my $g_tab_width = 4;
my $s1 = "xxxx\tyyyy\tzzzz";
$s1 =~ s{(.*?)\t}{$1.(' ' x
($g_tab_width - length($1) % $g_tab_width))}ge;
my $s2 = "xxxx\tyyyy\tzzzz";
$s2 =~ s/(.*?)\t/$1 /g;
print $s1, "\n", $s2, "\n";
bXkgJGdfdGFiX3dpZHRoID0gNDsKCm15ICRzMSA9ICJ4eHh4XHR5eXl5XHR6enp6IjsKJHMxID1+IHN7KC4qPylcdH17JDEuKCcgJyB4ICgkZ190YWJfd2lkdGggLSBsZW5ndGgoJDEpICUgJGdfdGFiX3dpZHRoKSl9Z2U7CgpteSAkczIgPSAieHh4eFx0eXl5eVx0enp6eiI7CiRzMiA9fiAgcy8oLio/KVx0LyQxICAgIC9nOwoKcHJpbnQgJHMxLCAiXG4iLCAkczIsICJcbiI7Cg==