Why not simply use join which takes care of most of what you want? Btw, $string1 and co are useless names for variables. The names should describe what is supposed to be in the variable. my $concatstring = join "\t", $string1, $string2, $string3; To take care of adding another tab for short strings, use map:

my $concatstring =
    join "\t",
    map length() < 8 ? "$_\t" : $_,
    $string1, $string2, $string3;
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But just to answer your question on how to return the result: quite coincidentally :), you can do that using return.

Makeshifts last the longest.