1PV(1) User Manuals PV(1)
2
6 pv - monitor the progress of data through a pipe
7
9 pv [OPTION] [FILE]...
10 pv [-h|-V]
11
15 pv shows the progress of data through a pipeline by giving information
16 such as time elapsed, percentage completed (with progress bar), current
17 throughput rate, total data transferred, and ETA.
18 To use it, insert it in a pipeline between two processes, with the ap‐
20 propriate options. Its standard input will be passed through to its
21 standard output and progress will be shown on standard error.
22 pv will copy each supplied FILE in turn to standard output (- means
24 standard input), or if no FILEs are specified just standard input is
25 copied. This is the same behaviour as cat(1).
26 A simple example to watch how quickly a file is transferred using
28 nc(1):
29 pv file | nc -w 1 somewhere.com 3000
31 A similar example, transferring a file from another process and passing
33 the expected size to pv:
34 cat file | pv -s 12345 | nc -w 1 somewhere.com 3000
36 A more complicated example using numeric output to feed into the dia‐
38 log(1) program for a full-screen progress display:
39 (tar cf - . \
41 | pv -n -s $(du -sb . | awk '{print $1}') \
42 | gzip -9 > out.tgz) 2>&1 \
43 | dialog --gauge 'Progress' 7 70
44 Taking an image of a disk, skipping errors:
46 pv -EE /dev/your/disk/device > disk-image.img
48 Writing an image back to a disk:
50 pv disk-image.img > /dev/your/disk/device
52 Zeroing a disk:
54 pv < /dev/zero > /dev/your/disk/device
56 Note that if the input size cannot be calculated, and the output is a
58 block device, then the size of the block device will be used and pv
59 will automatically stop at that size as if -S had been given.
60 (Linux only): Watching file descriptor 3 opened by another process
62 1234:
63 pv -d 1234:3
65 (Linux only): Watching all file descriptors used by process 1234:
67 pv -d 1234
69
73 pv takes many options, which are divided into display switches, output
74 modifiers, and general options.
75
79 If no display switches are specified, pv behaves as if -p, -t, -e, -r,
80 and -b had been given (i.e. everything except average rate is switched
81 on). Otherwise, only those display types that are explicitly switched
82 on will be shown.
83 -p, --progress
85 Turn the progress bar on. If standard input is not a file and
86 no size was given (with the -s modifier), the progress bar can‐
87 not indicate how close to completion the transfer is, so it will
88 just move left and right to indicate that data is moving.
89 -t, --timer
91 Turn the timer on. This will display the total elapsed time
92 that pv has been running for.
93 -e, --eta
95 Turn the ETA timer on. This will attempt to guess, based on
96 previous transfer rates and the total data size, how long it
97 will be before completion. This option will have no effect if
98 the total data size cannot be determined.
99 -I, --fineta
101 Turn the ETA timer on, but display the estimated local time of
102 arrival instead of time left. When the estimated time is more
103 than 6 hours in the future, the date is shown as well.
104 -r, --rate
106 Turn the rate counter on. This will display the current rate of
107 data transfer.
108 -a, --average-rate
110 Turn the average rate counter on. This will display the average
111 rate of data transfer so far.
112 -b, --bytes
114 Turn the total byte counter on. This will display the total
115 amount of data transferred so far.
116 -T, --buffer-percent
118 Turn on the transfer buffer percentage display. This will show
119 the percentage of the transfer buffer in use - but see the
120 caveat under %T in the FORMATTING section below. Implies -C.
121 -A, --last-written NUM
123 Show the last NUM bytes written - but see the caveat under %nA
124 in the FORMATTING section below. Implies -C.
125 -F, --format FORMAT
127 Ignore the options -p, -t, -e, -r, -a, -b, -T, and -A, and in‐
128 stead use the format string FORMAT to determine the output for‐
129 mat. See the FORMATTING section below.
130 -n, --numeric
132 Numeric output. Instead of giving a visual indication of
133 progress, pv will give an integer percentage, one per line, on
134 standard error, suitable for piping (via convoluted redirection)
135 into dialog(1). Note that -f is not required if -n is being
136 used.
137 Note that if --numeric is in use, then adding --bytes will cause
139 the number of bytes processed so far to be output instead of a
140 percentage; if --line-mode is also in use, then instead of bytes
141 or a percentage, the number of lines so far is output. And fi‐
142 nally, if --timer is also in use, then each output line is pre‐
143 fixed with the elapsed time so far, as a decimal number of sec‐
144 onds.
145 -q, --quiet
147 No output. Useful if the -L option is being used on its own to
148 just limit the transfer rate of a pipe.
149
153 -W, --wait
154 Wait until the first byte has been transferred before showing
155 any progress information or calculating any ETAs. Useful if the
156 program you are piping to or from requires extra information be‐
157 fore it starts, eg piping data into gpg(1) or mcrypt(1) which
158 require a passphrase before data can be processed.
159 -D, --delay-start SEC
161 Wait until SEC seconds have passed before showing any progress
162 information, for example in a script where you only want to show
163 a progress bar if it starts taking a long time. Note that this
164 can be a decimal such as 0.5.
165 -s SIZE, --size SIZE
167 Assume the total amount of data to be transferred is SIZE bytes
168 when calculating percentages and ETAs. The same suffixes of
169 "k", "m" etc can be used as with -L.
170 Has no effect if used with -d PID to watch all file descriptors
172 of a process, but will work with -d PID:FD.
173 -l, --line-mode
175 Instead of counting bytes, count lines (newline characters). The
176 progress bar will only move when a new line is found, and the
177 value passed to the -s option will be interpreted as a line
178 count. Note that file sizes are not automatically calculated
179 when this option is used, to avoid having to read all files
180 twice.
181 -0, --null
183 Count lines as null terminated. This option implies
184 --line-mode.
185 -i SEC, --interval SEC
187 Wait SEC seconds between updates. The default is to update ev‐
188 ery second. Note that this can be a decimal such as 0.1.
189 -w WIDTH, --width WIDTH
191 Assume the terminal is WIDTH characters wide, instead of trying
192 to work it out (or assuming 80 if it cannot be guessed).
193 -H HEIGHT, --height HEIGHT
195 Assume the terminal is HEIGHT rows high, instead of trying to
196 work it out (or assuming 25 if it cannot be guessed).
197 -N NAME, --name NAME
199 Prefix the output information with NAME. Useful in conjunction
200 with -c if you have a complicated pipeline and you want to be
201 able to tell different parts of it apart.
202 -f, --force
204 Force output. Normally, pv will not output any visual display
205 if standard error is not a terminal. This option forces it to
206 do so.
207 -c, --cursor
209 Use cursor positioning escape sequences instead of just using
210 carriage returns. This is useful in conjunction with -N (name)
211 if you are using multiple pv invocations in a single, long,
212 pipeline.
213
217 -L RATE, --rate-limit RATE
218 Limit the transfer to a maximum of RATE bytes per second. A
219 suffix of "K", "M", "G", or "T" can be added to denote kibibytes
220 (*1024), mebibytes, and so on.
221 -B BYTES, --buffer-size BYTES
223 Use a transfer buffer size of BYTES bytes. A suffix of "K",
224 "M", "G", or "T" can be added to denote kibibytes (*1024),
225 mebibytes, and so on. The default buffer size is the block size
226 of the input file's filesystem multiplied by 32 (512KiB max), or
227 400KiB if the block size cannot be determined. This can be use‐
228 ful on platforms like MacOS which perform better in pipelines
229 with specific buffer sizes such as 1024. Implies -C.
230 -C, --no-splice
232 Never use splice(2), even if it would normally be possible. The
233 splice(2) system call is a more efficient way of transferring
234 data from or to a pipe than regular read(2) and write(2), but
235 means that the transfer buffer may not be used. This prevents
236 -A and -T from working, and makes -B redundant, so using -A, -T,
237 or -B automatically switches on -C. Switching on -C results in
238 a small loss of transfer efficiency. (This option has no effect
239 on systems where splice(2) is unavailable).
240 -E, --skip-errors
242 Ignore read errors by attempting to skip past the offending sec‐
243 tions. The corresponding parts of the output will be null
244 bytes. At first only a few bytes will be skipped, but if there
245 are many errors in a row then the skips will move up to chunks
246 of 512. This is intended to be similar to dd conv=sync,noerror
247 but has not been as thoroughly tested.
248 Specify -E twice to only report a read error once per file, in‐
250 stead of reporting each byte range skipped.
251 -S, --stop-at-size
253 If a size was specified with -s, stop transferring data once
254 that many bytes have been written, instead of continuing to the
255 end of input.
256 -d PID[:FD], --watchfd PID[:FD]
258 Instead of transferring data, watch file descriptor FD of
259 process PID, and show its progress. The pv process will exit
260 when FD either changes to a different file, changes read/write
261 mode, or is closed; other data transfer modifiers - and remote
262 control - may not be used with this option.
263 If only a PID is specified, then that process will be watched,
265 and all regular files and block devices it opens will be shown
266 with a progress bar. The pv process will exit when process PID
267 exits.
268 -R PID, --remote PID
270 If PID is an instance of pv that is already running, -R PID will
271 cause that instance to act as though it had been given this in‐
272 stance's command line instead. For example, if pv -L 123K is
273 running with process ID 9876, then running pv -R 9876 -L 321K
274 will cause it to start using a rate limit of 321KiB instead of
275 123KiB. Note that some options cannot be changed while running,
276 such as -c, -l, -f, -D, -E, and -S.
277
280 -P FILE, --pidfile FILE
281 Save the process ID of pv in FILE. The file will be truncated
282 if it already exists, and will be removed when pv exits. While
283 pv is running, it will contain a single number - the process ID
284 of pv - followed by a newline.
285 -h, --help
287 Print a usage message on standard output and exit successfully.
288 -V, --version
290 Print version information on standard output and exit success‐
291 fully.
292
296 If the -F option is given, then the output format is determined by the
297 given format string. Within that string, the following sequences can
298 be used:
299 %p Progress bar. Expands to fill the remaining space. Should only
301 be specified once. Equivalent to -p.
302 %t Elapsed time. Equivalent to -t.
304 %e ETA as time remaining. Equivalent to -e.
306 %I ETA as local time of completion. Equivalent to -I.
308 %r Current data transfer rate. Equivalent to -r.
310 %a Average data transfer rate. Equivalent to -a.
312 %b Bytes transferred so far (or lines if -l was specified). Equiv‐
314 alent to -b.
315 %T Percentage of the transfer buffer in use. Equivalent to -T.
317 Shows "{----}" if the transfer is being done with splice(2),
318 since splicing to or from pipes does not use the buffer.
319 %nA Show the last n bytes written (e.g. %16A for the last 16
321 bytes). Shows only dots if the transfer is being done with
322 splice(2), since splicing to or from pipes does not use the buf‐
323 fer.
324 %N Name prefix given by -N. Padded to 9 characters with spaces,
326 and suffixed with :.
327 %% A single %.
329 The format string equivalent of turning on all display switches is `%N
331 %b %T %t %r %a %p %e'.
332
336 Some suggested common switch combinations:
337 pv -ptebar
340 Show a progress bar, elapsed time, estimated completion time,
341 byte counter, average rate, and current rate.
342 pv -betlap
344 Show a progress bar, elapsed time, estimated completion time,
345 line counter, and average rate, counting lines instead of bytes.
346 pv -t Show only the elapsed time - useful as a simple timer, e.g.
348 sleep 10m | pv -t.
349 pv -pterb
351 The default behaviour: progress bar, elapsed time, estimated
352 completion time, current rate, and byte counter.
353 On MacOS, it may be useful to specify -B 1024 in a pipeline, as this
356 may improve performance.
357
361 An exit status of 1 indicates a problem with the -R or -P options.
362 Any other exit status is a bitmask of the following:
364 2 One or more files could not be accessed, stat(2)ed, or opened.
367 4 An input file was the same as the output file.
369 8 Internal error with closing a file or moving to the next file.
371 16 There was an error while transferring data from one or more in‐
373 put files.
374 32 A signal was caught that caused an early exit.
376 64 Memory allocation failed.
378 A zero exit status indicates no problems.
381
385 Written by Andrew Wood, with patches submitted by various other people.
386 Please see the package README for a complete list of contributors.
387
391 The following problems are known to exist in pv:
392 * The -c option does not work properly on Cygwin without cygserver
394 running, if started near the bottom of the screen (IPC is needed
395 to handle the terminal scrolling). To fix this, start cygserver
396 before using pv -c.
397 * The -R option is not available on Cygwin without cygserver run‐
399 ning (SYSV IPC is needed). To fix this, start cygserver before
400 running the instance of pv you want, at runtime, to change the
401 parameters of.
402 If you find any other problems, please report them.
404
408 Report bugs in pv to pv@ivarch.com or use the contact form linked from
409 the pv home page: <http://www.ivarch.com/programs/pv.shtml>
410
414 cat(1), dialog(1), splice(2)
415
419 This is free software, distributed under the ARTISTIC 2.0 license.
420Linux September 2021 PV(1)