man pv Command

Man page for apt-get pv Command

Man Page for pv in Linux

Ubuntu Man Command : man pv

Man Pv  Command

This tutorial shows the man page for man pv in linux.

Open terminal with 'su' access and type the command as shown below:
man pv

Result of the Command Execution shown below:

PV(1)                            User Manuals                            PV(1)



NAME
pv monitor the progress of data through a pipe

SYNOPSIS
pv [OPTION] [FILE]...
pv [ h| V]



DESCRIPTION
pv allows a user to see 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.

To use it, insert it in a pipeline between two processes, with the
appropriate options. Its standard input will be passed through to its
standard output and progress will be shown on standard error.

pv will copy each supplied FILE in turn to standard output ( means
standard input), or if no FILEs are specified just standard input is
copied. This is the same behaviour as cat(1).

A simple example 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 s 12345 | nc w 1 somewhere.com 3000

A more complicated example using numeric output to feed into the dia
log(1) program for a full screen progress display:

(tar cf . \
| pv n s `du sb . | awk '{print $1}'` \
| gzip 9 > out.tgz) 2>&1 \
| dialog gauge 'Progress' 7 70

Frequent use of this third form is not recommended as it may cause the
programmer to overheat.



OPTIONS
pv takes many options, which are divided into display switches, output
modifiers, and general options.



DISPLAY SWITCHES
If no display switches are specified, pv behaves as if p, t, e, r,
and b had been given (i.e. everything is switched on). Otherwise, only
those display types that are explicitly switched on will be shown.

p, progress
Turn the progress bar on. If standard input is not a file and
no size was given (with the s modifier), the progress bar can
not indicate how close to completion the transfer is, so it will
just move left and right to indicate that data is moving.

t, timer
Turn the timer on. This will display the total elapsed time
that pv has been running for.

e, eta
Turn the ETA timer on. This will attempt to guess, based on
previous transfer rates and the total data size, how long it
will be before completion. 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.

b, bytes
Turn the total byte counter on. This will display the total
amount of data transferred so far.

n, numeric
Numeric output. Instead of giving a visual indication of
progress, pv will give an integer percentage, one per line, on
standard error, suitable for piping (via convoluted redirection)
into dialog(1). Note that f is not required if n is being
used.

q, quiet
No output. Useful if the L option is being used on its own to
just limit the transfer rate of a pipe.



OUTPUT MODIFIERS
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, eg piping data into gpg(1) or mcrypt(1) which
require a passphrase before data can be processed.

s SIZE, size SIZE
Assume the total amount of data to be transferred is SIZE bytes
when calculating percentages and ETAs. The same suffixes of
"k", "m" etc can be used as with L.

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 the s option will be interpreted as a line
count.

i SEC, interval SEC
Wait SEC seconds between updates. The default is to update
every second. Note that this can be a decimal such as 0.1.

w WIDTH, width WIDTH
Assume the terminal is WIDTH characters wide, instead of trying
to work it out (or assuming 80 if it cannot be guessed).

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).

N NAME, name NAME
Prefix the output information with NAME. Useful in conjunction
with c if you have a complicated pipeline and you want to be
able to tell different parts of it apart.

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 N (name)
if you are using multiple pv invocations in a single, long,
pipeline.



DATA TRANSFER MODIFIERS
L RATE, rate limit RATE
Limit the transfer to a maximum of RATE bytes per second. A
suffix of "k", "m", "g", or "t" can be added to denote kilobytes
(*1024), megabytes, and so on.

B BYTES, buffer size BYTES
Use a transfer buffer size of BYTES bytes. A suffix of "k",
"m", "g", or "t" can be added to denote kilobytes (*1024),
megabytes, and so on. The default buffer size is the block size
of the input file's filesystem multiplied by 32 (512kb max), or
400kb if the block size cannot be determined.

R PID, remote PID
If PID is an instance of pv that is already running, R PID will
cause that instance to act as though it had been given this
instance's command line instead. For example, if pv L 123k is
running with process ID 9876, then running pv R 9876 L 321k
will cause it to start using a rate limit of 321k instead of
123k. Note that some options cannot be changed while running,
such as c, l, and f.



GENERAL OPTIONS
h, help
Print a usage message on standard output and exit successfully.

V, version
Print version information on standard output and exit success
fully.



AUTHORS
Andrew Wood
http://www.ivarch.com/

Kevin Coyner
(Debian package maintainer)

Jakub Hrozek
(Fedora package maintainer)

Cedric Delfosse
(previous Debian package maintainer)

Eduardo Aguiar
(provided Portuguese [Brazilian] translation)

Stephane Lacasse
(provided French translation)
http://www.tecknojunky.com/

Marcos Kreinacke
(provided German translation)

Bartosz Fenski
(provided Polish translation, along with Krystian Zubel)
http://skawina.eu.org/

Joshua Jensen
(reported RPM installation bug)

Boris Folgmann
(reported cursor handling bug)
http://www.folgmann.com/en/

Mathias Gumz
(reported NLS bug)

Daniel Roethlisberger
(submitted patch to use lockfiles for c if terminal locking fails)

Adam Buchbinder
(lots of help with a Cygwin port of c)

Mark Tomich
(suggested B option)
http://metuchen.dyndns.org

Gert Menke
(reported bug when piping to dd with a large input buffer size)

Ville Herva
(informative bug report about rate limiting performance)

Elias Pipping
(patch to compile properly on Darwin 9)

Patrick Collison
(similar patch for OS X)

Boris Lohner
(reported problem that L does not complain if given non numeric value)

Laszlo Ersek
(reported shared memory leak on SIGINT with c)
http://phptest11.atw.hu/



BUGS
If you find any bugs, please contact the primary author, either by
email or by using the contact form on the web site.



SEE ALSO
cat(1), dialog(1)



LICENSE
This is free software, distributed under the ARTISTIC 2.0 license.



Linux March 2008 PV(1)


Related Topics

Apt Get Commands