linux - "cannot write to log file pg_upgrade_internal.log" when upgrading from Postgresql 9.1 to 9.3 -

i keep on getting above error whenever run following command via postgres user.

/usr/lib/postgresql/9.3/bin/pg_upgrade \    -b /usr/lib/postgresql/9.1/bin/ \    -b /usr/lib/postgresql/9.3/bin/ \    -d /var/lib/postgresql/9.1/main \    -d /var/lib/postgresql/9.3/main 

cannot write log file pg_upgrade_internal.log failure, exiting

i'm using ubuntu 13.10. both postgresql 9.1 , 9.3 running properly.

make sure run command directory writable postgres user, /tmp or /var/lib/postgresql:

$ cd /tmp $ usr/lib/postgresql/9.3/bin/pg_upgrade ...