PostgreSQL uses a pager to display the results of an operation you performed when you are using the command line tool (psql).
You can disable the pager by issuing:
pset pager off
with which you specifically request that the pager is disabled. You can re-enable the pager by issuing:
pset pager on
with which you specifically request that the pager is enabled. Alternatively you can toggle the status of the pager by issuing
which depending on the current status of the pager will either enable or disable it.