use Text::Tabs;

$tabstop = 8;                            # set tab spacing to 8 (default)
print expand("Hello\tworld");            # convert tabs to spaces in output
print unexpand("Hello,        world");   # convert spaces to tabs in output
$tabstop = 4;                            # set tab spacing to 4
print join("\n", expand(split(/\n/,
                "Hello\tworld, \nit's a nice day.\n")));