characters. This may be used to avoid network over‐
181 run when XOFF flow control is lacking.
182 -n, --newer
183 (ZMODEM) Send each file if destination file does not exist.
184 Overwrite destination file if source file is newer than the des‐
185 tination file.
186 -N, --newer-or-longer
187 (ZMODEM) Send each file if destination file does not exist.
188 Overwrite destination file if source file is newer or longer
189 than the destination file.
190 -o, --16-bit-crc
191 (ZMODEM) Disable automatic selection of 32 bit CRC.
192 -O, --disable-timeouts
193 Disable read timeout handling. This makes lsz hang if the other
194 side doesn't send anything, but increases performance (not much)
195 and decreases system load (reduces number of system calls by
196 about 50 percent).
197 Use this option with care.
199 -p, --protect
200 (ZMODEM) Protect existing destination files by skipping transfer
201 if the destination file exists.
202 -q, --quiet
203 Quiet suppresses verbosity.
204 -R, --restricted
205 Restricted mode: restricts pathnames to the current directory
206 and PUBDIR (usually /usr/spool/uucppublic) and/or subdirectories
207 thereof.
208 -r, --resume
209 (ZMODEM) Resume interrupted file transfer. If the source file
210 is longer than the destination file, the transfer commences at
211 the offset in the source file that equals the length of the des‐
212 tination file.
213 -s HH:MM, --stop-at HH:MM
214 Stop transmission at HH hours, MM minutes. Another variant,
215 using +N instead of HH:MM, stops transmission in N seconds.
216 -S, --timesync
217 enable timesync protocol support. See timesync.doc for further
218 information.
219 This option is incompatible with standard zmodem. Use it with
221 care.
222 --syslog[=off]
223 turn syslogging on or off. the default is set at configure time.
224 This option is ignored if no syslog support is compiled in.
225 -t TIM, --timeout TIM
226 Change timeout to TIM tenths of seconds.
227 -T, --turbo
228 Do not escape certain characters (^P, ^P|0x80, telenet escape
229 sequence [CR + @]). This improves performance by about 1 percent
230 and shouldn't hurt in the normal case (but be careful - ^P might
231 be useful if connected through a terminal server).
232 --tcp Try to initiate a TCP/IP connection. lsz will ask the receiving
233 zmodem to open a TCP/IP connection. All handshaking (which
234 address / port to use) will be done by the zmodem programs.
235 You will normally not want to use this option as lrzsz is the
237 only zmodem which understands what to do (private extension).
238 You might want to use this option if the two programs are con‐
239 nected (stdin/out) over a slow or bad (not 8bit clean) network
240 connection.
241 Use of this option imposes a security risk, somebody else could
243 connect to the port in between. See SECURITY for details.
244 --tcp-client ADDRESS:PORT
245 Act as a tcp/ip client: Connect to the given port.
246 See --tcp-server for more information.
248 --tcp-server
250 Act as a server: Open a socket, print out what to do, wait for
251 connection.
252 You will normally not want to use this option as lrzsz is the
254 only zmodem which understands what to do (private extension).
255 You might want to use this if you have to use zmodem (for which
256 reason whatever), and cannot use the --tcp option of lsz (per‐
257 haps because your telnet doesn't allow to spawn a local program
258 with stdin/stdout connected to the remote side).
259 If you use this option you have to start lsz with the --tcp-
261 client ADDRESS:PORT option. lrz will print the address and port
262 on startup.
263 Use of this option imposes a security risk, somebody else could
265 connect to the port in between. See SECURITY for details.
266 -u Unlink the file after successful transmission.
268 -U, --unrestrict
269 Turn off restricted mode (this is not possible if running under
270 a restricted shell).
271 -w N, --windowsize N
272 Limit the transmit window size to N bytes (ZMODEM).
273 -v, --verbose
274 Verbose output to stderr. More v's generate more output.
275 -X, --xmodem
276 use XMODEM protocol.
277 -y, --overwrite
278 Instruct a ZMODEM receiving program to overwrite any existing
279 file with the same name.
280 -Y, --overwrite-or-skip
281 Instruct a ZMODEM receiving program to overwrite any existing
282 file with the same name, and to skip any source files that do
283 have a file with the same pathname on the destination system.
284 --ymodem
285 use ZMODEM protocol.
286 -Z, --zmodem
287 use ZMODEM protocol.
288
290 Restricted mode restricts pathnames to the current directory and PUBDIR
291 (usually /var/spool/uucppublic) and/or subdirectories thereof, and dis‐
292 ables remote command execution.
293 Restricted mode is entered if the R option is given or if lsz detects
295 that it runs under a restricted shell or if the environment variable
296 ZMODEM_RESTRICTED is found.
297 Restricted mode can be turned of with the U option if not running under
299 a restricted shell.
300 Use of the
303 --tcp-client or --tcp-server options imposes a security risk, as
304 somebody else could connect to the port before you do it, and
305 grab your data. If there's strong demand for a more secure mode
306 i might introduce some sort of password challenge.
307
311 ZNULLS may be used to specify the number of nulls to send before a
312 ZDATA frame.
313 SHELL lsz recognizes a restricted shell if this variable includes rsh
315 or rksh
316 ZMODEM_RESTRICTED
318 lrz enters restricted mode if the variable is set.
319 TMPDIR If this environment variable is set its content is used as the
321 directory to place in the answer file to a timesync request.
322 TMP Used instead of TMPDIR if TMPDIR is not set. If neither
323 TMPDIR nor TMP is set /tmp will be used.
324
326 ZMODEM File Transfer (Unix to DSZ/ZCOMM/Professional-YAM)
327 % sz -a *.c
328 This single command transfers all .c files in the current Unix direc‐
329 tory with conversion (-a) to end of line conventions appropriate to the
330 receiving environment. With ZMODEM AutoDownload enabled, Professional-
331 YAM and ZCOMM will automatically receive the files after performing a
332 security check.
333 % sz -Yan *.c *.h
335 Send only the .c and .h files that exist on both systems, and are newer
336 on the sending system than the corresponding version on the receiving
337 system, converting Unix to DOS text format.
338 $ sz -\Yan file1.c file2.c file3.c foo.h baz.h ®(for VMS)
339 ZMODEM Command Download (Unix to Professional-YAM)
341 cpszall:all
342 sz -c "c:;cd /yam/dist"
343 sz -ya $(YD)/*.me
344 sz -yqb y*.exe
345 sz -c "cd /yam"
346 sz -i "!insms"
347 This Makefile fragment uses sz to issue commands to Professional-YAM to
348 change current disk and directory. Next, sz transfers the .me files
349 from the $YD directory, commanding the receiver to overwrite the old
350 files and to convert from Unix end of line conventions to PC-DOS con‐
351 ventions. The third line transfers some .exe files. The fourth and
352 fifth lines command Pro-YAM to change directory and execute a PC-DOS
353 batch file insms . Since the batch file takes considerable time, the
354 -i form is used to allow sz to exit immediately.
355 XMODEM File Transfer (Unix to Crosstalk)
357 % sx -a foo.c
358 ESC
359 rx foo.c
360 The above three commands transfer a single file from Unix to a PC and
361 Crosstalk with sz translating Unix newlines to DOS CR/LF. This combi‐
362 nation is much slower and far less reliable than ZMODEM.
363
365 "Caught signal 99" indicates the program was not properly compiled,
366 refer to "bibi(99)" in rbsb.c for details.
367
369 rz(omen), ZMODEM.DOC, YMODEM.DOC, Professional-YAM, crc(omen),
370 sq(omen), todos(omen), tocpm(omen), tomac(omen), yam(omen)
371 Compile time options required for various operating systems are
373 described in the source file.
374
376 The VMS version does not support wild cards. Because of VMS DCL, upper
377 case option letters muse be represented by \ proceeding the letter.
378 The current VMS version does not support XMODEM, XMODEM-1k, or YMODEM.
380 VMS C Standard I/O and RMS may interact to modify the file contents.
382
384 32 bit CRC code courtesy Gary S. Brown.
385 sz.c, crctab.c, rbsb.c, zm.c, zmodem.h Unix source files
387 sz.c, crctab.c, vrzsz.c, zm.c, zmodem.h, vmodem.h, vvmodem.c, VMS
389 source files.
390 /tmp/szlog stores debugging output (sz -vv) (szlog on VMS).
392
394 The command "sz -T file" exercises the Attn sequence error recovery by
395 commanding errors with unterminated packets. The receiving program
396 should complain five times about binary data packets being too long.
397 Each time sz is interrupted, it should send a ZDATA header followed by
398 another defective packet. If the receiver does not detect five long
399 data packets, the Attn sequence is not interrupting the sender, and the
400 Myattn string in sz.c must be modified.
401 After 5 packets, sz stops the "transfer" and prints the total number of
403 characters "sent" (Tcount). The difference between Tcount and 5120
404 represents the number of characters stored in various buffers when the
405 Attn sequence is generated.
406
408 Calling sz from most versions of cu(1) doesn't work because cu's
409 receive process fights sz for characters from the modem.
410 On at least one BSD system, sz would hang or exit when it got within a
412 few kilobytes of the end of file. Using the "-w 8192" flag fixed the
413 problem. The real cause is unknown, perhaps a bug in the kernel TTY
414 output routines.
415 Programs that do not properly implement the specified file transfer
417 protocol may cause sz to "hang" the port for a minute or two. This
418 problem is corrected by using ZCOMM, Pro-YAM, or other program with a
419 correct implementation of the specified protocol.
420 Many programs claiming to support YMODEM only support XMODEM with 1k
422 blocks, and they often don't get that quite right.
423 XMODEM transfers add up to 127 garbage bytes per file. XMODEM-1k and
425 YMODEM-1k transfers use 128 byte blocks to avoid extra padding.
426 YMODEM programs use the file length transmitted at the beginning of the
428 transfer to prune the file to the correct length; this may cause prob‐
429 lems with source files that grow during the course of the transfer.
430 This problem does not pertain to ZMODEM transfers, which preserve the
431 exact file length unconditionally.
432 Most ZMODEM options are merely passed to the receiving program; some do
434 not implement all these options.
435 Circular buffering and a ZMODEM sliding window should be used when
437 input is from pipes instead of acknowledging frames each 1024 bytes.
438 If no files can be opened, sz sends a ZMODEM command to echo a suitable
439 complaint; perhaps it should check for the presence of at least one
440 accessible file before getting hot and bothered. The test mode leaves
441 a zero length file on the receiving system.
442 A few high speed modems have a firmware bug that drops characters when
444 the direction of high speed transmission is reversed. The environment
445 variable ZNULLS may be used to specify the number of nulls to send
446 before a ZDATA frame. Values of 101 for a 4.77 MHz PC and 124 for an
447 AT are typical.
448lrzsz-0.12b 2.6.1996 SZ(1)