# charset="CP932"
# encoding="CP932"
# Tab を Space (長さ制限付き) に 伸張

#!/usr/bin/perl -wpi~
# JPerl 以外では Text::Tabs 使えよ
# use diagnostics;
use strict;

BEGIN {
	$tabstop ||= 8;
}

1	while s/^([^\t]+)(\t+)/ $1 . "\x20" x (length($2) * $tabstop - length($1) % $tabstop) /em;
__END__

#!/usr/local/bin/gawk -f 

BEGIN {
	tabstop = 8;
	spaces = "                                                                        ";
}

{
	while (match($0, /\t+/))
		sub(/\t+/, substr(spaces, 1, RLENGTH * tabstop - (RSTART - 1) % tabstop));

	print;
}