Like `sed` or `tr`:

<!-- exec -->

    $ perl -pe 'tr/[a-z]/[A-Z]/' examples/authors.tsv | column -t
    ROBINSON  EDEN
    WARING    GWENDOLYN  L.
    BRUNNER   JOHN
    TOLKIEN   JOHN       RONALD  REUEL
    WALTON    JO
    TOEWS     MIRIAM
    CADIGAN   PAT
    LE        GUIN       URSULA  K.
    VESELKA   VANESSA
    WELLS     MARTHA
    LECKIE    ANN

<!-- end -->