pg_upgrade cmdline issue

Good day,

why's that?

(user is postgres, who owns /var/lib/pgsql/data/)

bash-2.05$ bin/pg_upgrade -D /var/lib/pgsql/data/ -1
You must run pg_upgrade in either mode 1 or mode 2.
Usage: pg_upgrade [-D datadir] -1 | -2
bash-2.05$

Markus Bertheau