#/usr/bin/perl

# Usage: retab [-<tabwidth>] [files]

$sw = 4;
$sw = $1, shift if $ARGV[0] =~ /^-(\d+)/;

while (<>) {
    s#^(\t+)#' ' x (length($1) * 8)#e;
    s#^( *)#' ' x (length($1) * $sw / 8)#e;
    s#^(( {8})*)#"\t" x (length($1) / 8)#e;
    print;
}