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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | FORMATTING | EXAMPLES | EXIT STATUS | ENVIRONMENT | NOTES | REPORTING BUGS | SEE ALSO | COPYRIGHT | COLOPHON |
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PV(1) User Commands PV(1)
pv - monitor the progress of data through a pipe
pv [OPTION]... [FILE]...
pv -d|--watchfd PID[:FD] [OPTION]...
pv -R|--remote PID [OPTION]...
Show the progress of data through a pipeline by giving information
such as time elapsed, percentage completed (with progress bar),
current throughput rate, total data transferred, and ETA.
Each FILE is copied to standard output. With no FILE, or when
FILE is “-”, standard input is read. This is the same behaviour
as cat(1).
Display switches
If no display switches are specified, pv behaves as if
“--progress”, “--timer”, “--eta”, “--rate”, and “--bytes” had been
given. Otherwise, only those display types that are explicitly
switched on will be shown.
-p, --progress
Turn the progress bar on. If any inputs are not files, or
are unreadable, and no size was explicitly given with
“--size”, the progress bar cannot indicate how close to
completion the transfer is, so it will just move left and
right to indicate that data is moving - or, with “--gauge”,
the bar will indicate the current rate as a percentage of
the maximum rate seen so far.
-t, --timer
Turn the timer on. This will display the total elapsed
time that pv has been running for.
-e, --eta
Turn the ETA countdown on. This will estimate, based on
current transfer rates and the total data size, how long it
will be before completion. The countdown is prefixed with
“ETA”. This option will have no effect if the total data
size cannot be determined.
-I, --fineta
Turn the ETA countdown on, but display the estimated local
time at which the transfer will finish, instead of the
amount of time remaining. When the estimated time is more
than 6 hours in the future, the date is shown as well. The
time is prefixed with “FIN” for finish time. As with
“--eta”, this option will have no effect if the total data
size cannot be determined.
-r, --rate
Turn the rate counter on. This will display the current
rate of data transfer. The rate is shown in square
brackets “[]”.
-a, --average-rate
Turn the average rate counter on. This will display the
current average rate of data transfer, over the last 30
seconds by default (see “--average-rate-window”). The
average rate is shown in brackets “()”.
-b, --bytes
Turn the total byte counter on. This will display the
total amount of data transferred so far.
-T, --buffer-percent
Turn on the transfer buffer percentage display. This will
show the percentage of the transfer buffer in use. Implies
“--no-splice”. The transfer buffer percentage is shown in
curly brackets “{}”.
-A NUM, --last-written NUM
Show the last NUM bytes written. Implies “--no-splice”.
-F FORMAT, --format FORMAT
Ignore all of the above options and instead use the format
string FORMAT to determine the output format. See the
FORMATTING section below.
-n, --numeric
Numeric output. Instead of giving a visual indication of
progress, write an integer percentage, one per line, on
standard error, suitable for passing to a tool such as
dialog(1). Note that “--force” is not required if
“--numeric” is being used.
Combining “--numeric” with “--bytes” will cause the number
of bytes processed so far to be output instead of a
percentage. Adding “--line-mode” as well as “--bytes”
writes the number of lines instead of bytes or a
percentage. Adding “--rate” adds the transfer rate to each
output line (if “--bytes” is also in use, the rate comes
after the byte/line count). Adding “--timer” prefixes each
output line with the elapsed time so far, as a decimal
number of seconds.
Combining “--numeric” with “--format” allows for custom
output. The default format string components for
“--numeric” are “%t %b %r %{progress-amount-only}” in that
order, each item being active or inactive according to the
rules above (so the default with no other options is
“%{progress-amount-only}”.
-q, --quiet
No output. Useful if the “--rate-limit” option is being
used on its own to limit the transfer rate of a pipe.
Output modifiers
-8, --bits
Use bits instead of bytes for the byte and rate counters.
The output suffix will be “b” instead of “B”.
-k, --si
Display and interpret suffixes as multiples of 1000 rather
than the default of 1024. Note that this only takes effect
on options after this one, so for consistency, specify this
option first.
-W, --wait
Wait until the first byte has been transferred before
showing any progress information or calculating any ETAs.
Useful if the program you are piping to or from requires
extra information before it starts, such as when piping
data into gpg(1) or mcrypt(1) which require a passphrase
before data can be processed.
-D SEC, --delay-start SEC
Wait until SEC seconds have passed before showing any
progress information, for example in a script where you
only want to show a progress bar if it starts taking a long
time. The value of SEC can be a decimal such as “0.5”.
-s SIZE, --size SIZE
Assume the total amount of data to be transferred is SIZE
bytes when calculating percentages and ETAs. A suffix of
“K”, “M”, “G”, or “T” can be added to denote kibibytes
(*1024), mebibytes, gibibytes, tebibytes. If “--si”
appears before this option, suffixes will denote kilobytes
(*1000), megabytes, and so on instead.
If SIZE starts with “@”, the size of file whose name
follows the @ will be used.
-g, --gauge
If the progress bar is shown but the size is not known,
then instead of moving the bar left and right to show
progress, show the current transfer rate as a percentage of
the maximum rate seen so far.
-l, --line-mode
Instead of counting bytes, count lines (newline
characters). The progress bar will only move when a new
line is found, and the value passed to “--size” will be
interpreted as a line count.
If this option is used without “--size”, the "total size"
(in this case, total line count) is calculated by reading
through all input files once before transfer starts. If
any inputs are pipes or non-regular files, or are
unreadable, the total size will not be calculated.
-0, --null
Count lines as terminated with a null byte instead of with
a newline. This option implies “--line-mode”.
-i SEC, --interval SEC
Wait SEC seconds between updates. The default is to update
every second. The value of SEC can be a decimal such as
“0.1”.
-m SEC, --average-rate-window SEC
Compute current average rate over a SEC seconds window for
average rate and ETA calculations. The default is 30
seconds. The value must be an integer.
-w WIDTH, --width WIDTH
Assume the terminal is WIDTH columns wide, instead of
trying to work it out (or assuming 80 if it cannot be
guessed). If this option is used, the output width will
not be adjusted if the width of the terminal changes while
the transfer is running.
-H HEIGHT, --height HEIGHT
Assume the terminal is HEIGHT rows high, instead of trying
to work it out (or assuming 25 if it cannot be guessed).
If this option is used, the output height will not be
adjusted if the height of the terminal changes while the
transfer is running.
-N NAME, --name NAME
Prefix the output information with NAME. Useful in
conjunction with “--cursor” if you have a complicated
pipeline and you want to be able to tell different parts of
it apart.
-u STYLE, --bar-style STYLE
Change the default progress bar style shown by
“--progress”, or by the “--format” sequences “%{progress}”
or “%{progress-bar-only}”, to STYLE. The STYLE can be one
of plain (the default), block, granular, or shaded. These
styles are described in the FORMATTING section below.
-x SPEC, --extra-display SPEC
As well as displaying progress to the terminal, also write
it to SPEC. The SPEC must start with a comma-separated
list of destinations, and can optionally be followed by a
colon and a format string. The destinations can be
windowtitle or window for the xterm window title, and
processtitle, proctitle, process, or proc for the process
title displayed by ps(1). If a format string is not
supplied, the same format is used as for the terminal. For
example, “-x 'window,process:%t %b %r'” will show the
elapsed time, bytes transferred, and rate, in both the
window title and the process title.
-v, --stats
At the end of the transfer, write an additional line
showing the transfer rate minimum, maximum, mean, and
standard deviation. The values are always in bytes per
second (or bits, with “--bits”).
-f, --force
Force output. Normally, pv will not output any visual
display if standard error is not a terminal. This option
forces it to do so.
-c, --cursor
Use cursor positioning escape sequences instead of just
using carriage returns. This is useful in conjunction with
“--name” if you are using multiple pv invocations in a
single pipeline.
Data transfer modifiers
-o FILE, --output FILE
Write data to FILE instead of standard output. If the file
already exists, it will be truncated.
-L RATE, --rate-limit RATE
Limit the transfer to a maximum of RATE bytes per second.
The same suffixes as “--size” can be used.
-B BYTES, --buffer-size BYTES
Use a transfer buffer size of BYTES bytes. The same
suffixes as “--size” can be used. The default buffer size
is the block size of the input file's filesystem multiplied
by 32 (512KiB max), or 400KiB if the block size cannot be
determined. This can be useful on platforms like macOS
with pipelines that perform better with specific buffer
sizes such as 1024. Implies “--no-splice”.
-C, --no-splice
Never use splice(2), even if it would normally be possible.
The splice(2) system call is a more efficient way of
transferring data from or to a pipe than regular read(2)
and write(2), but means that the transfer buffer may not be
used. This prevents “--buffer-percent” and
“--last-written” from working, cannot work with
“--discard”, and makes “--buffer-size” redundant, so using
any of those options automatically switches on
“--no-splice”. Switching on this option results in a small
loss of transfer efficiency. It has no effect on systems
where splice(2) is unavailable.
-E, --skip-errors
Ignore read errors by attempting to skip past the offending
sections. The corresponding parts of the output will be
null bytes. At first only a few bytes will be skipped, but
if there are many errors in a row then the skips will move
up to chunks of 512. This is intended to be similar to
“dd conv=sync,noerror”.
Specify “--skip-errors” twice to only report a read error
once per file, instead of reporting each byte range
skipped.
-Z BYTES, --error-skip-block BYTES
When ignoring read errors with “--skip-errors”, instead of
trying to adaptively skip by reading small amounts and
skipping progressively larger sections until a read
succeeds, move to the next file block of BYTES bytes as
soon as an error occurs. There may still be some shorter
skips where the block being skipped coincides with the end
of the transfer buffer. The same suffixes as “--size” can
be used.
This option can only be used with “--skip-errors” and is
intended for use when reading from a block device, such as
“--skip-errors --error-skip-block 4K” to skip in 4 kibibyte
blocks. This will speed up reads from faulty media, at the
expense of potentially losing more data.
-S, --stop-at-size
If a size was specified with “--size”, stop transferring
data once that many bytes have been written, instead of
continuing to the end of input.
-Y, --sync
After every write operation, synchronise the buffer caches
to disk with fdatasync(2). This has no effect when the
output is a pipe. Using “--sync” may improve the accuracy
of the progress bar when writing to a slow disk.
-K, --direct-io
Set the O_DIRECT flag on all inputs and outputs, if it is
available. This will minimise the effect of caches, at the
cost of performance. Due to memory alignment requirements,
it also may cause read or write failures with an error of
“Invalid argument”, especially if reading and writing files
across a variety of filesystems in a single pv call. Use
this option with caution.
-X, --discard
Instead of transferring input data to standard output,
discard it. This is equivalent to redirecting standard
output to /dev/null, except that write(2) is never called.
Implies “--no-splice”.
-U FILE, --store-and-forward FILE
Instead of passing data through immediately, do it in two
stages - first read all input and write it to FILE, and
then once the input is exhausted, read all of FILE and
write it to the output. FILE remains in place afterwards,
unless it is “-”, in which case pv creates a temporary file
for this purpose, and automatically removes it afterwards.
This can be useful if you have a pipeline which generates
data (your input) quickly but you don't know the size, and
you wish to pass it to some slower process, once all of the
input has been generated and you know its size, so you can
see its progress. Note that when doing this with
relatively small amounts of data, “--no-splice” may be
preferable so that pipe buffering doesn't affect the
progress display.
Alternative operating modes
-d PID[:FD], --watchfd PID[:FD]
Instead of transferring data, watch file descriptor FD of
process PID, and show its progress. The pv process will
exit when FD either changes to a different file, changes
read/write mode, or is closed; other data transfer
modifiers - and remote control - may not be used with this
option.
If only a PID is specified, then that process will be
watched, and all regular files and block devices it opens
will be shown with a progress bar. The pv process will
exit when process PID exits.
-R PID, --remote PID
Remotely control another instance of pv with process ID
PID, making it act as though it had been given this
instance's command line. For example, if
“pv --rate-limit 123K” is running with process ID 9876,
then running “pv --remote 9876 --rate-limit 321K” will
cause process 9876 to start using a rate limit of 321KiB
instead of 123KiB. Note that some options cannot be
changed while running, such as “--cursor”, “--line-mode”,
“--force”, “--delay-start”, “--skip-errors”, and
“--stop-at-size”.
Other options
-P FILE, --pidfile FILE
Save the process ID of pv in FILE. The file will be
replaced if it already exists, and will be removed when pv
exits. While pv is running, FILE will contain a single
number - the process ID of pv - followed by a newline.
-h, --help
Print a usage message on standard output and exit
successfully.
-V, --version
Print version information on standard output and exit
successfully.
Format strings used by “--format” and “--extra-display” can
contain the following sequences:
%p, %{progress}
Progress bar (suffixed with a percentage if the size is
known). Equivalent to “--progress”. Expands to fill the
remaining space unless prefixed by a number to set the
width, such as “%20p” or “%20{progress}”.
%{progress-bar-only}
Progress bar, without any sides, and without any percentage
displayed afterwards. Expands to fill the remaining space
unless prefixed by a number.
%{progress-amount-only}
The percentage completion (or maximum rate, with “--gauge”
when the size is unknown).
%{bar-plain}
Progress bar in the standard plain format, without any
sides, and without any percentage displayed afterwards.
Expands to fill the remaining space unless prefixed by a
number.
%{bar-block}
Progress bar using Unicode full blocks, without any sides,
and without any percentage displayed afterwards. Expands
to fill the remaining space unless prefixed by a number.
If UTF-8 output is not available, the plain format is used.
%{bar-granular}
Progress bar using Unicode full blocks, and 1/8th blocks
for partial fills, providing a more granular display. Like
the other “%{bar}” strings this shows the bar without any
sides, and without any percentage displayed afterwards, and
expands to fill the remaining space unless prefixed by a
number. If UTF-8 output is not available, the plain format
is used.
%{bar-shaded}
Progress bar using Unicode full blocks and shade characters
- dark and medium shade are used for partial fills, and the
light shade is used for the background. Like the other
“%{bar}” strings this shows the bar without any sides, and
without any percentage displayed afterwards, and expands to
fill the remaining space unless prefixed by a number. If
UTF-8 output is not available, the plain format is used.
%t, %{timer}
Elapsed time. Equivalent to “--timer”.
%e, %{eta}
ETA as time remaining. Equivalent to “--eta”.
%I, %{fineta}
ETA as local time at which the transfer will finish.
Equivalent to “--fineta”.
%r, %{rate}
Current data transfer rate. Equivalent to “--rate”.
%a, %{average-rate}
Average data transfer rate. Equivalent to
“--average-rate”.
%b, %{bytes}, %{transferred}
Bytes transferred so far (or lines if “--line-mode” was
specified). Equivalent to “--bytes”. If “--bits” was
specified, “%b” shows the bits transferred so far, not
bytes.
%T, %{buffer-percent}
Percentage of the transfer buffer in use. Equivalent to
“--buffer-percent”. Displays “{----}” if the transfer is
being done with splice(2), since splicing to or from pipes
does not use the buffer.
%nA, %n{last-written}
Show the last n bytes written (for example, “%16A” shows
the last 16 bytes). Shows only dots if the transfer is
being done with splice(2), since splicing to or from pipes
does not use the buffer.
%nL, %n{previous-line}
Show the first n bytes of the most recently written line
(for example, “%40L” shows the first 40 bytes). If no n is
given, then this expands to fill the available space.
Shows only spaces if the transfer is being done with
splice(2).
%N, %{name}
Show the name prefix given by “--name”. Padded to 9
characters with spaces, and suffixed with “:”.
%{sgr:colour,...}
Emit ECMA-48 SGR (Select Graphic Rendition) codes if the
terminal supports colours, where colour,... is a comma-
separated list of any of the keywords below, or the numeric
values from console_codes(4). If colour support is not
available, nothing is emitted.
Supported keywords are: reset or none, black, red, green,
brown or yellow, blue, magenta, cyan, white, fg-black,
fg-red, fg-green, fg-brown or fg-yellow, fg-blue,
fg-magenta, fg-cyan, fg-white, fg-default, bg-black,
bg-red, bg-green, bg-brown or bg-yellow, bg-blue,
bg-magenta, bg-cyan, bg-white, bg-default, bold, dim,
italic, underscore or underline, blink, reverse, no-bold or
no-dim, no-italic, no-underscore or no-underline, no-blink,
no-reverse.
With colours, the optional "fg-" prefix indicates
foreground; a prefix of "bg-" indicates background.
For example, “%{sgr:green,bold}TEXT%{sgr:reset}“ will make
TEXT bold green on supported terminals.
%% A single “%”.
Any other contents are reproduced in the progress display as-is.
The format string equivalent of the default display switches is
“%b %t %r %p %e”.
Some suggested common switch combinations:
pv -ptebar
Show a progress bar, elapsed time, estimated completion
time, byte counter, average rate, and current rate.
pv -betlap
Show a progress bar, elapsed time, estimated completion
time, line counter, and average rate, counting lines
instead of bytes.
pv -btrpg
Show the amount transferred, elapsed time, current rate,
and a gauge showing the current rate as a percentage of the
maximum rate seen - useful in a pipeline where the total
size is unknown. (If the size is known, these options will
show the percentage completion instead of the rate gauge).
pv -t Show only the elapsed time - useful as a simple timer, such
as “sleep 10m | pv -t”.
pv -pterb
The default behaviour: progress bar, elapsed time,
estimated completion time, current rate, and byte counter.
On macOS, it may be useful to specify “--buffer-size 1024” in a
pipeline, as this may improve performance.
To watch how quickly a file is transferred using nc(1):
pv file | nc -w 1 somewhere.com 3000
A similar example, transferring a file from another process and
passing the expected size to pv:
cat file | pv --size 12345 | nc -w 1 somewhere.com 3000
To watch the progress of creating a tar.gz archive:
tar cf - directory/ \
| pv --size $(du -sb directory/ | awk '{print $1}') \
| gzip -9 \
> out.tar.gz
Taking an image of a disk, skipping errors:
pv -EE /dev/your/disk/device > disk-image.img
Writing an image back to a disk:
pv disk-image.img > /dev/your/disk/device
Zeroing a disk:
pv < /dev/zero > /dev/your/disk/device
Note that if the input size cannot be calculated, and the output
is a block device, then the size of the block device will be used
and pv will automatically stop at that size as if “--stop-at-size”
had been given.
(Linux and macOS only): Watching file descriptor 3 opened by
another process 1234:
pv --watchfd 1234:3
(Linux and macOS only): Watching all file descriptors used by
process 1234:
pv --watchfd 1234
Rate-limiting the transfer between two processes in a pipeline,
with no display:
producer | pv --quiet --rate-limit 1M | consumer
Sending logs to a processing script, showing the most recent line
as part of the progress display:
pv --format '%a %p : %L' big.log | processing-script
Showing progress as lines of JSON data:
pv --numeric --format '{"elapsed":%t,"bytes":%b,"rate":%r,"percentage":%{progress-amount-only}}' big.log | processing-script
An exit status of 1 indicates a problem with the “--remote” or
“--pidfile” options.
Any other exit status is a bitmask of the following:
2 One or more files could not be accessed, stat(2)ed, or
opened.
4 An input file was the same as the output file.
8 Internal error with closing a file or moving to the next
file.
16 There was an error while transferring data from one or more
input files.
32 A signal was caught that caused an early exit.
64 Memory allocation failed.
A zero exit status indicates no problems.
The following environment variables may affect pv:
HOME The current user's home directory. This may be used by
“--remote” to exchange messages between pv instances: if
the /run/user/UID/ directory does not exist (where UID is
the current user ID), then $HOME/.pv/ will be used instead.
TMPDIR, TMP
The directory to create per-tty lock files for the terminal
when using “--cursor”. If TMPDIR is set to a non-empty
value, it is the directory under which lock files are
created. Otherwise, TMP is used. If neither are set, then
/tmp is used.
In some versions of bash(1) and zsh(1), the construct
“<(pv filename)” will not output any progress to the terminal when
run from an interactive shell, due to the subprocess being run in
a separate process group from the one that owns the terminal. In
these cases, use “--force”.
If pv is used in a pipeline in zsh version 5.8, and the last
command in the pipeline is based on shell builtins, zsh takes
control of the terminal away from pv, preventing progress from
being displayed. For example, this will produce no progress bar:
pv InputFile | { while read -r line; do sleep 0.1; done; }
To work around this, put the last commands of the pipeline in
normal brackets to force the use of a subshell:
pv InputFile | ( while read -r line; do sleep 0.1; done; )
Refer to issue #105 ⟨https://codeberg.org/a-j-wood/pv/issues/105⟩
for full details.
The “--remote” option requires that either /run/user/<uid>/ or
$HOME/ can be written to, for inter-process communication.
The “--size” option has no effect if used with “--watchfd PID” to
watch all file descriptors of a process, but will work with
“--watchfd PID:FD” to watch a single file descriptor.
If the input size cannot be calculated, and the output is a block
device, then pv will read the output device's size, use that as if
it had been passed to “--size”, and activate “--stop-at-size”.
The “%nA” and “%nL” format sequences may not be effective with
small input files, and “%nL” may be a few lines out due to
buffering within the pipeline itself.
Numbers passed to “--size”, “--rate-limit”, “--buffer-size”, and
“--error-skip-block” may all be expressed as decimals if followed
by a suffix, so for example “--size 1.5G” is equivalent to
“--size 1536M”.
Numbers passed to “--interval” and “--delay-start” may be integers
or decimals, but may not have a suffix.
Numbers passed to “--last-written”, “--width”, “--height”,
“--average-rate-window”, and “--remote” must be integers with no
suffix.
Please report any bugs to [email protected].
Alternatively, use the issue tracker linked from the pv home page
⟨https://www.ivarch.com/programs/pv.shtml⟩.
cat(1), splice(2), fdatasync(2), open(2) (for O_DIRECT),
console_codes(4)
Copyright © 2002-2008, 2010, 2012-2015, 2017, 2021, 2023-2025
Andrew Wood.
License GPLv3+: GNU GPL version 3 or later
⟨https://www.gnu.org/licenses/gpl-3.0.html⟩.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Please see the package's ACKNOWLEDGEMENTS file for a complete list
of contributors.
This page is part of the pv (Pipe Viewer) project. Information
about the project can be found at
⟨http://www.ivarch.com/programs/pv.shtml⟩. If you have a bug
report for this manual page, see
⟨http://www.ivarch.com/programs/pv.shtml⟩. This page was obtained
from the tarball pv-1.9.31.tar.gz fetched from
⟨http://www.ivarch.com/programs/pv.shtml⟩ on 2025-02-02. If you
discover any rendering problems in this HTML version of the page,
or you believe there is a better or more up-to-date source for the
page, or you have corrections or improvements to the information
in this COLOPHON (which is not part of the original manual page),
send a mail to [email protected]
pv-1.9.31 2025-01-28 PV(1)
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