.\" Copyright (c) 2013-2014 Devin Teske
.\" All rights reserved.
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.\" modification, are permitted provided that the following conditions
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" $FreeBSD$
.\"
.Dd Sep 7, 2014
.Dt DPV 1
.Os
.Sh NAME
.Nm dpv
.Nd stream data from stdin or multiple paths with dialog progress view
.Sh SYNOPSIS
.Nm
.Op options
.Ar [bytes:]label
.Nm
.Op options
.Fl m
.Ar [bytes1:]label1
.Ar path1
.Op Ar [bytes2:]label2 path2 ...
.Sh DESCRIPTION
.Nm
provides a dialog progress view, allowing a user to see current throughput rate
and total data transferred for one or more streams.
.Pp
The
.Nm
utility has two main modes for processing input.
.Pp
The default input mode, without
.Ql Fl m ,
.Nm
reads bytes from standard input.
A label for the data must be provided.
.Pp
The secondary input mode, with
.Ql Fl m ,
.Nm
reads multiple paths
.Pq up to 2047 or Dq ARG_MAX/2-1 ,
sequentially.
.Pp
Data read in either mode is either thrown away
.Pq default ,
sent to a spawned instance of the program specified via
.Ql Fl x Ar cmd ,
or sent to a unique file specified by
.Ql Fl o Ar file .
.Pp
With or without
.Ql Fl m ,
progress is displayed using one of
.Xr dialog 3
.Pq default ,
.Xr dialog 1
.Pq see Ql Fl D ,
or instead
.Xr Xdialog 1
.Pq see Ql Fl X .
.Pp
The following options are available:
.Bl -tag -width ".Fl b Ar backtitle"
.It Fl a Ar text
Display
.Ar text
below the file progress indicator(s).
.It Fl b Ar backtitle
Display
.Ar backtitle
on the backdrop, at top-left, behind the dialog widget.
When using
.Xr Xdialog 1 ,
this is displayed inside the window
.Pq at the top
followed by a separator line.
.It Fl d
Debug mode.
Print dialog prompt data to standard out and provide additional debugging on
standard error.
.It Fl D
Do not use the default interface of
.Xr dialog 3 ,
but instead spawn an instance of
.Xr dialog 1 .
The path to 
.Xr dialog 1
is taken from the
.Ev DIALOG
environment variable or simply
.Dq Li dialog
if unset or NULL.
.It Fl h
Produce a short syntax usage with brief option descriptions and exit.
Output is produced on standard error.
.It Fl i Ar format
Customize the single-file format string used to update the status line.
Ignored when using either
.Ql Fl D
or
.Ql Fl X
which lack the ability to display the status line
.Pq containing bytes/rate/thread information .
Default value
is
.Dq Li %'10lli bytes read @ %'9.1f bytes/sec. .
This format is used when handling one file.
.It Fl I Ar format
Customize the multi-file format string used to update the status line.
Ignored when using either
.Ql Fl D
or
.Ql Fl X
which lack the ability to display the status line
.Pq containing bytes/rate/thread information .
Default value
is
.Dq Li %'10lli bytes read @ %'9.1f bytes/sec. [%i/%i busy/wait] .
This format is used when handling more than one file.
.It Fl l
Line mode. Read lines from input instead of bytes.
.It Fl L Ar size
Label size.
If negative, shrink to longest label width.
.It Fl m
Multi-input mode.
Instead of reading bytes from standard input, read from a set of paths
.Pq one for each label .
By default, each path is processed sequentially in the order given.
.It Fl n Ar num
Display at-most
.Ar num
progress indicators per screen.
If zero, display as many as possible.
If negative, only display the main progress indicator.
Default is 0.
Maximum value is 10.
.It Fl N
No overrun.
If enabled, stop reading known-length inputs when input reaches stated length.
.It Fl o Ar file
Output data to
.Ar file .
The first occurrence of
.Ql %s
.Pq if any
in
.Ql Ar file
will be replaced with the
.Ar label
text.
.It Fl p Ar text
Display
.Ar text
above the file progress indicator(s).
.It Fl P Ar size
Mini-progressbar size.
If negative, don't display mini-progressbars
.Pq only the large overall progress indicator is shown .
If zero, auto-adjust based on number of files to read.
When zero and only one file to read, defaults to -1.
When zero and more than one file to read, defaults to 17.
.It Fl t Ar title
Display
.Ar title
atop the dialog box.
Note that if you use this option at the same time as
.Ql Fl X
and
.Ql Fl b Ar backtitle ,
the
.Ar backtitle
and
.Ar title
are effectively switched
.Pq see BUGS section below .
.It Fl T
Test mode.
Simulate reading a number of bytes, divided evenly across the number of files,
while stepping through each percent value of each file to process.
Appends
.Dq Li [TEST MODE]
to the status line
.Pq to override, use Ql Fl u Ar format .
No data is actually read.
.It Fl U Ar num
Update status line
.Ar num
times per-second.
Default value is
.Ql Li 2 .
A value of
.Ql Li 0
disables status line updates.
If negative, update the status line as fast as possible.
Ignored when using either
.Ql Fl D
or
.Ql Fl X
which lack the ability to display the status line
.Pq containing bytes/rate/thread information .
.It Fl w
Wide mode.
Allows long
.Ar text
arguments used with
.Ql Fl p
and
.Ql Fl a
to bump the dialog width.
Prompts wider than the maximum width will wrap
.Pq unless using Xr Xdialog 1 ; see BUGS section below .
.It Fl x Ar cmd
Execute
.Ar cmd
.Pq via Xr sh 1
and send it data that has been read.
Data is available to
.Ar cmd
on standard input.
With
.Ql Fl m ,
.Ar cmd
is executed once for each
.Ar path
argument.
The first occurrence of
.Ql %s
.Pq if any
in
.Ql Ar cmd
will be replaced with the
.Ar label
text.
.It Fl X
Enable X11 mode by using
.Xr Xdialog 1
instead of
.Xr dialog 1
or
.Xr dialog 3 .
.El
.Sh ENVIRONMENT
The following environment variables are referenced by
.Nm :
.Bl -tag -width ".Ev USE_COLOR"
.It Ev DIALOG
Override command string used to launch
.Xr dialog 1
.Pq requires Ql Fl D
or
.Xr Xdialog 1
.Pq requires Ql Fl X ;
default is either
.Ql dialog
.Pq for Ql Fl D
or
.Ql Xdialog
.Pq for Ql Fl X .
.It Ev DIALOGRC
If set and non-NULL, path to
.Ql .dialogrc
file.
.It Ev HOME
If
.Ql Ev $DIALOGRC
is either not set or NULL, used as a prefix to
.Ql .dialogrc
.Pq i.e., Ql $HOME/.dialogrc .
.It Ev USE_COLOR
If set and NULL, disables the use of color when using
.Xr dialog 1
.Pq does not apply to Xr Xdialog 1 .
.El
.Sh DEPENDENCIES
If using
.Ql Fl D ,
.Xr dialog 1
is required.
.Pp
If using
.Ql Fl X ,
.Xr Xdialog 1
is required.
.Sh FILES
.Bl -tag -width ".Pa $HOME/.dialogrc" -compact
.It Pa $HOME/.dialogrc
.El
.Sh EXAMPLES
.Pp
Simple example to show how fast
.Xr yes 1
produces lines
.Pq usually about ten-million per-second; your results may vary :
.Bd -literal -offset indent
yes | dpv -l yes
.Ed
.Pp
Display progress while timing how long it takes
.Xr yes 1
to produce a half-billion lines
.Pq usually under one minute; your results may vary :
.Bd -literal -offset indent
time yes | dpv -Nl 500000000:yes
.Ed
.Pp
An example to watch how quickly a file is transferred using
.Xr nc 1 :
.Bd -literal -offset indent
dpv -x "nc -w 1 somewhere.com 3000" -m label file
.Ed
.Pp
A similar example, transferring a file from another process and passing the
expected size to
.Nm :
.Bd -literal -offset indent
cat file | dpv -x "nc -w 1 somewhere.com 3000" 12345:label
.Ed
.Pp
A more complicated example:
.Bd -literal -offset indent
tar cf - . | dpv -x "gzip -9 > out.tgz" \\
	$( du -s . | awk '{print $1 * 1024}' ):label
.Ed
.Pp
Taking an image of a disk:
.Bd -literal -offset indent
dpv -o disk-image.img -m label /dev/ada0
.Ed
.Pp
Writing an image back to a disk:
.Bd -literal -offset indent
dpv -o /dev/ada0 -m label disk-image.img
.Ed
.Pp
Zeroing a disk:
.Bd -literal -offset indent
dpv -o /dev/md42 < /dev/zero
.Ed
.Pp
.Sh BUGS
.Xr Xdialog 1 ,
when given both
.Ql Fl -title Ar title
.Pq see above Ql Fl t Ar title
and
.Ql Fl -backtitle Ar backtitle
.Pq see above Ql Fl b Ar backtitle ,
displays the backtitle in place of the title and vice-versa.
.Pp
.Xr Xdialog 1
does not wrap long prompt texts received after initial launch.
This is a known issue with the
.Ql --gauge
widget in
.Xr Xdialog 1 .
.Pp
.Xr dialog 1
does not display the first character after a series of escaped escape-sequences
(e.g., ``\\\\n'' produces ``\\'' instead of ``\\n'').
This is a known issue with
.Xr dialog 1
and does not affect
.Xr dialog 3
or
.Xr Xdialog 1 .
.Pp
If your application ignores
.Ev USE_COLOR
when set and NULL before calling
.Xr dpv 1
with color escape sequences anyway,
.Xr dialog 3
and
.Xr dialog 1
may not render properly.
Workaround is to detect when
.Ev USE_COLOR
is set and NULL and either not use color escape sequences at that time or use
.Xr unset 1
.Xr [ sh 1 ]
or
.Xr unsetenv 1
.Xr [ csh 1 ]
to unset
.Ev USE_COLOR ,
forcing interpretation of color sequences.
This does not effect
.Xr Xdialog 1 ,
which renders the color escape sequences as plain text.
See
.Do Li
embedded "\\Z" sequences
.Dc
in
.Xr dialog 1
for additional information.
.Sh SEE ALSO
.Xr dialog 1 ,
.Xr dialog 3 ,
.Xr sh 1 ,
.Xr Xdialog 1
.Sh HISTORY
A
.Nm
utility first appeared in
.Fx 11.0 .
.Sh AUTHORS
.An Devin Teske Aq dteske@FreeBSD.org