#!/usr/bin/perl

#---------------------------------------------------------------------
+-------
# Copyright (C) 2001-2003 Ed Halley
#---------------------------------------------------------------------
+-------

=head1 NAME

peek - eat lines of standard input; output a one-line preview instead

=head1 SYNOPSIS

    tar jcvf home.tar.bz2 /home | peek

=head1 DESCRIPTION

The peek process reads line-oriented text from the standard input, and
outputs each line atop each other on the standard output.  This is use
+ful
for reducing visual clutter in large list-oriented processing while
keeping some visual feedback of the progress.

There are a few options to customize the style, but the defaults are
usually quite sufficient.

=cut

#---------------------------------------------------------------------
+--------

use Getopt::Long;

use warnings;
use strict;

my $wide = 79;
my $keep = 0;

my %options =
    ( 'wide|width=i' => \$wide,
      'keep!' => \$keep,
      );

GetOptions(%options) or die;

$wide = 0 if $wide < 1;

#---------------------------------------------------------------------
+--------

$| = 1;
while (<>)
{
    chomp;
    tr{\n\t}{\r };
    printf "%-${wide}.${wide}s\r", $_;
}
print ' 'x$wide, "\r" if not $keep;
print "\n" if $keep;
exit(0);

__END__

#---------------------------------------------------------------------
+--------

=head1 OPTIONS

=over 4

=item B<--width>=[integer]

Truncates the output lines to the given width, so as to avoid any line
wrapping issues.  Default is 79 characters wide.

=item B<--keep>

The final line of output is left visible on the display.

=head1 BUGS

The --width should default to the current terminal width, if it can be
determined.

This animation assumes that a carriage return (as opposed to a newline
+ or
linefeed) will not erase the current line, but will return the output
cursor to the beginning of the current line.  This is a common convent
+ion
and holds true for many POSIX-styled terminals, but may not work for a
+ll
output devices.

=head1 LICENSE

Copyright (C) 2001-2003  Ed Halley  <ed@halley.cc>

This program is free software; you can redistribute it and/or modify i
+t
under the same terms as Perl itself.  For details on the Perl Artistic
License, read the F<http://www.perl.com/language/misc/Artistic.html>
page.

=cut

[download]

In reply to peek - output a one-line preview of stdin by halley

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.